- bookworm 4.4.0+dfsg-1
| SCONS(1) | SCons __VERSION__ | SCONS(1) |
NAME¶
scons - a software construction tool
SYNOPSIS¶
scons [options...] [name=val...] [targets...]
DESCRIPTION¶
scons orchestrates the construction of software (and other tangible products such as documentation files) by determining which component pieces must be built or rebuilt and invoking the necessary commands to build them. SCons offers many features to improve developer productivity such as parallel builds, caching of build artifacts, automatic dependency scanning, and a database of information about previous builds so details do not have to be recalculated each run.
scons requires Python 3.6 or later to run; there should be no other dependencies or requirements, unless the experimental Ninja tool is used.
Changed in version 4.3.0: support for Python 3.5 is removed; the CPython project has retired 3.5: https://www.python.org/dev/peps/pep-0478.
You set up an SCons build system by writing a script that describes things to build (targets), and, if necessary, the rules to build those files (actions). SCons comes with a collection of Builder methods which apply premade actions for building many common software components such as executable programs, object files and libraries, so that for many software projects, only the targets and input files (sources) need be specified in a call to a builder. SCons thus can operate at a level of abstraction above that of pure filenames. For example if you specify a library target named "foo", SCons keeps track of the actual operating system dependent filename (such as libfoo.so on a GNU/Linux system), and how to refer to that library in later construction steps that want to use it, so you don't have to specify that precise information yourself. SCons can also scan automatically for dependency information, such as header files included by source code files (for example, #include preprocessor directives in C or C++ files), so these implicit dependencies do not have to be specified manually. SCons supports the ability to define new scanners to support additional input file types.
Information about files involved in the build, including a cryptographic hash of the contents of source files, is cached for later reuse. By default this hash (the content signature) is used to determine if a file has changed since the last build, although this can be controlled by selecting an appropriate Decider function. Implicit dependency files are also part of out-of-date computation. The scanned implicit dependency information can optionally be cached and used to speed up future builds. A hash of each executed build action (the build signature) is cached, so that changes to build instructions (changing flags, etc.) or to the build tools themselves (new version) can also trigger a rebuild.
SCons supports the concept of separated source and build directories through the definition of variant directories (see the VariantDir function).
When invoked, scons looks for a file named SConstruct in the current directory and reads the build configuration from that file (other names are allowed, see the section called “SConscript Files” and the -f option for more information). The build may be structured in a hierarchical manner: the SConstruct file may specify subsidiary configuration files by calling the SConscript function, and these may, in turn, do the same. By convention, these subsidiary files are named SConscript, although any name may be used. As a result of this naming convention, the term SConscript files is used to refer generically to the complete set of configuration files for a project (including the SConstruct file), regardless of the actual file names or number of such files. A hierarchical build is not recursive - all of the SConscript files are processed in a single pass, although each is processed in a separate context so as not to interfere with one another. SCons provides mechanisms for information to be shared between SConscript files when needed.
Before reading the SConscript files, scons looks for a directory named site_scons in various system directories and in the directory containing the SConstruct file or, if specified, the directory from the --site-dir option instead, and prepends the ones it finds to the Python module search path (sys.path), thus allowing modules in such directories to be imported in the normal Python way in SConscript files. For each found site directory, (1) if it contains a file site_init.py that file is evaluated, and (2) if it contains a directory site_tools the path to that directory is prepended to the default toolpath. See the --site-dir and --no-site-dir options for details on default paths and controlling the site directories.
SConscript files are written in the Python programming language, although it is normally not necessary to be a Python programmer to use scons effectively. SConscript files are invoked in a context that makes the facilities described in this manual page available in their local namespace without any special steps. Standard Python scripting capabilities such as flow control, data manipulation, and imported Python libraries are available to use to handle complicated build situations. Other Python files can be made a part of the build system, but they do not automatically have the SCons context and need to import it if they need access (described later).
scons reads and executes all of the included SConscript files before it begins building any targets. To make this clear, scons prints the following messages about what it is doing:
$ scons foo.out scons: Reading SConscript files ... scons: done reading SConscript files. scons: Building targets ... cp foo.in foo.out scons: done building targets. $
The status messages (lines beginning with the scons: tag) may be suppressed using the -Q option.
To assure reproducible builds, SCons uses a restricted execution environment for running external commands used to build targets, rather then propagating the full environment in effect at the time scons was called. This helps avoid problems like picking up accidental settings, temporary debug values that are no longer needed, or one developer having different settings than another (or than the CI/CD pipeline). Environment variables that are needed for proper operation of such commands need to be set explicitly, which can be done either by assigning the desired values, or by picking values individually out of environment variables using the Python os.environ dictionary. The execution environment for a given construction environment is contained in its $ENV construction variable. A few environment variables are picked up automatically - see the section called “ENVIRONMENT”).
In particular, if the compiler or other commands that you want to use to build your target files are not in standard system locations, scons will not find them unless you explicitly include the locations into the PATH element of the execution environment. One example approach is to extract the entire PATH environment variable and set that into the execution environment:
import os
env = Environment(ENV={'PATH': os.environ['PATH']})
Similarly, if the commands use specific external environment variables that scons does not recognize, they can be propagated into the execution environment:
import os env = Environment(
ENV={
'PATH': os.environ['PATH'],
'ANDROID_HOME': os.environ['ANDROID_HOME'],
'ANDROID_NDK_HOME': os.environ['ANDROID_NDK_HOME'],
} )
Or you may explicitly propagate the invoking user's complete external environment:
import os env = Environment(ENV=os.environ.copy())
This comes at the expense of making your build dependent on the user's environment being set correctly, but it may be more convenient for many configurations. It should not cause problems if done in a build setup which tightly controls how the environment is set up before invoking scons, as in many continuous integration setups.
scons is normally executed in a top-level directory containing an SConstruct file. When scons is invoked, the command line (including the contents of the SCONSFLAGS environment variable, if set) is processed. Command-line options (see the section called “OPTIONS”) are consumed. Any variable argument assignments are collected, and remaining arguments are taken as targets to build.
Values of variables to be passed to the SConscript files may be specified on the command line:
scons debug=1
These variables are available through the ARGUMENTS dictionary, and can be used in the SConscript files to modify the build in any way:
if ARGUMENTS.get('debug', 0):
env = Environment(CCFLAGS='-g')
else:
env = Environment()
The command-line variable arguments are also available in the ARGLIST list, indexed by their order on the command line. This allows you to process them in order rather than by name, if necessary. Each ARGLIST entry is a tuple containing (argname, argvalue).
See the section called “Command-Line Construction Variables” for more information.
scons can maintain a cache of target (derived) files that can be shared between multiple builds. When derived-file caching is enabled in an SConscript file, any target files built by scons will be copied to the cache. If an up-to-date target file is found in the cache, it will be retrieved from the cache instead of being rebuilt locally. Caching behavior may be disabled and controlled in other ways by the --cache-force, --cache-disable, --cache-readonly, and --cache-show command-line options. The --random option is useful to prevent multiple builds from trying to update the cache simultaneously.
By default, scons searches for known programming tools on various systems and initializes itself based on what is found. On Windows systems which identify as win32, scons searches in order for the Microsoft Visual C++ tools, the MinGW tool chain, the Intel compiler tools, and the PharLap ETS compiler. On Windows system which identify as cygwin (that is, if scons is invoked from a cygwin shell), the order changes to prefer the GCC toolchain over the MSVC tools. On OS/2 systems, scons searches in order for the OS/2 compiler, the GCC tool chain, and the Microsoft Visual C++ tools, On SGI IRIX, IBM AIX, Hewlett Packard HP-UX, and Oracle Solaris systems, scons searches for the native compiler tools (MIPSpro, Visual Age, aCC, and Forte tools respectively) and the GCC tool chain. On all other platforms, including POSIX (Linux and UNIX) platforms, scons searches in order for the GCC tool chain, and the Intel compiler tools. These default values may be overridden by appropriate setting of construction variables.
Target Selection¶
SCons acts on the selected targets, whether the requested operation is build, no-exec or clean. Targets are selected as follows:
To ignore the default targets specified through calls to Default and instead build all target files in or below the current directory specify the current directory (.) as a command-line target:
scons .
To build all target files, including any files outside of the current directory, supply a command-line target of the root directory (on POSIX systems):
scons /
or the path name(s) of the volume(s) in which all the targets should be built (on Windows systems):
scons C:\ D:\
A subset of a hierarchical tree may be built by remaining at the top-level directory (where the SConstruct file lives) and specifying the subdirectory as the target to build:
scons src/subdir
or by changing directory and invoking scons with the -u option, which traverses up the directory hierarchy until it finds the SConstruct file, and then builds targets relatively to the current subdirectory (see also the related -D and -U options):
cd src/subdir scons -u .
In all cases, more files may be built than are requested, as scons needs to make sure any dependent files are built.
Specifying "cleanup" targets in SConscript files is usually not necessary. The -c flag removes all selected targets:
scons -c .
to remove all target files in or under the current directory, or:
scons -c build export
to remove target files under build and export.
Additional files or directories to remove can be specified using the Clean function in the SConscript files. Conversely, targets that would normally be removed by the -c invocation can be retained by calling the NoClean function with those targets.
scons supports building multiple targets in parallel via a -j option that takes, as its argument, the number of simultaneous tasks that may be spawned:
scons -j 4
builds four targets in parallel, for example.
OPTIONS¶
In general, scons supports the same command-line options as GNU Make and many of those supported by cons.
-b
-c, --clean, --remove
While clean mode removes targets rather than building them, work which is done directly in Python code in SConscript files will still be carried out. If it is important to avoid some such work from taking place in clean mode, it should be protected. An SConscript file can determine which mode is active by querying GetOption, as in the call if GetOption("clean"):
--cache-debug=file
--cache-disable, --no-cache
--cache-force, --cache-populate
--cache-readonly
--cache-show
--config=mode
auto
force
cache
-C directory, --directory=directory
-D
--debug=type[,type...]
action-timestamps
New in version 3.1.
count
duplicate
explain
findlibs
includes
$ scons --debug=includes foo.o
memoizer
memory
objects
pdb
prepare
presub
$ scons --debug=presub Building myprog.o with action(s):
$SHCC $SHCFLAGS $SHCCFLAGS $CPPFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES ...
stacktrace
time
(When scons is executed without the -j option, the elapsed wall-clock time will typically be slightly longer than the total time spent executing all the build commands, due to the SCons processing that takes place in between executing each command. When scons is executed with the -j option, and your build configuration allows good parallelization, the elapsed wall-clock time should be significantly smaller than the total time spent executing all the build commands, since multiple build commands and intervening SCons processing should take place in parallel.)
--diskcheck=type
Current available checks are:
match
Disabling some or all of these checks can provide a performance boost for large configurations, or when the configuration will check for files and/or directories across networked or shared file systems, at the slight increased risk of an incorrect build or of not handling errors gracefully.
--duplicate=ORDER
--enable-virtualenv
--experimental=feature
Current available features are: ninja (added in version 4.2), tm_v2 (added in version 4.4.1).
Caution
No Support offered for any features or tools enabled by this flag.
-f file, --file=file, --makefile=file, --sconstruct=file
-h, --help
Note that use of this option requires SCons to process the SConscript files, so syntax errors may cause the help message not to be displayed.
--hash-chunksize=KILOBYTES
The default value is to use a chunk size of 64 kilobytes, which should be appropriate for most uses.
New in version 4.2.
--hash-format=ALGORITHM
The supported list of values are: md5, sha1 and sha256. However, the Python interpreter used to run scons must have the corresponding support available in the hashlib module to use the specified algorithm.
If this option is omitted, the first supported hash format found is selected. Typically this is MD5, however, on a FIPS-compliant system using a version of Python older than 3.9, SHA1 or SHA256 is chosen as the default. Python 3.9 and onwards clients always default to MD5, even in FIPS mode.
Specifying this option changes the name of the SConsign database. The default database is .sconsign.dblite. In the presence of this option, ALGORITHM is included in the name to indicate the difference, even if the argument is md5. For example, --hash-format=sha256 uses a SConsign database named .sconsign_sha256.dblite.
New in version 4.2.
-H, --help-options
-i, --ignore-errors
-I directory, --include-dir=directory
--ignore-virtualenv
--implicit-cache
scons will not detect changes to implicit dependency search paths (e.g. $CPPPATH, $LIBPATH) that would ordinarily cause different versions of same-named files to be used.
scons will miss changes in the implicit dependencies in cases where a new implicit dependency is added earlier in the implicit dependency search path (e.g. $CPPPATH, $LIBPATH) than a current implicit dependency with the same name.
--implicit-deps-changed
--implicit-deps-unchanged
--install-sandbox=sandbox_path
--interactive
SCons interactive mode supports the following commands:
build [OPTIONS] [TARGETS] ...
The following SCons command-line options affect the build command:
--cache-debug=FILE --cache-disable, --no-cache --cache-force, --cache-populate --cache-readonly --cache-show --debug=TYPE -i, --ignore-errors -j N, --jobs=N -k, --keep-going -n, --no-exec, --just-print, --dry-run, --recon -Q -s, --silent, --quiet --taskmastertrace=FILE --tree=OPTIONS
Any other SCons command-line options that are specified do not cause errors but have no effect on the build command (mainly because they affect how the SConscript files are read, which only happens once at the beginning of interactive mode).
clean [OPTIONS] [TARGETS] ...
exit
help [COMMAND]
shell [COMMANDLINE]
version
An empty line repeats the last typed command. Command-line editing can be used if the readline module is available.
$ scons --interactive scons: Reading SConscript files ... scons: done reading SConscript files. scons>>> build -n prog scons>>> exit
-j N, --jobs=N
-k, --keep-going
-m
--max-drift=SECONDS
--md5-chunksize=KILOBYTES
Changed in version 4.2: deprecated.
-n, --no-exec, --just-print, --dry-run, --recon
Only target building is suppressed - any work in the build system that is done directly (in regular Python code) will still be carried out. You can add guards around code which should not be executed in no-exec mode by checking the value of the option at run time with GetOption:
if not GetOption("no_exec"):
# run regular instructions
The output is a best effort, as SCons cannot always precisely determine what would be built. For example, if a file generated by a builder action is also used as a source in the build, that file is not available to scan for dependencies at all in an unbuilt tree, and may contain out of date information in a previously built tree.
--no-site-dir
--package-type=type
--profile=file
-q, --question
-Q
--random
-s, --silent, --quiet
-S, --no-keep-going, --stop
--site-dir=path
The default set of site directories searched when --site-dir is not specified depends on the system platform, as follows. Users or system administrators can tune site-specific or project-specific SCons behavior by setting up a site directory in one or more of these locations. Directories are examined in the order given, from most generic ("system" directories) to most specific (in the current project), so the last-executed site_init.py file is the most specific one, giving it the chance to override everything else), and the directories are prepended to the paths, again so the last directory examined comes first in the resulting path.
Windows:
%ALLUSERSPROFILE%/scons/site_scons %LOCALAPPDATA%/scons/site_scons %APPDATA%/scons/site_scons %USERPROFILE%/.scons/site_scons ./site_scons
Note earlier versions of the documentation listed a different path for the "system" site directory, this path is still checked but its use is discouraged:
%ALLUSERSPROFILE%/Application Data/scons/site_scons
Mac OS X:
/Library/Application Support/SCons/site_scons /opt/local/share/scons/site_scons (for MacPorts) /sw/share/scons/site_scons (for Fink) $HOME/Library/Application Support/SCons/site_scons $HOME/.scons/site_scons ./site_scons
Solaris:
/opt/sfw/scons/site_scons /usr/share/scons/site_scons $HOME/.scons/site_scons ./site_scons
Linux, HPUX, and other Posix-like systems:
/usr/share/scons/site_scons $HOME/.scons/site_scons ./site_scons
--stack-size=KILOBYTES
Using a stack size that is too small may cause stack overflow errors. This usually shows up as segmentation faults that cause scons to abort before building anything. Using a stack size that is too large will cause scons to use more memory than required and may slow down the entire build process. The default value is to use a stack size of 256 kilobytes, which should be appropriate for most uses. You should not need to increase this value unless you encounter stack overflow errors.
-t, --touch
--taskmastertrace=file
--tree=type[,type...]
all
derived
linedraw
New in version 4.0.
status
prune
Multiple type choices may be specified, separated by commas:
# Prints only derived files, with status information: scons --tree=derived,status # Prints all dependencies of target, with status information # and pruning dependencies of already-visited Nodes: scons --tree=all,prune,status target
-u, --up, --search-up
-U
-v, --version
-w, --print-directory
--no-print-directory
--warn=type, --warn=no-type
all
cache-version
cache-write-error
corrupt-sconsign
dependency
deprecated
duplicate-environment
fortran-cxx-mix
future-deprecated
link
misleading-keywords
tool-qt-deprecated
missing-sconscript
no-object-count
no-parallel-support
python-version
reserved-variable
stack-size
target_not_build
-Y repository, --repository=repository, --srcdir=repository
SCONSCRIPT FILE REFERENCE¶
SConscript Files¶
The build configuration is described by one or more files, known as SConscript files. There must be at least one file for a valid build (scons will quit if it does not find one). scons by default looks for this file by the name SConstruct in the directory from which you run scons, though if necessary, also looks for alternative file names Sconstruct, sconstruct, SConstruct.py, Sconstruct.py and sconstruct.py in that order. A different file name (which can include a pathname part) may be specified via the -f option. Except for the SConstruct file, these files are not searched for automatically; you add additional configuration files to the build by calling the SConscript function. This allows parts of the build to be conditionally included or excluded at run-time depending on how scons is invoked.
Each SConscript file in a build configuration is invoked independently in a separate context. This provides necessary isolation so that different parts of the build don't accidentally step on each other. You have to be explicit about sharing information, by using the Export function or the exports argument to the SConscript function, as well as the Return function in a called SConscript file, and comsume shared information by using the Import function.
The following sections describe the various SCons facilities that can be used in SConscript files. Quick links:
Construction Environments¶
A Construction Environment is the basic means by which you communicate build information to SCons. A new construction environment is created using the Environment function:
env = Environment()
Construction environment attributes called Construction Variables may be set either by specifying them as keyword arguments when the object is created or by assigning them a value after the object is created. These two are nominally equivalent:
env = Environment(FOO='foo') env['FOO'] = 'foo'
Note that certain settings which affect tool detection are referenced only when the tools are initializided, so you either need either to supply them as part of the call to Environment, or defer tool initialization. For example, initializing the Microsoft Visual C++ version you wish to use:
# initializes msvc to v14.1
env = Environment(MSVC_VERSION="14.1")
env = Environment()
# msvc tool was initialized to default, does not reinitialize
env['MSVC_VERSION'] = "14.1"
env = Environment(tools=[])
env['MSVC_VERSION'] = "14.1"
# msvc tool initialization was deferred, so will pick up new value
env.Tool('default')
As a convenience, construction variables may also be set or modified by the parse_flags keyword argument during object creation, which has the effect of the env.MergeFlags method being applied to the argument value after all other processing is completed. This is useful either if the exact content of the flags is unknown (for example, read from a control file) or if the flags need to be distributed to a number of construction variables. env.ParseFlags describes how these arguments are distributed to construction variables.
env = Environment(parse_flags='-Iinclude -DEBUG -lm')
This example adds 'include' to the $CPPPATH construction variable, 'EBUG' to $CPPDEFINES, and 'm' to $LIBS.
An existing construction environment can be duplicated by calling the env.Clone method. Without arguments, it will be a copy with the same settings. Otherwise, env.Clone takes the same arguments as Environment, and uses the arguments to create a modified copy.
SCons provides a special construction environment called the Default Environment. The default environment is used only for global functions, that is, construction activities called without the context of a regular construction environment. See DefaultEnvironment for more information.
By default, a new construction environment is initialized with a set of builder methods and construction variables that are appropriate for the current platform. The optional platform keyword argument may be used to specify that the construction environment should be initialized for a different platform:
env = Environment(platform='cygwin')
Specifying a platform initializes the appropriate construction variables in the environment to use and generate file names with prefixes and suffixes appropriate for that platform.
Note that the win32 platform adds the SystemDrive and SystemRoot variables from the user's external environment to the construction environment's ENV dictionary. This is so that any executed commands that use sockets to connect with other systems will work on Windows systems.
The platform argument may be a string value representing one of the pre-defined platforms (aix, cygwin, darwin, hpux, irix, os2, posix, sunos or win32), or it may be be a callable platform object returned by a call to Platform selecting a pre-defined platform, or it may be a user-supplied callable, in which case the Environment method will call it to update the new construction environment:
def my_platform(env):
env['VAR'] = 'xyzzy' env = Environment(platform=my_platform)
Note that supplying a non-default platform or custom fuction for initialization may bypass settings that should happen for the host system and should be used with care. It is most useful in the case where the platform is an alternative for the one that would be auto-detected, such as platform="cygwin" on a system which would otherwise identify as win32.
The optional tools and toolpath keyword arguments affect the way tools available to the environment are initialized. See the section called “Tools” for details.
The optional variables keyword argument allows passing a Variables object which will be used in the initialization of the construction environment See the section called “Command-Line Construction Variables” for details.
Tools¶
SCons has a large number of predefined tool modules (more properly, tool specification modules) which are used to help initialize the construction environment. An SCons tool is only responsible for setup. For example, if an SConscript file declares the need to construct an object file from a C-language source file by calling the Object builder, then a tool representing an available C compiler needs to have run first, to set up that builder and all the construction variables it needs in the associated construction environment; the tool itself is not called in the process of the build. Normally this happens invisibly as scons has per-platform lists of default tools, and it steps through those tools, calling the ones which are actually applicable, skipping those where necessary programs are not installed on the build system, or other preconditions are not met.
A specific set of tools with which to initialize an environment when creating it may be specified using the optional keyword argument tools, which takes a list of tool names. This is useful to override the defaults, to specify non-default built-in tools, and to supply added tools:
env = Environment(tools=['msvc', 'lex'])
Tools can also be directly called by using the Tool method (see below).
The tools argument overrides the default tool list, it does not add to it, so be sure to include all the tools you need. For example if you are building a c/c++ program you must specify a tool for at least a compiler and a linker, as in tools=['clang', 'link']. The tool name 'default' can be used to retain the default list.
If no tools argument is specified, or if tools includes 'default', then scons will auto-detect usable tools, using the execution environment value of PATH (that is, env['ENV']['PATH'] - the external evironment PATH from os.environ is not used) for looking up any backing programs, and the platform name in effect to determine the default tools for that platform. Changing the PATH variable after the construction environment is constructed will not cause the tools to be re-detected.
Additional tools can be added, see the Extending SCons section and specifically Tool Modules.
SCons supports the following tool specifications out of the box:
386asm
Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.
Uses: $CC, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.
aixc++
Sets: $CXX, $CXXVERSION, $SHCXX, $SHOBJSUFFIX.
aixcc
Sets: $CC, $CCVERSION, $SHCC.
aixf77
Sets: $F77, $SHF77.
aixlink
Sets: $LINKFLAGS, $SHLIBSUFFIX, $SHLINKFLAGS.
applelink
Sets: $APPLELINK_COMPATIBILITY_VERSION, $APPLELINK_CURRENT_VERSION, $APPLELINK_NO_COMPATIBILITY_VERSION, $APPLELINK_NO_CURRENT_VERSION, $FRAMEWORKPATHPREFIX, $LDMODULECOM, $LDMODULEFLAGS, $LDMODULEPREFIX, $LDMODULESUFFIX, $LINKCOM, $SHLINKCOM, $SHLINKFLAGS, $_APPLELINK_COMPATIBILITY_VERSION, $_APPLELINK_CURRENT_VERSION, $_FRAMEWORKPATH, $_FRAMEWORKS.
Uses: $FRAMEWORKSFLAGS.
ar
Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX, $RANLIB, $RANLIBCOM, $RANLIBFLAGS.
as
Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.
Uses: $CC, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.
bcc32
Sets: $CC, $CCCOM, $CCFLAGS, $CFILESUFFIX, $CFLAGS, $CPPDEFPREFIX, $CPPDEFSUFFIX, $INCPREFIX, $INCSUFFIX, $SHCC, $SHCCCOM, $SHCCFLAGS, $SHCFLAGS, $SHOBJSUFFIX.
Uses: $_CPPDEFFLAGS, $_CPPINCFLAGS.
cc
Sets: $CC, $CCCOM, $CCDEPFLAGS, $CCFLAGS, $CFILESUFFIX, $CFLAGS, $CPPDEFPREFIX, $CPPDEFSUFFIX, $FRAMEWORKPATH, $FRAMEWORKS, $INCPREFIX, $INCSUFFIX, $SHCC, $SHCCCOM, $SHCCFLAGS, $SHCFLAGS, $SHOBJSUFFIX.
Uses: $CCCOMSTR, $PLATFORM, $SHCCCOMSTR.
clang
Sets: $CC, $CCDEPFLAGS, $CCVERSION, $SHCCFLAGS.
clangxx
Sets: $CXX, $CXXVERSION, $SHCXXFLAGS, $SHOBJSUFFIX, $STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME.
compilation_db
Sets: $COMPILATIONDB_COMSTR, $COMPILATIONDB_PATH_FILTER, $COMPILATIONDB_USE_ABSPATH.
cvf
Sets: $FORTRAN, $FORTRANCOM, $FORTRANMODDIR, $FORTRANMODDIRPREFIX, $FORTRANMODDIRSUFFIX, $FORTRANPPCOM, $OBJSUFFIX, $SHFORTRANCOM, $SHFORTRANPPCOM.
Uses: $CPPFLAGS, $FORTRANFLAGS, $SHFORTRANFLAGS, $_CPPDEFFLAGS, $_FORTRANINCFLAGS, $_FORTRANMODFLAG.
cXX
Sets: $CPPDEFPREFIX, $CPPDEFSUFFIX, $CXX, $CXXCOM, $CXXFILESUFFIX, $CXXFLAGS, $INCPREFIX, $INCSUFFIX, $OBJSUFFIX, $SHCXX, $SHCXXCOM, $SHCXXFLAGS, $SHOBJSUFFIX.
Uses: $CXXCOMSTR, $SHCXXCOMSTR.
cyglink
Sets: $IMPLIBPREFIX, $IMPLIBSUFFIX, $LDMODULEVERSIONFLAGS, $LINKFLAGS, $RPATHPREFIX, $RPATHSUFFIX, $SHLIBPREFIX, $SHLIBSUFFIX, $SHLIBVERSIONFLAGS, $SHLINKCOM, $SHLINKFLAGS, $_LDMODULEVERSIONFLAGS, $_SHLIBVERSIONFLAGS.
default
The list of tools selected by default is not static, but is dependent both on the platform and on the software installed on the platform. Some tools will not initialize if an underlying command is not found, and some tools are selected from a list of choices on a first-found basis. The finished tool list can be examined by inspecting the $TOOLS construction variable in the construction environment.
On all platforms, the tools from the following list are selected if their respective conditions are met: filesystem;, wix, lex, yacc, rpcgen, swig, jar, javac, javah, rmic, dvipdf, dvips, gs, tex, latex, pdflatex, pdftex, tar, zip, textfile.
On Linux systems, the default tools list selects (first-found): a C compiler from gcc, intelc, icc, cc; a C++ compiler from g++, intelc, icc, cXX; an assembler from gas, nasm, masm; a linker from gnulink, ilink; a Fortran compiler from gfortran, g77, ifort, ifl, f95, f90, f77; and a static archiver ar. It also selects all found from the list m4 rpm.
On Windows systems, the default tools list selects (first-found): a C compiler from msvc, mingw, gcc, intelc, icl, icc, cc, bcc32; a C++ compiler from msvc, intelc, icc, g++, cXX, bcc32; an assembler from masm, nasm, gas, 386asm; a linker from mslink, gnulink, ilink, linkloc, ilink32; a Fortran compiler from gfortran, g77, ifl, cvf, f95, f90, fortran; and a static archiver from mslib, ar, tlib; It also selects all found from the list msvs, midl.
On MacOS systems, the default tools list selects (first-found): a C compiler from gcc, cc; a C++ compiler from g++, cXX; an assembler as; a linker from applelink, gnulink; a Fortran compiler from gfortran, f95, f90, g77; and a static archiver ar. It also selects all found from the list m4, rpm.
Default lists for other platforms can be found by examining the scons source code (see SCons/Tool/__init__.py).
dmd
Sets: $DC, $DCOM, $DDEBUG, $DDEBUGPREFIX, $DDEBUGSUFFIX, $DFILESUFFIX, $DFLAGPREFIX, $DFLAGS, $DFLAGSUFFIX, $DINCPREFIX, $DINCSUFFIX, $DLIB, $DLIBCOM, $DLIBDIRPREFIX, $DLIBDIRSUFFIX, $DLIBFLAGPREFIX, $DLIBFLAGSUFFIX, $DLIBLINKPREFIX, $DLIBLINKSUFFIX, $DLINK, $DLINKCOM, $DLINKFLAGPREFIX, $DLINKFLAGS, $DLINKFLAGSUFFIX, $DPATH, $DRPATHPREFIX, $DRPATHSUFFIX, $DVERPREFIX, $DVERSIONS, $DVERSUFFIX, $SHDC, $SHDCOM, $SHDLIBVERSIONFLAGS, $SHDLINK, $SHDLINKCOM, $SHDLINKFLAGS.
docbook
Implicit dependencies to images and XIncludes are detected automatically if you meet the HTML requirements. The additional stylesheet utils/xmldepend.xsl by Paul DuBois is used for this purpose.
Note, that there is no support for XML catalog resolving offered! This tool calls the XSLT processors and PDF renderers with the stylesheets you specified, that's it. The rest lies in your hands and you still have to know what you're doing when resolving names via a catalog.
For activating the tool "docbook", you have to add its name to the Environment constructor, like this
env = Environment(tools=['docbook'])
On its startup, the docbook tool tries to find a required xsltproc processor, and a PDF renderer, e.g. fop. So make sure that these are added to your system's environment PATH and can be called directly without specifying their full path.
For the most basic processing of Docbook to HTML, you need to have installed
Rendering to PDF requires you to have one of the applications fop or xep installed.
Creating a HTML or PDF document is very simple and straightforward. Say
env = Environment(tools=['docbook'])
env.DocbookHtml('manual.html', 'manual.xml')
env.DocbookPdf('manual.pdf', 'manual.xml')
to get both outputs from your XML source manual.xml. As a shortcut, you can give the stem of the filenames alone, like this:
env = Environment(tools=['docbook'])
env.DocbookHtml('manual')
env.DocbookPdf('manual')
and get the same result. Target and source lists are also supported:
env = Environment(tools=['docbook']) env.DocbookHtml(['manual.html','reference.html'], ['manual.xml','reference.xml'])
or even
env = Environment(tools=['docbook']) env.DocbookHtml(['manual','reference'])
Important
Whenever you leave out the list of sources, you may not specify a file extension! The Tool uses the given names as file stems, and adds the suffixes for target and source files accordingly.
The Builders DocbookHtmlChunked, DocbookHtmlhelp and DocbookSlidesHtml are special, in that:
As a result, there is simply no use in specifying a target HTML name. So the basic syntax for these builders is always:
env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('manual')
If you want to use a specific XSL file, you can set the additional xsl parameter to your Builder call as follows:
env.DocbookHtml('other.html', 'manual.xml', xsl='html.xsl')
Since this may get tedious if you always use the same local naming for your customized XSL files, e.g. html.xsl for HTML and pdf.xsl for PDF output, a set of variables for setting the default XSL name is provided. These are:
DOCBOOK_DEFAULT_XSL_HTML DOCBOOK_DEFAULT_XSL_HTMLCHUNKED DOCBOOK_DEFAULT_XSL_HTMLHELP DOCBOOK_DEFAULT_XSL_PDF DOCBOOK_DEFAULT_XSL_EPUB DOCBOOK_DEFAULT_XSL_MAN DOCBOOK_DEFAULT_XSL_SLIDESPDF DOCBOOK_DEFAULT_XSL_SLIDESHTML
and you can set them when constructing your environment:
env = Environment(
tools=['docbook'],
DOCBOOK_DEFAULT_XSL_HTML='html.xsl',
DOCBOOK_DEFAULT_XSL_PDF='pdf.xsl', ) env.DocbookHtml('manual') # now uses html.xsl
Sets: $DOCBOOK_DEFAULT_XSL_EPUB, $DOCBOOK_DEFAULT_XSL_HTML, $DOCBOOK_DEFAULT_XSL_HTMLCHUNKED, $DOCBOOK_DEFAULT_XSL_HTMLHELP, $DOCBOOK_DEFAULT_XSL_MAN, $DOCBOOK_DEFAULT_XSL_PDF, $DOCBOOK_DEFAULT_XSL_SLIDESHTML, $DOCBOOK_DEFAULT_XSL_SLIDESPDF, $DOCBOOK_FOP, $DOCBOOK_FOPCOM, $DOCBOOK_FOPFLAGS, $DOCBOOK_XMLLINT, $DOCBOOK_XMLLINTCOM, $DOCBOOK_XMLLINTFLAGS, $DOCBOOK_XSLTPROC, $DOCBOOK_XSLTPROCCOM, $DOCBOOK_XSLTPROCFLAGS, $DOCBOOK_XSLTPROCPARAMS.
Uses: $DOCBOOK_FOPCOMSTR, $DOCBOOK_XMLLINTCOMSTR, $DOCBOOK_XSLTPROCCOMSTR.
dvi
dvipdf
Sets: $DVIPDF, $DVIPDFCOM, $DVIPDFFLAGS.
Uses: $DVIPDFCOMSTR.
dvips
Sets: $DVIPS, $DVIPSFLAGS, $PSCOM, $PSPREFIX, $PSSUFFIX.
Uses: $PSCOMSTR.
f03
Sets: $F03, $F03COM, $F03FLAGS, $F03PPCOM, $SHF03, $SHF03COM, $SHF03FLAGS, $SHF03PPCOM, $_F03INCFLAGS.
Uses: $F03COMSTR, $F03PPCOMSTR, $FORTRANCOMMONFLAGS, $SHF03COMSTR, $SHF03PPCOMSTR.
f08
Sets: $F08, $F08COM, $F08FLAGS, $F08PPCOM, $SHF08, $SHF08COM, $SHF08FLAGS, $SHF08PPCOM, $_F08INCFLAGS.
Uses: $F08COMSTR, $F08PPCOMSTR, $FORTRANCOMMONFLAGS, $SHF08COMSTR, $SHF08PPCOMSTR.
f77
Sets: $F77, $F77COM, $F77FILESUFFIXES, $F77FLAGS, $F77PPCOM, $F77PPFILESUFFIXES, $FORTRAN, $FORTRANCOM, $FORTRANFLAGS, $SHF77, $SHF77COM, $SHF77FLAGS, $SHF77PPCOM, $SHFORTRAN, $SHFORTRANCOM, $SHFORTRANFLAGS, $SHFORTRANPPCOM, $_F77INCFLAGS.
Uses: $F77COMSTR, $F77PPCOMSTR, $FORTRANCOMMONFLAGS, $FORTRANCOMSTR, $FORTRANFLAGS, $FORTRANPPCOMSTR, $SHF77COMSTR, $SHF77PPCOMSTR, $SHFORTRANCOMSTR, $SHFORTRANFLAGS, $SHFORTRANPPCOMSTR.
f90
Sets: $F90, $F90COM, $F90FLAGS, $F90PPCOM, $SHF90, $SHF90COM, $SHF90FLAGS, $SHF90PPCOM, $_F90INCFLAGS.
Uses: $F90COMSTR, $F90PPCOMSTR, $FORTRANCOMMONFLAGS, $SHF90COMSTR, $SHF90PPCOMSTR.
f95
Sets: $F95, $F95COM, $F95FLAGS, $F95PPCOM, $SHF95, $SHF95COM, $SHF95FLAGS, $SHF95PPCOM, $_F95INCFLAGS.
Uses: $F95COMSTR, $F95PPCOMSTR, $FORTRANCOMMONFLAGS, $SHF95COMSTR, $SHF95PPCOMSTR.
fortran
Sets: $FORTRAN, $FORTRANCOM, $FORTRANFLAGS, $SHFORTRAN, $SHFORTRANCOM, $SHFORTRANFLAGS, $SHFORTRANPPCOM.
Uses: $CPPFLAGS, $FORTRANCOMSTR, $FORTRANPPCOMSTR, $SHFORTRANCOMSTR, $SHFORTRANPPCOMSTR, $_CPPDEFFLAGS.
g++
Sets: $CXX, $CXXVERSION, $SHCXXFLAGS, $SHOBJSUFFIX.
g77
Sets: $F77, $F77COM, $F77FILESUFFIXES, $F77PPCOM, $F77PPFILESUFFIXES, $FORTRAN, $FORTRANCOM, $FORTRANPPCOM, $SHF77, $SHF77COM, $SHF77FLAGS, $SHF77PPCOM, $SHFORTRAN, $SHFORTRANCOM, $SHFORTRANFLAGS, $SHFORTRANPPCOM.
Uses: $F77FLAGS, $FORTRANCOMMONFLAGS, $FORTRANFLAGS.
gas
Sets: $AS.
gcc
Sets: $CC, $CCDEPFLAGS, $CCVERSION, $SHCCFLAGS.
gdc
Sets: $DC, $DCOM, $DDEBUG, $DDEBUGPREFIX, $DDEBUGSUFFIX, $DFILESUFFIX, $DFLAGPREFIX, $DFLAGS, $DFLAGSUFFIX, $DINCPREFIX, $DINCSUFFIX, $DLIB, $DLIBCOM, $DLIBDIRPREFIX, $DLIBDIRSUFFIX, $DLIBFLAGPREFIX, $DLIBFLAGSUFFIX, $DLIBLINKPREFIX, $DLIBLINKSUFFIX, $DLINK, $DLINKCOM, $DLINKFLAGPREFIX, $DLINKFLAGS, $DLINKFLAGSUFFIX, $DPATH, $DRPATHPREFIX, $DRPATHSUFFIX, $DVERPREFIX, $DVERSIONS, $DVERSUFFIX, $SHDC, $SHDCOM, $SHDLIBVERSIONFLAGS, $SHDLINK, $SHDLINKCOM, $SHDLINKFLAGS.
gettext
When you enable gettext, it internally loads all abovementioned tools, so you're encouraged to see their individual documentation.
Each of the above tools provides its own builder(s) which may be used to perform particular activities related to software internationalization. You may be however interested in top-level Translate builder.
To use gettext tools add 'gettext' tool to your environment:
env = Environment( tools = ['default', 'gettext'] )
gfortran
Sets: $F77, $F90, $F95, $FORTRAN, $SHF77, $SHF77FLAGS, $SHF90, $SHF90FLAGS, $SHF95, $SHF95FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.
gnulink
Sets: $LDMODULEVERSIONFLAGS, $RPATHPREFIX, $RPATHSUFFIX, $SHLIBVERSIONFLAGS, $SHLINKFLAGS, $_LDMODULESONAME, $_SHLIBSONAME.
gs
Sets: $GS, $GSCOM, $GSFLAGS.
Uses: $GSCOMSTR.
hpc++
hpcc
Sets: $CXX, $CXXVERSION, $SHCXXFLAGS.
hplink
Sets: $LINKFLAGS, $SHLIBSUFFIX, $SHLINKFLAGS.
icc
Sets: $CC, $CCCOM, $CFILESUFFIX, $CPPDEFPREFIX, $CPPDEFSUFFIX, $CXXCOM, $CXXFILESUFFIX, $INCPREFIX, $INCSUFFIX.
Uses: $CCFLAGS, $CFLAGS, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.
icl
ifl
Sets: $FORTRAN, $FORTRANCOM, $FORTRANPPCOM, $SHFORTRANCOM, $SHFORTRANPPCOM.
Uses: $CPPFLAGS, $FORTRANFLAGS, $_CPPDEFFLAGS, $_FORTRANINCFLAGS.
ifort
Sets: $F77, $F90, $F95, $FORTRAN, $SHF77, $SHF77FLAGS, $SHF90, $SHF90FLAGS, $SHF95, $SHF95FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.
ilink
Sets: $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM, $LINKFLAGS.
ilink32
Sets: $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM, $LINKFLAGS.
install
Sets: $INSTALL, $INSTALLSTR.
intelc
Sets: $AR, $CC, $CXX, $INTEL_C_COMPILER_VERSION, $LINK.
jar
Sets: $JAR, $JARCOM, $JARFLAGS, $JARSUFFIX.
Uses: $JARCOMSTR.
javac
Sets: $JAVABOOTCLASSPATH, $JAVAC, $JAVACCOM, $JAVACFLAGS, $JAVACLASSPATH, $JAVACLASSSUFFIX, $JAVAINCLUDES, $JAVASOURCEPATH, $JAVASUFFIX.
Uses: $JAVACCOMSTR.
javah
Sets: $JAVACLASSSUFFIX, $JAVAH, $JAVAHCOM, $JAVAHFLAGS.
Uses: $JAVACLASSPATH, $JAVAHCOMSTR.
latex
Sets: $LATEX, $LATEXCOM, $LATEXFLAGS.
Uses: $LATEXCOMSTR.
ldc
Sets: $DC, $DCOM, $DDEBUG, $DDEBUGPREFIX, $DDEBUGSUFFIX, $DFILESUFFIX, $DFLAGPREFIX, $DFLAGS, $DFLAGSUFFIX, $DINCPREFIX, $DINCSUFFIX, $DLIB, $DLIBCOM, $DLIBDIRPREFIX, $DLIBDIRSUFFIX, $DLIBFLAGPREFIX, $DLIBFLAGSUFFIX, $DLIBLINKPREFIX, $DLIBLINKSUFFIX, $DLINK, $DLINKCOM, $DLINKFLAGPREFIX, $DLINKFLAGS, $DLINKFLAGSUFFIX, $DPATH, $DRPATHPREFIX, $DRPATHSUFFIX, $DVERPREFIX, $DVERSIONS, $DVERSUFFIX, $SHDC, $SHDCOM, $SHDLIBVERSIONFLAGS, $SHDLINK, $SHDLINKCOM, $SHDLINKFLAGS.
lex
Sets: $LEX, $LEXCOM, $LEXFLAGS, $LEXUNISTD.
Uses: $LEXCOMSTR, $LEXFLAGS, $LEX_HEADER_FILE, $LEX_TABLES_FILE.
link
Sets: $LDMODULE, $LDMODULECOM, $LDMODULEFLAGS, $LDMODULENOVERSIONSYMLINKS, $LDMODULEPREFIX, $LDMODULESUFFIX, $LDMODULEVERSION, $LDMODULEVERSIONFLAGS, $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM, $LINKFLAGS, $SHLIBSUFFIX, $SHLINK, $SHLINKCOM, $SHLINKFLAGS, $__LDMODULEVERSIONFLAGS, $__SHLIBVERSIONFLAGS.
Uses: $LDMODULECOMSTR, $LINKCOMSTR, $SHLINKCOMSTR.
linkloc
Sets: $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM, $LINKFLAGS, $SHLINK, $SHLINKCOM, $SHLINKFLAGS.
Uses: $LINKCOMSTR, $SHLINKCOMSTR.
m4
Sets: $M4, $M4COM, $M4FLAGS.
Uses: $M4COMSTR.
masm
Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.
Uses: $ASCOMSTR, $ASPPCOMSTR, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.
midl
Sets: $MIDL, $MIDLCOM, $MIDLFLAGS.
Uses: $MIDLCOMSTR.
mingw
Sets: $AS, $CC, $CXX, $LDMODULECOM, $LIBPREFIX, $LIBSUFFIX, $OBJSUFFIX, $RC, $RCCOM, $RCFLAGS, $RCINCFLAGS, $RCINCPREFIX, $RCINCSUFFIX, $SHCCFLAGS, $SHCXXFLAGS, $SHLINKCOM, $SHLINKFLAGS, $SHOBJSUFFIX, $WINDOWSDEFPREFIX, $WINDOWSDEFSUFFIX.
Uses: $RCCOMSTR, $SHLINKCOMSTR.
msgfmt
Sets: $MOSUFFIX, $MSGFMT, $MSGFMTCOM, $MSGFMTCOMSTR, $MSGFMTFLAGS, $POSUFFIX.
Uses: $LINGUAS_FILE.
msginit
Sets: $MSGINIT, $MSGINITCOM, $MSGINITCOMSTR, $MSGINITFLAGS, $POAUTOINIT, $POCREATE_ALIAS, $POSUFFIX, $POTSUFFIX, $_MSGINITLOCALE.
Uses: $LINGUAS_FILE, $POAUTOINIT, $POTDOMAIN.
msgmerge
Sets: $MSGMERGE, $MSGMERGECOM, $MSGMERGECOMSTR, $MSGMERGEFLAGS, $POSUFFIX, $POTSUFFIX, $POUPDATE_ALIAS.
Uses: $LINGUAS_FILE, $POAUTOINIT, $POTDOMAIN.
mslib
Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX.
Uses: $ARCOMSTR.
mslink
Sets: $LDMODULE, $LDMODULECOM, $LDMODULEFLAGS, $LDMODULEPREFIX, $LDMODULESUFFIX, $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM, $LINKFLAGS, $REGSVR, $REGSVRCOM, $REGSVRFLAGS, $SHLINK, $SHLINKCOM, $SHLINKFLAGS, $WINDOWSDEFPREFIX, $WINDOWSDEFSUFFIX, $WINDOWSEXPPREFIX, $WINDOWSEXPSUFFIX, $WINDOWSPROGMANIFESTPREFIX, $WINDOWSPROGMANIFESTSUFFIX, $WINDOWSSHLIBMANIFESTPREFIX, $WINDOWSSHLIBMANIFESTSUFFIX, $WINDOWS_INSERT_DEF.
Uses: $LDMODULECOMSTR, $LINKCOMSTR, $REGSVRCOMSTR, $SHLINKCOMSTR.
mssdk
Uses: $MSSDK_DIR, $MSSDK_VERSION, $MSVS_VERSION.
msvc
Sets: $BUILDERS, $CC, $CCCOM, $CCDEPFLAGS, $CCFLAGS, $CCPCHFLAGS, $CCPDBFLAGS, $CFILESUFFIX, $CFLAGS, $CPPDEFPREFIX, $CPPDEFSUFFIX, $CXX, $CXXCOM, $CXXFILESUFFIX, $CXXFLAGS, $INCPREFIX, $INCSUFFIX, $OBJPREFIX, $OBJSUFFIX, $PCHCOM, $PCHPDBFLAGS, $RC, $RCCOM, $RCFLAGS, $SHCC, $SHCCCOM, $SHCCFLAGS, $SHCFLAGS, $SHCXX, $SHCXXCOM, $SHCXXFLAGS, $SHOBJPREFIX, $SHOBJSUFFIX.
Uses: $CCCOMSTR, $CXXCOMSTR, $MSVC_NOTFOUND_POLICY, $MSVC_SCRIPTERROR_POLICY, $MSVC_SCRIPT_ARGS, $MSVC_SDK_VERSION, $MSVC_SPECTRE_LIBS, $MSVC_TOOLSET_VERSION, $MSVC_USE_SCRIPT, $MSVC_USE_SCRIPT_ARGS, $MSVC_USE_SETTINGS, $MSVC_VERSION, $PCH, $PCHSTOP, $PDB, $SHCCCOMSTR, $SHCXXCOMSTR.
msvs
Sets: $MSVSBUILDCOM, $MSVSCLEANCOM, $MSVSENCODING, $MSVSPROJECTCOM, $MSVSREBUILDCOM, $MSVSSCONS, $MSVSSCONSCOM, $MSVSSCONSCRIPT, $MSVSSCONSFLAGS, $MSVSSOLUTIONCOM.
mwcc
Sets: $CC, $CCCOM, $CFILESUFFIX, $CPPDEFPREFIX, $CPPDEFSUFFIX, $CXX, $CXXCOM, $CXXFILESUFFIX, $INCPREFIX, $INCSUFFIX, $MWCW_VERSION, $MWCW_VERSIONS, $SHCC, $SHCCCOM, $SHCCFLAGS, $SHCFLAGS, $SHCXX, $SHCXXCOM, $SHCXXFLAGS.
Uses: $CCCOMSTR, $CXXCOMSTR, $SHCCCOMSTR, $SHCXXCOMSTR.
mwld
Sets: $AR, $ARCOM, $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM, $SHLINK, $SHLINKCOM, $SHLINKFLAGS.
nasm
Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.
Uses: $ASCOMSTR, $ASPPCOMSTR.
ninja
Note
This is an experimental feature. This functionality is subject to change and/or removal without a deprecation cycle.
Uses: $AR, $ARCOM, $ARFLAGS, $CC, $CCCOM, $CCDEPFLAGS, $CCFLAGS, $CXX, $CXXCOM, $ESCAPE, $LINK, $LINKCOM, $PLATFORM, $PRINT_CMD_LINE_FUNC, $PROGSUFFIX, $RANLIB, $RANLIBCOM, $SHCCCOM, $SHCXXCOM, $SHLINK, $SHLINKCOM.
packaging
Sets: $PDFPREFIX, $PDFSUFFIX.
pdflatex
Sets: $LATEXRETRIES, $PDFLATEX, $PDFLATEXCOM, $PDFLATEXFLAGS.
Uses: $PDFLATEXCOMSTR.
pdftex
Sets: $LATEXRETRIES, $PDFLATEX, $PDFLATEXCOM, $PDFLATEXFLAGS, $PDFTEX, $PDFTEXCOM, $PDFTEXFLAGS.
Uses: $PDFLATEXCOMSTR, $PDFTEXCOMSTR.
python
Available since scons 4.0..
qt
qt3
Note
This tool is only suitable for building targeted to Qt3, which is obsolete (the tool is deprecated since 4.3, and was renamed to qt3 in 4.5.0. ). There are contributed tools for Qt4 and Qt5, see https://github.com/SCons/scons-contrib[1]. Qt4 has also passed end of life for standard support (in Dec 2015).
In addition, the construction variables $CPPPATH, $LIBPATH and $LIBS may be modified and the variables $PROGEMITTER, $SHLIBEMITTER and $LIBEMITTER are modified. Because the build-performance is affected when using this tool, you have to explicitly specify it at Environment creation:
Environment(tools=['default','qt3'])
The qt3 tool supports the following operations:
Automatic moc file generation from header files. You do not have to specify moc files explicitly, the tool does it for you. However, there are a few preconditions to do so: Your header file must have the same filebase as your implementation file and must stay in the same directory. It must have one of the suffixes .h, .hpp, .H, .hxx, .hh. You can turn off automatic moc file generation by setting $QT3_AUTOSCAN to False. See also the corresponding Moc Builder.
Automatic moc file generation from C++ files. As described in the Qt documentation, include the moc file at the end of the C++ file. Note that you have to include the file, which is generated by the transformation ${QT3_MOCCXXPREFIX}<basename>${QT3_MOCCXXSUFFIX}, by default <basename>.mo. A warning is generated after building the moc file if you do not include the correct file. If you are using VariantDir, you may need to specify duplicate=True. You can turn off automatic moc file generation by setting $QT3_AUTOSCAN to False. See also the corresponding Moc Builder.
Automatic handling of .ui files. The implementation files generated from .ui files are handled much the same as yacc or lex files. Each .ui file given as a source of Program, Library or SharedLibrary will generate three files: the declaration file, the implementation file and a moc file. Because there are also generated headers, you may need to specify duplicate=True in calls to VariantDir. See also the corresponding Uic Builder.
Sets: $QT3DIR, $QT3_AUTOSCAN, $QT3_BINPATH, $QT3_CPPPATH, $QT3_LIB, $QT3_LIBPATH, $QT3_MOC, $QT3_MOCCXXPREFIX, $QT3_MOCCXXSUFFIX, $QT3_MOCFROMCXXCOM, $QT3_MOCFROMCXXFLAGS, $QT3_MOCFROMHCOM, $QT3_MOCFROMHFLAGS, $QT3_MOCHPREFIX, $QT3_MOCHSUFFIX, $QT3_UIC, $QT3_UICCOM, $QT3_UICDECLFLAGS, $QT3_UICDECLPREFIX, $QT3_UICDECLSUFFIX, $QT3_UICIMPLFLAGS, $QT3_UICIMPLPREFIX, $QT3_UICIMPLSUFFIX, $QT3_UISUFFIX.
Uses: $QT3DIR.
rmic
Sets: $JAVACLASSSUFFIX, $RMIC, $RMICCOM, $RMICFLAGS.
Uses: $RMICCOMSTR.
rpcgen
Sets: $RPCGEN, $RPCGENCLIENTFLAGS, $RPCGENFLAGS, $RPCGENHEADERFLAGS, $RPCGENSERVICEFLAGS, $RPCGENXDRFLAGS.
sgiar
Sets: $AR, $ARCOMSTR, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX, $SHLINK, $SHLINKFLAGS.
Uses: $ARCOMSTR, $SHLINKCOMSTR.
sgic++
Sets: $CXX, $CXXFLAGS, $SHCXX, $SHOBJSUFFIX.
sgicc
Sets: $CXX, $SHOBJSUFFIX.
sgilink
Sets: $LINK, $RPATHPREFIX, $RPATHSUFFIX, $SHLINKFLAGS.
sunar
Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX.
Uses: $ARCOMSTR.
sunc++
Sets: $CXX, $CXXVERSION, $SHCXX, $SHCXXFLAGS, $SHOBJPREFIX, $SHOBJSUFFIX.
suncc
Sets: $CXX, $SHCCFLAGS, $SHOBJPREFIX, $SHOBJSUFFIX.
sunf77
Sets: $F77, $FORTRAN, $SHF77, $SHF77FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.
sunf90
Sets: $F90, $FORTRAN, $SHF90, $SHF90FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.
sunf95
Sets: $F95, $FORTRAN, $SHF95, $SHF95FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.
sunlink
Sets: $RPATHPREFIX, $RPATHSUFFIX, $SHLINKFLAGS.
swig
Sets: $SWIG, $SWIGCFILESUFFIX, $SWIGCOM, $SWIGCXXFILESUFFIX, $SWIGDIRECTORSUFFIX, $SWIGFLAGS, $SWIGINCPREFIX, $SWIGINCSUFFIX, $SWIGPATH, $SWIGVERSION, $_SWIGINCFLAGS.
Uses: $SWIGCOMSTR.
tar
Sets: $TAR, $TARCOM, $TARFLAGS, $TARSUFFIX.
Uses: $TARCOMSTR.
tex
Sets: $BIBTEX, $BIBTEXCOM, $BIBTEXFLAGS, $LATEX, $LATEXCOM, $LATEXFLAGS, $MAKEINDEX, $MAKEINDEXCOM, $MAKEINDEXFLAGS, $TEX, $TEXCOM, $TEXFLAGS.
Uses: $BIBTEXCOMSTR, $LATEXCOMSTR, $MAKEINDEXCOMSTR, $TEXCOMSTR.
textfile
Sets: $FILE_ENCODING, $LINESEPARATOR, $SUBSTFILEPREFIX, $SUBSTFILESUFFIX, $TEXTFILEPREFIX, $TEXTFILESUFFIX.
Uses: $SUBST_DICT.
tlib
Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX.
Uses: $ARCOMSTR.
xgettext
Sets: $POTSUFFIX, $POTUPDATE_ALIAS, $XGETTEXTCOM, $XGETTEXTCOMSTR, $XGETTEXTFLAGS, $XGETTEXTFROM, $XGETTEXTFROMPREFIX, $XGETTEXTFROMSUFFIX, $XGETTEXTPATH, $XGETTEXTPATHPREFIX, $XGETTEXTPATHSUFFIX, $_XGETTEXTDOMAIN, $_XGETTEXTFROMFLAGS, $_XGETTEXTPATHFLAGS.
Uses: $POTDOMAIN.
yacc
Sets: $YACC, $YACCCOM, $YACCFLAGS, $YACCHFILESUFFIX, $YACCHXXFILESUFFIX, $YACCVCGFILESUFFIX.
Uses: $YACCCOMSTR, $YACCFLAGS, $YACC_GRAPH_FILE, $YACC_HEADER_FILE.
zip
Sets: $ZIP, $ZIPCOM, $ZIPCOMPRESSION, $ZIPFLAGS, $ZIPSUFFIX.
Uses: $ZIPCOMSTR.
Builder Methods¶
You tell SCons what to build by calling Builders, functions which take particular action(s) to produce target(s) of a particular type (conventionally hinted at by the builder name, e.g. Program) from the specified source files. A builder call is a declaration: SCons enters the specified relationship into its internal dependency node graph, and only later makes the decision on whether anything is actually built, since this depends on command-line options, target selection rules, and whether the target(s) are out of date with respect to the sources.
SCons provides a number of builders, and you can also write your own (see Builder Objects). Builders are created dynamically at run-time, often (though not always) by tools which determine whether the external dependencies for the builder are satisfied, and which perform the necessary setup (see Tools). Builders are attached to a construction environment as methods. The available builder methods are registered as key-value pairs in the $BUILDERS attribute of the construction environment, so the available builders can be examined. This example displays them for debugging purposes:
env = Environment()
print("Builders:", list(env['BUILDERS']))
Builder methods take two required arguments: target and source. The target and source arguments can be specified either as positional arguments, in which case target comes first, or as keyword arguments, using target= and source=. Although both arguments are nominally required, if there is a single source and the target can be inferred the target argument can be omitted (see below). Builder methods also take a variety of keyword arguments, described below.
Because long lists of file names can lead to a lot of quoting in a builder call, SCons supplies a Split global function and a same-named environment method that splits a single string into a list, using strings of white-space characters as the delimiter (similar to the Python string split method, but succeeds even if the input isn't a string).
The following are equivalent examples of calling the Program builder method:
env.Program('bar', ['bar.c', 'foo.c'])
env.Program('bar', Split('bar.c foo.c'))
env.Program('bar', env.Split('bar.c foo.c'))
env.Program(source=['bar.c', 'foo.c'], target='bar')
env.Program(target='bar', source=Split('bar.c foo.c'))
env.Program(target='bar', source=env.Split('bar.c foo.c'))
env.Program('bar', source='bar.c foo.c'.split())
Sources and targets can be specified as a scalar or as a list, composed of either strings or nodes (more on nodes below). When specifying path strings, Python follows the POSIX pathname convention: if a string begins with the operating system pathname separator (on Windows both the slash and backslash separator are accepted, and any leading drive specifier is ignored for the determination) it is considered an absolute path, otherwise it is a relative path. If the path string contains no separator characters, it is searched for as a file in the current directory. If it contains separator characters, the search follows down from the starting point, which is the top of the directory tree for an absolute path and the current directory for a relative path. The "current directory" in this context is the directory of the SConscript file currently being processed.
SCons also recognizes a third way to specify path strings: if the string begins with the # character it is top-relative - it works like a relative path but the search follows down from the directory containing the top-level SConstruct rather than from the current directory. The # can optionally be followed by a pathname separator, which is ignored if found in that position. Top-relative paths only work in places where scons will interpret the path (see some examples below). To be used in other contexts the string will need to be converted to a relative or absolute path first.
Examples:
# The comments describing the targets that will be built
# assume these calls are in a SConscript file in the
# a subdirectory named "subdir".
# Builds the program "subdir/foo" from "subdir/foo.c":
env.Program('foo', 'foo.c')
# Builds the program "/tmp/bar" from "subdir/bar.c":
env.Program('/tmp/bar', 'bar.c')
# An initial '#' or '#/' are equivalent; the following
# calls build the programs "foo" and "bar" (in the
# top-level SConstruct directory) from "subdir/foo.c" and
# "subdir/bar.c", respectively:
env.Program('#foo', 'foo.c')
env.Program('#/bar', 'bar.c')
# Builds the program "other/foo" (relative to the top-level
# SConstruct directory) from "subdir/foo.c":
env.Program('#other/foo', 'foo.c')
# This will not work, only SCons interfaces understand '#',
# os.path.exists is pure Python:
if os.path.exists('#inc/foo.h'):
env.Append(CPPPATH='#inc')
When the target shares the same base name as the source and only the suffix varies, and if the builder method has a suffix defined for the target file type, then the target argument may be omitted completely, and scons will deduce the target file name from the source file name. The following examples all build the executable program bar (on POSIX systems) or bar.exe (on Windows systems) from the bar.c source file:
env.Program(target='bar', source='bar.c')
env.Program('bar', source='bar.c')
env.Program(source='bar.c')
env.Program('bar.c')
The optional srcdir keyword argument specifies that all source file strings that are not absolute paths or top-relative paths shall be interpreted relative to the specified srcdir. The following example will build the build/prog (or build/prog.exe on Windows) program from the files src/f1.c and src/f2.c:
env.Program('build/prog', ['f1.c', 'f2.c'], srcdir='src')
The optional parse_flags keyword argument causes behavior similar to the env.MergeFlags method, where the argument value is broken into individual settings and merged into the appropriate construction variables.
env.Program('hello', 'hello.c', parse_flags='-Iinclude -DEBUG -lm')
This example adds 'include' to the $CPPPATH construction variable, 'EBUG' to $CPPDEFINES, and 'm' to $LIBS.
The optional chdir keyword argument specifies that the Builder's action(s) should be executed after changing directory. If the chdir argument is a path string or a directory Node, scons will change to the specified directory. If the chdir is not a string or Node and evaluates true, then scons will change to the target file's directory.
Warning
Python only keeps one current directory location even if there are multiple threads. This means that use of the chdir argument will not work with the SCons -j option, because individual worker threads spawned by SCons interfere with each other when they start changing directory.
# scons will change to the "sub" subdirectory # before executing the "cp" command. env.Command(
target='sub/dir/foo.out',
source='sub/dir/foo.in',
action="cp dir/foo.in dir/foo.out",
chdir='sub', ) # Because chdir is not a string, scons will change to the # target's directory ("sub/dir") before executing the # "cp" command. env.Command('sub/dir/foo.out', 'sub/dir/foo.in', "cp foo.in foo.out", chdir=True)
Note that SCons will not automatically modify its expansion of construction variables like $TARGET and $SOURCE when using the chdir keyword argument--that is, the expanded file names will still be relative to the top-level directory where the SConstruct was found, and consequently incorrect relative to the chdir directory. If you use the chdir keyword argument, you will typically need to supply a different command line using expansions like ${TARGET.file} and ${SOURCE.file} to use just the filename portion of the target and source.
Keyword arguments that are not specifically recognized are treated as construction variable overrides, which replace or add those variables on a limited basis. These overrides will only be in effect when building the target of the builder call, and will not affect other parts of the build. For example, if you want to specify some libraries needed by just one program:
env.Program('hello', 'hello.c', LIBS=['gl', 'glut'])
or generate a shared library with a non-standard suffix:
env.SharedLibrary(
target='word',
source='word.cpp',
SHLIBSUFFIX='.ocx',
LIBSUFFIXES=['.ocx'], )
Note that both the $SHLIBSUFFIX and $LIBSUFFIXES construction variables must be set if you want scons to search automatically for dependencies on the non-standard library names; see the descriptions of these variables for more information.
Although the builder methods defined by scons are, in fact, methods of a construction environment object, many may also be called without an explicit environment:
Program('hello', 'hello.c')
SharedLibrary('word', 'word.cpp')
If called this way, the builder will internally use the Default Environment that consists of the tools and values that scons has determined are appropriate for the local system.
Builder methods that can be called without an explicit environment (indicated in the listing of builders below without a leading env.) may be called from custom Python modules that you import into an SConscript file by adding the following to the Python module:
from SCons.Script import *
A builder may add additional targets beyond those requested if an attached Emitter chooses to do so (see the section called “Builder Objects” for more information. $PROGEMITTER is an example). For example, the GNU linker takes a command-line argument -Map=mapfile, which causes it to produce a linker map file in addition to the executable file actually being linked. If the Program builder's emitter is configured to add this mapfile if the option is set, then two targets will be returned when you only provided for one.
For this reason, builder methods always return a NodeList, a list-like object whose elements are Nodes. Nodes are the internal representation of build targets or sources (see the section called “Node Objects” for more information). The returned NodeList object can be passed to other builder methods as source(s) or to other SCons functions or methods where a path string would normally be accepted.
For example, to add a specific preprocessor define when compiling one specific object file but not the others:
bar_obj_list = env.StaticObject('bar.c', CPPDEFINES='-DBAR')
env.Program("prog", ['foo.c', bar_obj_list, 'main.c'])
Using a Node as in this example makes for a more portable build by avoiding having to specify a platform-specific object suffix when calling the Program builder method.
The NodeList object is also convenient to pass to the Default function, for the same reason of avoiding a platform-specific name:
tgt = env.Program("prog", ["foo.c", "bar.c", "main.c"])
Default(tgt)
Builder calls will automatically "flatten" lists passed as source and target, so they are free to contain elements which are themselves lists, such as bar_obj_list returned by the StaticObject call. If you need to manipulate a list of lists returned by builders directly in Python code, you can either build a new list by hand:
foo = Object('foo.c')
bar = Object('bar.c')
objects = ['begin.o'] + foo + ['middle.o'] + bar + ['end.o']
for obj in objects:
print(str(obj))
Or you can use the Flatten function supplied by SCons to create a list containing just the Nodes, which may be more convenient:
foo = Object('foo.c')
bar = Object('bar.c')
objects = Flatten(['begin.o', foo, 'middle.o', bar, 'end.o'])
for obj in objects:
print(str(obj))
Since builder calls return a list-like object, not an actual Python list, it is not appropriate to use the Python add operator (+ or +=) to append builder results to a Python list. Because the list and the object are different types, Python will not update the original list in place, but will instead create a new NodeList object containing the concatenation of the list elements and the builder results. This will cause problems for any other Python variables in your SCons configuration that still hold on to a reference to the original list. Instead, use the Python list extend method to make sure the list is updated in-place. Example:
object_files = []
# Do NOT use += here:
# object_files += Object('bar.c')
#
# It will not update the object_files list in place.
#
# Instead, use the list extend method:
object_files.extend(Object('bar.c'))
The path name for a Node's file may be used by passing the Node to Python's builtin str function:
bar_obj_list = env.StaticObject('bar.c', CPPDEFINES='-DBAR')
print("The path to bar_obj is:", str(bar_obj_list[0]))
Note that because the Builder call returns a NodeList, you have to access the first element in the list (bar_obj_list[0] in the example) to get at the Node that actually represents the object file.
When trying to handle errors that may occur in a builder method, consider that the corresponding Action is executed at a different time than the SConscript file statement calling the builder. It is not useful to wrap a builder call in a try block, since success in the builder call is not the same as the builder itself succeeding. If necessary, a Builder's Action should be coded to exit with a useful exception message indicating the problem in the SConscript files - programmatically recovering from build errors is rarely useful.
The following builder methods are predefined in the SCons core software distribution. Depending on the setup of a particular construction environment and on the type and software installation status of the underlying system, not all builders may be available in that construction environment. Since the function calling signature is the same for all builders:
Buildername(target, source, [key=val, ...])
it is omitted in this listing for brevity.
CFile(), env.CFile()
# builds foo.c env.CFile(target = 'foo.c', source = 'foo.l') # builds bar.c env.CFile(target = 'bar', source = 'bar.y')
Command(), env.Command()
CompilationDatabase(), env.CompilationDatabase()
CompilationDatabase is a special builder which adds a target to create a JSON formatted compilation database compatible with clang tooling (see the LLVM specification[2]). This database is suitable for consumption by various tools and editors who can use it to obtain build and dependency information which otherwise would be internal to SCons. The builder does not require any source files to be specified, rather it arranges to emit information about all of the C, C++ and assembler source/output pairs identified in the build that are not excluded by the optional filter $COMPILATIONDB_PATH_FILTER. The target is subject to the usual SCons target selection rules.
If called with no arguments, the builder will default to a target name of compile_commands.json.
If called with a single positional argument, scons will "deduce" the target name from that source argument, giving it the same name, and then ignore the source. This is the usual way to call the builder if a non-default target name is wanted.
If called with either the target= or source= keyword arguments, the value of the argument is taken as the target name. If called with both, the target= value is used and source= is ignored. If called with multiple sources, the source list will be ignored, since there is no way to deduce what the intent was; in this case the default target name will be used.
Note
You must load the compilation_db tool prior to specifying any part of your build or some source/output files will not show up in the compilation database.
CXXFile(), env.CXXFile()
# builds foo.cc env.CXXFile(target = 'foo.cc', source = 'foo.ll') # builds bar.cc env.CXXFile(target = 'bar', source = 'bar.yy')
DocbookEpub(), env.DocbookEpub()
env = Environment(tools=['docbook'])
env.DocbookEpub('manual.epub', 'manual.xml')
or simply
env = Environment(tools=['docbook'])
env.DocbookEpub('manual')
DocbookHtml(), env.DocbookHtml()
env = Environment(tools=['docbook'])
env.DocbookHtml('manual.html', 'manual.xml')
or simply
env = Environment(tools=['docbook'])
env.DocbookHtml('manual')
DocbookHtmlChunked(), env.DocbookHtmlChunked()
env = Environment(tools=['docbook'])
env.DocbookHtmlChunked('manual')
where manual.xml is the input file.
If you use the root.filename parameter in your own stylesheets you have to specify the new target name. This ensures that the dependencies get correct, especially for the cleanup via “scons -c”:
env = Environment(tools=['docbook'])
env.DocbookHtmlChunked('mymanual.html', 'manual', xsl='htmlchunk.xsl')
Some basic support for the base.dir parameter is provided. You can add the base_dir keyword to your Builder call, and the given prefix gets prepended to all the created filenames:
env = Environment(tools=['docbook'])
env.DocbookHtmlChunked('manual', xsl='htmlchunk.xsl', base_dir='output/')
Make sure that you don't forget the trailing slash for the base folder, else your files get renamed only!
DocbookHtmlhelp(), env.DocbookHtmlhelp()
env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('manual')
where manual.xml is the input file.
If you use the root.filename parameter in your own stylesheets you have to specify the new target name. This ensures that the dependencies get correct, especially for the cleanup via “scons -c”:
env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('mymanual.html', 'manual', xsl='htmlhelp.xsl')
Some basic support for the base.dir parameter is provided. You can add the base_dir keyword to your Builder call, and the given prefix gets prepended to all the created filenames:
env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('manual', xsl='htmlhelp.xsl', base_dir='output/')
Make sure that you don't forget the trailing slash for the base folder, else your files get renamed only!
DocbookMan(), env.DocbookMan()
env = Environment(tools=['docbook'])
env.DocbookMan('manual')
where manual.xml is the input file. Note, that you can specify a target name, but the actual output names are automatically set from the refname entries in your XML source.
DocbookPdf(), env.DocbookPdf()
env = Environment(tools=['docbook'])
env.DocbookPdf('manual.pdf', 'manual.xml')
or simply
env = Environment(tools=['docbook'])
env.DocbookPdf('manual')
DocbookSlidesHtml(), env.DocbookSlidesHtml()
env = Environment(tools=['docbook'])
env.DocbookSlidesHtml('manual')
If you use the titlefoil.html parameter in your own stylesheets you have to give the new target name. This ensures that the dependencies get correct, especially for the cleanup via “scons -c”:
env = Environment(tools=['docbook'])
env.DocbookSlidesHtml('mymanual.html','manual', xsl='slideshtml.xsl')
Some basic support for the base.dir parameter is provided. You can add the base_dir keyword to your Builder call, and the given prefix gets prepended to all the created filenames:
env = Environment(tools=['docbook'])
env.DocbookSlidesHtml('manual', xsl='slideshtml.xsl', base_dir='output/')
Make sure that you don't forget the trailing slash for the base folder, else your files get renamed only!
DocbookSlidesPdf(), env.DocbookSlidesPdf()
env = Environment(tools=['docbook'])
env.DocbookSlidesPdf('manual.pdf', 'manual.xml')
or simply
env = Environment(tools=['docbook'])
env.DocbookSlidesPdf('manual')
DocbookXInclude(), env.DocbookXInclude()
env = Environment(tools=['docbook'])
env.DocbookXInclude('manual_xincluded.xml', 'manual.xml')
DocbookXslt(), env.DocbookXslt()
env = Environment(tools=['docbook'])
env.DocbookXslt('manual_transformed.xml', 'manual.xml', xsl='transform.xslt')
Note, that this builder requires the xsl parameter to be set.
DVI(), env.DVI()
The suffix .dvi (hard-coded within TeX itself) is automatically added to the target if it is not already present. Examples:
# builds from aaa.tex env.DVI(target = 'aaa.dvi', source = 'aaa.tex') # builds bbb.dvi env.DVI(target = 'bbb', source = 'bbb.ltx') # builds from ccc.latex env.DVI(target = 'ccc.dvi', source = 'ccc.latex')
Gs(), env.Gs()
env = Environment(tools=['gs']) env.Gs(
'cover.jpg',
'scons-scons.pdf',
GSFLAGS='-dNOPAUSE -dBATCH -sDEVICE=jpeg -dFirstPage=1 -dLastPage=1 -q', )
Install(), env.Install()
env.Install(target='/usr/local/bin', source=['foo', 'bar'])
Note that if target paths chosen for the Install builder (and the related InstallAs and InstallVersionedLib builders) are outside the project tree, such as in the example above, they may not be selected for "building" by default, since in the absence of other instructions scons builds targets that are underneath the top directory (the directory that contains the SConstruct file, usually the current directory). Use command line targets or the Default function in this case.
If the --install-sandbox command line option is given, the target directory will be prefixed by the directory path specified. This is useful to test installs without installing to a "live" location in the system.
See also FindInstalledFiles. For more thoughts on installation, see the User Guide (particularly the section on Command-Line Targets and the chapters on Installing Files and on Alias Targets).
InstallAs(), env.InstallAs()
env.InstallAs(target='/usr/local/bin/foo',
source='foo_debug') env.InstallAs(target=['../lib/libfoo.a', '../lib/libbar.a'],
source=['libFOO.a', 'libBAR.a'])
See the note under Install.
InstallVersionedLib(), env.InstallVersionedLib()
env.InstallVersionedLib(target='/usr/local/bin/foo',
source='libxyz.1.5.2.so')
See the note under Install.
Jar(), env.Jar()
If the $JARCHDIR value is set, the jar command will change to the specified directory using the -C option. If $JARCHDIR is not set explicitly, SCons will use the top of any subdirectory tree in which Java .class were built by the Java Builder.
If the contents any of the source files begin with the string Manifest-Version, the file is assumed to be a manifest and is passed to the jar command with the m option set.
env.Jar(target = 'foo.jar', source = 'classes') env.Jar(target = 'bar.jar',
source = ['bar1.java', 'bar2.java'])
Java(), env.Java()
SCons will parse each source .java file to find the classes (including inner classes) defined within that file, and from that figure out the target .class files that will be created. The class files will be placed underneath the specified target directory.
SCons will also search each Java file for the Java package name, which it assumes can be found on a line beginning with the string package in the first column; the resulting .class files will be placed in a directory reflecting the specified package name. For example, the file Foo.java defining a single public Foo class and containing a package name of sub.dir will generate a corresponding sub/dir/Foo.class class file.
Examples:
env.Java(target='classes', source='src') env.Java(target='classes', source=['src1', 'src2']) env.Java(target='classes', source=['File1.java', 'File2.java'])
Java source files can use the native encoding for the underlying OS. Since SCons compiles in simple ASCII mode by default, the compiler will generate warnings about unmappable characters, which may lead to errors as the file is processed further. In this case, the user must specify the LANG environment variable to tell the compiler what encoding is used. For portibility, it's best if the encoding is hard-coded so that the compile will work if it is done on a system with a different encoding.
env = Environment() env['ENV']['LANG'] = 'en_GB.UTF-8'
JavaH(), env.JavaH()
If the construction variable $JAVACLASSDIR is set, either in the environment or in the call to the JavaH builder method itself, then the value of the variable will be stripped from the beginning of any .class file names.
Examples:
# builds java_native.h classes = env.Java(target="classdir", source="src") env.JavaH(target="java_native.h", source=classes) # builds include/package_foo.h and include/package_bar.h env.JavaH(target="include", source=["package/foo.class", "package/bar.class"]) # builds export/foo.h and export/bar.h env.JavaH(
target="export",
source=["classes/foo.class", "classes/bar.class"],
JAVACLASSDIR="classes", )
Note
Java versions starting with 10.0 no longer use the javah command for generating JNI headers/sources, and indeed have removed the command entirely (see Java Enhancement Proposal JEP 313[3]), making this tool harder to use for that purpose. SCons may autodiscover a javah belonging to an older release if there are multiple Java versions on the system, which will lead to incorrect results. To use with a newer Java, override the default values of $JAVAH (to contain the path to the javac) and $JAVAHFLAGS (to contain at least a -h flag) and note that generating headers with javac requires supplying source .java files only, not .class files.
Library(), env.Library()
LoadableModule(), env.LoadableModule()
M4(), env.M4()
env.M4(target = 'foo.c', source = 'foo.c.m4')
Moc(), env.Moc()
env.Moc('foo.h') # generates moc_foo.cc
env.Moc('foo.cpp') # generates foo.moc
MOFiles(), env.MOFiles()
Example 1. Create pl.mo and en.mo by compiling pl.po and en.po:
# ...
env.MOFiles(['pl', 'en'])
Example 2. Compile files for languages defined in LINGUAS file:
# ...
env.MOFiles(LINGUAS_FILE = 1)
Example 3. Create pl.mo and en.mo by compiling pl.po and en.po plus files for languages defined in LINGUAS file:
# ...
env.MOFiles(['pl', 'en'], LINGUAS_FILE = 1)
Example 4. Compile files for languages defined in LINGUAS file (another version):
# ...
env['LINGUAS_FILE'] = 1
env.MOFiles()
MSVSProject(), env.MSVSProject()
Builds a C++ project file based on the version of Visual Studio (or to be more precise, of MSBuild) that is configured: either the latest installed version, or the version specified by $MSVC_VERSION in the current construction environment. For Visual Studio 6.0 a .dsp file is generated. For Visual Studio versions 2002-2008, a .vcproj file is generated. For Visual Studio 2010 and later a .vcxproj file is generated. Note there are multiple versioning schemes involved in the Microsoft compilation environment - see the description of $MSVC_VERSION for equivalences. SCons does not know how to construct project files for other languages (such as .csproj for C#, .vbproj for Visual Basic or .pyproject for Python)).
For the .vcxproj file, the underlying format is the MSBuild XML Schema, and the details conform to: https://learn.microsoft.com/en-us/cpp/build/reference/vcxproj-file-structure[4]. The generated solution file enables Visual Studio to understand the project structure, and allows building it using MSBuild to call back to SCons. The project file encodes a toolset version that has been selected by SCons as described above. Since recent Visual Studio versions support multiple concurrent toolsets, use $MSVC_VERSION to select the desired one if it does not match the SCons default. The project file also includes entries which describe how to call SCons to build the project from within Visual Studio (or from an MSBuild command line). In some situations SCons may generate this incorrectly - notably when using the scons-local distribution, which is not installed in a way that that matches the default invocation line. If so, the $SCONS_HOME construction variable can be used to describe the right way to locate the SCons code so that it can be imported.
By default, a matching solution file for the project is also generated. This behavior may be disabled by specifying auto_build_solution=0 to the MSVSProject builder. The solution file can also be independently generated by calling the MSVSSolution builder, such as in the case where a solution should describe multiple projects. See the MSVSSolution description for further information.
The MSVSProject builder accepts several keyword arguments describing lists of filenames to be placed into the project file. Currently, srcs, incs, localincs, resources, and misc are recognized. The names are intended to be self-explanatory, but note that the filenames need to be specified as strings, not as SCons File Nodes (for example if you generate files for inclusion by using the Glob function, the results should be converted to a list of strings before passing them to MSVSProject). This is because Visual Studio and MSBuild know nothing about SCons Node types. Each of the filename lists are individually optional, but at least one list must be specified for the resulting project file to be non-empty.
In addition to the above lists of values, the following values may be specified as keyword arguments:
target
variant
cmdargs
cppdefines
cppflags
cpppaths
buildtarget
runfile
Note
SCons and Microsoft Visual Studio understand projects in different ways, and the mapping is sometimes imperfect:
Because SCons always executes its build commands from the directory in which the SConstruct file is located, if you generate a project file in a different directory than the directory of the SConstruct file, users will not be able to double-click on the file name in compilation error messages displayed in the Visual Studio console output window. This can be remedied by adding the Visual C/C++ /FC compiler option to the $CCFLAGS variable so that the compiler will print the full path name of any files that cause compilation errors.
If the project file is only used to teach the Visual Studio project browser about the file layout there should be no issues, However, Visual Studio should not be used to make changes to the project structure, build options, etc. as these will (a) not feed back to the SCons description of the project and (b) be lost if SCons regenerates the project file. The SConscript files should remain the definitive description of the build.
If the project file is used to drive MSBuild (such as selecting "build" from the Visual Studio interface) you lose the direct control of target selection and command-line options you would have if launching the build directly from SCons, because these will be hardcoded in the project file to the values specified in the MSVSProject call. You can regain some of this control by defining multiple variants, using multiple MSVSProject calls to arrange different build targets, arguments, defines, flags and paths for different variants.
If the build is divided into a solution with multiple MSBuild projects the mapping is further strained. In this case, it is important not to set Visual Studio to do parallel builds, as it will then launch the separate project builds in parallel, and SCons does not work well if called that way. Instead you can set up the SCons build for parallel building - see the SetOption function for how to do this with num_jobs.
barsrcs = ['bar.cpp']
barincs = ['bar.h']
barlocalincs = ['StdAfx.h']
barresources = ['bar.rc', 'resource.h']
barmisc = ['bar_readme.txt']
dll = env.SharedLibrary(target='bar.dll', source=barsrcs)
buildtarget = [s for s in dll if str(s).endswith('dll')]
env.MSVSProject(
target='Bar' + env['MSVSPROJECTSUFFIX'],
srcs=barsrcs,
incs=barincs,
localincs=barlocalincs,
resources=barresources,
misc=barmisc,
buildtarget=buildtarget,
variant='Release',
)
DebugSettings
Changed in version 2.4: Added the optional DebugSettings parameter.
Currently, only Visual Studio v9.0 and Visual Studio version v11 are implemented, for other versions no file is generated. To generate the user file, you just need to add a DebugSettings dictionary to the environment with the right parameters for your MSVS version. If the dictionary is empty, or does not contain any good value, no file will be generated.
Following is a more contrived example, involving the setup of a project for variants and DebugSettings:
# Assuming you store your defaults in a file
vars = Variables('variables.py')
msvcver = vars.args.get('vc', '9')
# Check command args to force one Microsoft Visual Studio version
if msvcver == '9' or msvcver == '11':
env = Environment(MSVC_VERSION=msvcver + '.0', MSVC_BATCH=False)
else:
env = Environment()
AddOption(
'--userfile',
action='store_true',
dest='userfile',
default=False,
help="Create Visual C++ project file",
)
#
# 1. Configure your Debug Setting dictionary with options you want in the list
# of allowed options, for instance if you want to create a user file to launch
# a specific application for testing your dll with Microsoft Visual Studio 2008 (v9):
#
V9DebugSettings = {
'Command': 'c:\\myapp\\using\\thisdll.exe',
'WorkingDirectory': 'c:\\myapp\\using\\',
'CommandArguments': '-p password',
# 'Attach':'false',
# 'DebuggerType':'3',
# 'Remote':'1',
# 'RemoteMachine': None,
# 'RemoteCommand': None,
# 'HttpUrl': None,
# 'PDBPath': None,
# 'SQLDebugging': None,
# 'Environment': '',
# 'EnvironmentMerge':'true',
# 'DebuggerFlavor': None,
# 'MPIRunCommand': None,
# 'MPIRunArguments': None,
# 'MPIRunWorkingDirectory': None,
# 'ApplicationCommand': None,
# 'ApplicationArguments': None,
# 'ShimCommand': None,
# 'MPIAcceptMode': None,
# 'MPIAcceptFilter': None,
}
#
# 2. Because there are a lot of different options depending on the Microsoft
# Visual Studio version, if you use more than one version you have to
# define a dictionary per version, for instance if you want to create a user
# file to launch a specific application for testing your dll with Microsoft
# Visual Studio 2012 (v11):
#
V10DebugSettings = {
'LocalDebuggerCommand': 'c:\\myapp\\using\\thisdll.exe',
'LocalDebuggerWorkingDirectory': 'c:\\myapp\\using\\',
'LocalDebuggerCommandArguments': '-p password',
# 'LocalDebuggerEnvironment': None,
# 'DebuggerFlavor': 'WindowsLocalDebugger',
# 'LocalDebuggerAttach': None,
# 'LocalDebuggerDebuggerType': None,
# 'LocalDebuggerMergeEnvironment': None,
# 'LocalDebuggerSQLDebugging': None,
# 'RemoteDebuggerCommand': None,
# 'RemoteDebuggerCommandArguments': None,
# 'RemoteDebuggerWorkingDirectory': None,
# 'RemoteDebuggerServerName': None,
# 'RemoteDebuggerConnection': None,
# 'RemoteDebuggerDebuggerType': None,
# 'RemoteDebuggerAttach': None,
# 'RemoteDebuggerSQLDebugging': None,
# 'DeploymentDirectory': None,
# 'AdditionalFiles': None,
# 'RemoteDebuggerDeployDebugCppRuntime': None,
# 'WebBrowserDebuggerHttpUrl': None,
# 'WebBrowserDebuggerDebuggerType': None,
# 'WebServiceDebuggerHttpUrl': None,
# 'WebServiceDebuggerDebuggerType': None,
# 'WebServiceDebuggerSQLDebugging': None,
}
#
# 3. Select the dictionary you want depending on the version of visual Studio
# Files you want to generate.
#
if not env.GetOption('userfile'):
dbgSettings = None
elif env.get('MSVC_VERSION', None) == '9.0':
dbgSettings = V9DebugSettings
elif env.get('MSVC_VERSION', None) == '11.0':
dbgSettings = V10DebugSettings
else:
dbgSettings = None
#
# 4. Add the dictionary to the DebugSettings keyword.
#
barsrcs = ['bar.cpp', 'dllmain.cpp', 'stdafx.cpp']
barincs = ['targetver.h']
barlocalincs = ['StdAfx.h']
barresources = ['bar.rc', 'resource.h']
barmisc = ['ReadMe.txt']
dll = env.SharedLibrary(target='bar.dll', source=barsrcs)
env.MSVSProject(
target='Bar' + env['MSVSPROJECTSUFFIX'],
srcs=barsrcs,
incs=barincs,
localincs=barlocalincs,
resources=barresources,
misc=barmisc,
buildtarget=[dll[0]] * 2,
variant=('Debug|Win32', 'Release|Win32'),
cmdargs=f'vc={msvcver}',
DebugSettings=(dbgSettings, {}),
)
MSVSSolution(), env.MSVSSolution()
Builds a Visual Studio solution file based on the version of Visual Studio that is configured: either the latest installed version, or the version specified by $MSVC_VERSION in the construction environment. For Visual Studio 6, a .dsw file is generated. For Visual Studio .NET 2002 and later, it will generate a .sln file. Note there are multiple versioning schemes involved in the Microsoft compilation environment - see the description of $MSVC_VERSION for equivalences.
The solution file is a container for one or more projects, and follows the format described at https://learn.microsoft.com/en-us/visualstudio/extensibility/internals/solution-dot-sln-file[5].
The following values must be specified:
target
variant
projects
Example Usage:
env.MSVSSolution(
target="Bar" + env["MSVSSOLUTIONSUFFIX"],
projects=["bar" + env["MSVSPROJECTSUFFIX"]],
variant="Release", )
Ninja(), env.Ninja()
Note
This is an experimental feature. To enable it you must use one of the following methods
# On the command line
--experimental=ninja
# Or in your SConstruct
SetOption('experimental', 'ninja')
This functionality is subject to change and/or removal without deprecation cycle.
To use this tool you need to install the Python ninja package, as the tool by default depends on being able to do an import of the package This can be done via:
python -m pip install ninja
If called with a single positional argument, scons will "deduce" the target name from that source argument, giving it the same name, and then ignore the source. This is the usual way to call the builder if a non-default target name is wanted.
If called with either the target= or source= keyword arguments, the value of the argument is taken as the target name. If called with both, the target= value is used and source= is ignored. If called with multiple sources, the source list will be ignored, since there is no way to deduce what the intent was; in this case the default target name will be used.
Available since scons 4.2.
Object(), env.Object()
Package(), env.Package()
env = Environment(tools=['default', 'packaging'])
SCons can build packages in a number of well known packaging formats. The target package type may be selected with the the $PACKAGETYPE construction variable or the --package-type command line option. The package type may be a list, in which case SCons will attempt to build packages for each type in the list. Example:
env.Package(PACKAGETYPE=['src_zip', 'src_targz'], ...other args...)
The currently supported packagers are:
| msi | Microsoft Installer package |
| rpm | RPM Package Manger package |
| ipkg | Itsy Package Management package |
| tarbz2 | bzip2-compressed tar file |
| targz | gzip-compressed tar file |
| tarxz | xz-compressed tar file |
| zip | zip file |
| src_tarbz2 | bzip2-compressed tar file suitable as source to another packager |
| src_targz | gzip-compressed tar file suitable as source to another packager |
| src_tarxz | xz-compressed tar file suitable as source to another packager |
| src_zip | zip file suitable as source to another packager |
The file list to include in the package may be specified with the source keyword argument. If omitted, the FindInstalledFiles function is called behind the scenes to select all files that have an Install, InstallAs or InstallVersionedLib Builder attached. If the target keyword argument is omitted, the target name(s) will be deduced from the package type(s).
The metadata comes partly from attributes of the files to be packaged, and partly from packaging tags. Tags can be passed as keyword arguments to the Package builder call, and may also be attached to files (or more accurately, Nodes representing files) with the Tag function. Some package-level tags are mandatory, and will lead to errors if omitted. The mandatory tags vary depending on the package type.
While packaging, the builder uses a temporary location named by the value of the $PACKAGEROOT variable - the package sources are copied there before packaging.
Packaging example:
env = Environment(tools=["default", "packaging"])
env.Install("/bin/", "my_program")
env.Package(
NAME="foo",
VERSION="1.2.3",
PACKAGEVERSION=0,
PACKAGETYPE="rpm",
LICENSE="gpl",
SUMMARY="balalalalal",
DESCRIPTION="this should be really really long",
X_RPM_GROUP="Application/fu",
SOURCE_URL="https://foo.org/foo-1.2.3.tar.gz",
)
In this example, the target /bin/my_program created by the Install call would not be built by default since it is not under the project top directory. However, since no source is specified to the Package builder, it is selected for packaging by the default sources rule. Since packaging is done using $PACKAGEROOT, no write is actually done to the system's /bin directory, and the target will be selected since after rebasing to underneath $PACKAGEROOT it is now under the top directory of the project.
PCH(), env.PCH()
env['PCH'] = env.PCH('StdAfx.cpp')[0]
PDF(), env.PDF()
# builds from aaa.tex env.PDF(target = 'aaa.pdf', source = 'aaa.tex') # builds bbb.pdf from bbb.dvi env.PDF(target = 'bbb', source = 'bbb.dvi')
POInit(), env.POInit()
Target nodes defined through POInit are not built by default (they're Ignored from '.' node) but are added to special Alias ('po-create' by default). The alias name may be changed through the $POCREATE_ALIAS construction variable. All PO files defined through POInit may be easily initialized by scons po-create.
Example 1. Initialize en.po and pl.po from messages.pot:
# ...
env.POInit(['en', 'pl']) # messages.pot --> [en.po, pl.po]
Example 2. Initialize en.po and pl.po from foo.pot:
# ...
env.POInit(['en', 'pl'], ['foo']) # foo.pot --> [en.po, pl.po]
Example 3. Initialize en.po and pl.po from foo.pot but using $POTDOMAIN construction variable:
# ...
env.POInit(['en', 'pl'], POTDOMAIN='foo') # foo.pot --> [en.po, pl.po]
Example 4. Initialize PO files for languages defined in LINGUAS file. The files will be initialized from template messages.pot:
# ...
env.POInit(LINGUAS_FILE = 1) # needs 'LINGUAS' file
Example 5. Initialize en.po and pl.pl PO files plus files for languages defined in LINGUAS file. The files will be initialized from template messages.pot:
# ...
env.POInit(['en', 'pl'], LINGUAS_FILE = 1)
Example 6. You may preconfigure your environment first, and then initialize PO files:
# ...
env['POAUTOINIT'] = 1
env['LINGUAS_FILE'] = 1
env['POTDOMAIN'] = 'foo'
env.POInit()
which has same efect as:
# ...
env.POInit(POAUTOINIT = 1, LINGUAS_FILE = 1, POTDOMAIN = 'foo')
PostScript(), env.PostScript()
# builds from aaa.tex env.PostScript(target = 'aaa.ps', source = 'aaa.tex') # builds bbb.ps from bbb.dvi env.PostScript(target = 'bbb', source = 'bbb.dvi')
POTUpdate(), env.POTUpdate()
Note
You may see xgettext(1) being invoked by the xgettext tool even if there is no real change in internationalized messages (so the POT file is not being updated). This happens every time a source file has changed. In such case we invoke xgettext(1) and compare its output with the content of POT file to decide whether the file should be updated or not.
Example 1. Let's create po/ directory and place following SConstruct script there:
# SConstruct in 'po/' subdir
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(['foo'], ['../a.cpp', '../b.cpp'])
env.POTUpdate(['bar'], ['../c.cpp', '../d.cpp'])
Then invoke scons few times:
user@host:$ scons # Does not create foo.pot nor bar.pot
user@host:$ scons foo.pot # Updates or creates foo.pot
user@host:$ scons pot-update # Updates or creates foo.pot and bar.pot
user@host:$ scons -c # Does not clean foo.pot nor bar.pot.
the results shall be as the comments above say.
Example 2. The POTUpdate builder may be used with no target specified, in which case default target messages.pot will be used. The default target may also be overridden by setting $POTDOMAIN construction variable or providing it as an override to POTUpdate builder:
# SConstruct script
env = Environment( tools = ['default', 'xgettext'] )
env['POTDOMAIN'] = "foo"
env.POTUpdate(source = ["a.cpp", "b.cpp"]) # Creates foo.pot ...
env.POTUpdate(POTDOMAIN = "bar", source = ["c.cpp", "d.cpp"]) # and bar.pot
Example 3. The sources may be specified within separate file, for example POTFILES.in:
# POTFILES.in in 'po/' subdirectory
../a.cpp
../b.cpp
# end of file
The name of the file (POTFILES.in) containing the list of sources is provided via $XGETTEXTFROM:
# SConstruct file in 'po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in')
Example 4. You may use $XGETTEXTPATH to define source search path. Assume, for example, that you have files a.cpp, b.cpp, po/SConstruct, po/POTFILES.in. Then your POT-related files could look as below:
# POTFILES.in in 'po/' subdirectory
a.cpp
b.cpp
# end of file
# SConstruct file in 'po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH='../')
Example 5. Multiple search directories may be defined within a list, i.e. XGETTEXTPATH = ['dir1', 'dir2', ...]. The order in the list determines the search order of source files. The path to the first file found is used.
Let's create 0/1/po/SConstruct script:
# SConstruct file in '0/1/po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH=['../', '../../'])
and 0/1/po/POTFILES.in:
# POTFILES.in in '0/1/po/' subdirectory
a.cpp
# end of file
Write two *.cpp files, the first one is 0/a.cpp:
/* 0/a.cpp */
gettext("Hello from ../../a.cpp")
and the second is 0/1/a.cpp:
/* 0/1/a.cpp */
gettext("Hello from ../a.cpp")
then run scons. You'll obtain 0/1/po/messages.pot with the message "Hello from ../a.cpp". When you reverse order in $XGETTEXTFOM, i.e. when you write SConscript as
# SConstruct file in '0/1/po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH=['../../', '../'])
then the messages.pot will contain msgid "Hello from ../../a.cpp" line and not msgid "Hello from ../a.cpp".
POUpdate(), env.POUpdate()
Target nodes defined through POUpdate are not built by default (they're Ignored from '.' node). Instead, they are added automatically to special Alias ('po-update' by default). The alias name may be changed through the $POUPDATE_ALIAS construction variable. You can easily update PO files in your project by scons po-update.
Example 1. Update en.po and pl.po from messages.pot template (see also $POTDOMAIN), assuming that the later one exists or there is rule to build it (see POTUpdate):
# ...
env.POUpdate(['en','pl']) # messages.pot --> [en.po, pl.po]
Example 2. Update en.po and pl.po from foo.pot template:
# ...
env.POUpdate(['en', 'pl'], ['foo']) # foo.pot --> [en.po, pl.pl]
Example 3. Update en.po and pl.po from foo.pot (another version):
# ...
env.POUpdate(['en', 'pl'], POTDOMAIN='foo') # foo.pot -- > [en.po, pl.pl]
Example 4. Update files for languages defined in LINGUAS file. The files are updated from messages.pot template:
# ...
env.POUpdate(LINGUAS_FILE = 1) # needs 'LINGUAS' file
Example 5. Same as above, but update from foo.pot template:
# ...
env.POUpdate(LINGUAS_FILE = 1, source = ['foo'])
Example 6. Update en.po and pl.po plus files for languages defined in LINGUAS file. The files are updated from messages.pot template:
# produce 'en.po', 'pl.po' + files defined in 'LINGUAS':
env.POUpdate(['en', 'pl' ], LINGUAS_FILE = 1)
Example 7. Use $POAUTOINIT to automatically initialize PO file if it doesn't exist:
# ...
env.POUpdate(LINGUAS_FILE = 1, POAUTOINIT = 1)
Example 8. Update PO files for languages defined in LINGUAS file. The files are updated from foo.pot template. All necessary settings are pre-configured via environment.
# ...
env['POAUTOINIT'] = 1
env['LINGUAS_FILE'] = 1
env['POTDOMAIN'] = 'foo'
env.POUpdate()
Program(), env.Program()
env.Program(target='foo', source=['foo.o', 'bar.c', 'baz.f'])
ProgramAllAtOnce(), env.ProgramAllAtOnce()
D sources can be compiled file-by-file as C and C++ source are, and D is integrated into the scons Object and Program builders for this model of build. D codes can though do whole source meta-programming (some of the testing frameworks do this). For this it is imperative that all sources are compiled and linked in a single call to the D compiler. This builder serves that purpose.
env.ProgramAllAtOnce('executable', ['mod_a.d, mod_b.d', 'mod_c.d'])
This command will compile the modules mod_a, mod_b, and mod_c in a single compilation process without first creating object files for the modules. Some of the D compilers will create executable.o others will not.
RES(), env.RES()
env.RES('resource.rc')
RMIC(), env.RMIC()
If the construction variable $JAVACLASSDIR is set, either in the environment or in the call to the RMIC builder method itself, then the value of the variable will be stripped from the beginning of any .class file names.
classes = env.Java(target='classdir', source='src') env.RMIC(target='outdir1', source=classes) env.RMIC(
target='outdir2',
source=['package/foo.class', 'package/bar.class'], ) env.RMIC(
target='outdir3',
source=['classes/foo.class', 'classes/bar.class'],
JAVACLASSDIR='classes', )
RPCGenClient(), env.RPCGenClient()
# Builds src/rpcif_clnt.c
env.RPCGenClient('src/rpcif.x')
RPCGenHeader(), env.RPCGenHeader()
# Builds src/rpcif.h
env.RPCGenHeader('src/rpcif.x')
RPCGenService(), env.RPCGenService()
# Builds src/rpcif_svc.c
env.RPCGenClient('src/rpcif.x')
RPCGenXDR(), env.RPCGenXDR()
# Builds src/rpcif_xdr.c
env.RPCGenClient('src/rpcif.x')
SharedLibrary(), env.SharedLibrary()
env.SharedLibrary(target='bar', source=['bar.c', 'foo.o'])
On Windows systems, the SharedLibrary builder method will always build an import library (.lib) in addition to the shared library (.dll), adding a .lib library with the same basename if there is not already a .lib file explicitly listed in the targets.
On Cygwin systems, the SharedLibrary builder method will always build an import library (.dll.a) in addition to the shared library (.dll), adding a .dll.a library with the same basename if there is not already a .dll.a file explicitly listed in the targets.
Any object files listed in the source must have been built for a shared library (that is, using the SharedObject builder method). scons will raise an error if there is any mismatch.
On some platforms, there is a distinction between a shared library (loaded automatically by the system to resolve external references) and a loadable module (explicitly loaded by user action). For maximum portability, use the LoadableModule builder for the latter.
When the $SHLIBVERSION construction variable is defined, a versioned shared library is created. This modifies $SHLINKFLAGS as required, adds the version number to the library name, and creates any symbolic links that are needed.
env.SharedLibrary(target='bar', source=['bar.c', 'foo.o'], SHLIBVERSION='1.5.2')
On a POSIX system, versions with a single token create exactly one symlink: libbar.so.6 would have symlink libbar.so only. On a POSIX system, versions with two or more tokens create exactly two symlinks: libbar.so.2.3.1 would have symlinks libbar.so and libbar.so.2; on a Darwin (OSX) system the library would be libbar.2.3.1.dylib and the link would be libbar.dylib.
On Windows systems, specifying register=1 will cause the .dll to be registered after it is built. The command that is run is determined by the $REGSVR construction variable (regsvr32 by default), and the flags passed are determined by $REGSVRFLAGS. By default, $REGSVRFLAGS includes the /s option, to prevent dialogs from popping up and requiring user attention when it is run. If you change $REGSVRFLAGS, be sure to include the /s option. For example,
env.SharedLibrary(target='bar', source=['bar.cxx', 'foo.obj'], register=1)
will register bar.dll as a COM object when it is done linking it.
SharedObject(), env.SharedObject()
env.SharedObject(target='ddd', source='ddd.c') env.SharedObject(target='eee.o', source='eee.cpp') env.SharedObject(target='fff.obj', source='fff.for')
Note that the source files will be scanned according to the suffix mappings in the SourceFileScanner object. See the manpage section "Scanner Objects" for more information.
StaticLibrary(), env.StaticLibrary()
env.StaticLibrary(target='bar', source=['bar.c', 'foo.o'])
Any object files listed in the source must have been built for a static library (that is, using the StaticObject builder method). scons will raise an error if there is any mismatch.
StaticObject(), env.StaticObject()
.asm assembly language file
.ASM assembly language file
.c C file
.C Windows: C file
POSIX: C++ file
.cc C++ file
.cpp C++ file
.cxx C++ file
.cxx C++ file
.c++ C++ file
.C++ C++ file
.d D file
.f Fortran file
.F Windows: Fortran file
POSIX: Fortran file + C pre-processor
.for Fortran file
.FOR Fortran file
.fpp Fortran file + C pre-processor
.FPP Fortran file + C pre-processor
.m Object C file
.mm Object C++ file
.s assembly language file
.S Windows: assembly language file
ARM: CodeSourcery Sourcery Lite
.sx assembly language file + C pre-processor
POSIX: assembly language file + C pre-processor
.spp assembly language file + C pre-processor
.SPP assembly language file + C pre-processor
The target object file prefix, specified by the $OBJPREFIX construction variable (nothing by default), and suffix, specified by the $OBJSUFFIX construction variable (.obj on Windows systems, .o on POSIX systems), are automatically added to the target if not already present. Examples:
env.StaticObject(target='aaa', source='aaa.c') env.StaticObject(target='bbb.o', source='bbb.c++') env.StaticObject(target='ccc.obj', source='ccc.f')
Note that the source files will be scanned according to the suffix mappings in the SourceFileScanner object. See the manpage section "Scanner Objects" for more information.
Substfile(), env.Substfile()
By default the target file encoding is "utf-8" and can be changed by $FILE_ENCODING Examples:
If a single source file name is specified and has a .in suffix, the suffix is stripped and the remainder of the name is used as the default target name.
The prefix and suffix specified by the $SUBSTFILEPREFIX and $SUBSTFILESUFFIX construction variables (an empty string by default in both cases) are automatically added to the target if they are not already present.
If a construction variable named $SUBST_DICT is present, it may be either a Python dictionary or a sequence of (key, value) tuples. If it is a dictionary it is converted into a list of tuples with unspecified order, so if one key is a prefix of another key or if one substitution could be further expanded by another subsitition, it is unpredictable whether the expansion will occur.
Any occurrences of a key in the source are replaced by the corresponding value, which may be a Python callable function or a string. If the value is a callable, it is called with no arguments to get a string. Strings are subst-expanded and the result replaces the key.
env = Environment(tools=['default'])
env['prefix'] = '/usr/bin'
script_dict = {'@prefix@': '/bin', '@exec_prefix@': '$prefix'}
env.Substfile('script.in', SUBST_DICT=script_dict)
conf_dict = {'%VERSION%': '1.2.3', '%BASE%': 'MyProg'}
env.Substfile('config.h.in', conf_dict, SUBST_DICT=conf_dict)
# UNPREDICTABLE - one key is a prefix of another
bad_foo = {'$foo': '$foo', '$foobar': '$foobar'}
env.Substfile('foo.in', SUBST_DICT=bad_foo)
# PREDICTABLE - keys are applied longest first
good_foo = [('$foobar', '$foobar'), ('$foo', '$foo')]
env.Substfile('foo.in', SUBST_DICT=good_foo)
# UNPREDICTABLE - one substitution could be futher expanded
bad_bar = {'@bar@': '@soap@', '@soap@': 'lye'}
env.Substfile('bar.in', SUBST_DICT=bad_bar)
# PREDICTABLE - substitutions are expanded in order
good_bar = (('@bar@', '@soap@'), ('@soap@', 'lye'))
env.Substfile('bar.in', SUBST_DICT=good_bar)
# the SUBST_DICT may be in common (and not an override)
substutions = {}
subst = Environment(tools=['textfile'], SUBST_DICT=substitutions)
substitutions['@foo@'] = 'foo'
subst['SUBST_DICT']['@bar@'] = 'bar'
subst.Substfile(
'pgm1.c',
[Value('#include "@foo@.h"'), Value('#include "@bar@.h"'), "common.in", "pgm1.in"],
)
subst.Substfile(
'pgm2.c',
[Value('#include "@foo@.h"'), Value('#include "@bar@.h"'), "common.in", "pgm2.in"],
)
Tar(), env.Tar()
env.Tar('src.tar', 'src')
# Create the stuff.tar file.
env.Tar('stuff', ['subdir1', 'subdir2'])
# Also add "another" to the stuff.tar file.
env.Tar('stuff', 'another')
# Set TARFLAGS to create a gzip-filtered archive.
env = Environment(TARFLAGS = '-c -z')
env.Tar('foo.tar.gz', 'foo')
# Also set the suffix to .tgz.
env = Environment(TARFLAGS = '-c -z',
TARSUFFIX = '.tgz')
env.Tar('foo')
Textfile(), env.Textfile()
The prefix and suffix specified by the $TEXTFILEPREFIX and $TEXTFILESUFFIX construction variables (by default an empty string and .txt, respectively) are automatically added to the target if they are not already present.
By default the target file encoding is "utf-8" and can be changed by $FILE_ENCODING Examples:
# builds/writes foo.txt env.Textfile(target='foo.txt', source=['Goethe', 42, 'Schiller']) # builds/writes bar.txt env.Textfile(target='bar', source=['lalala', 'tanteratei'], LINESEPARATOR='|*') # nested lists are flattened automatically env.Textfile(target='blob', source=['lalala', ['Goethe', 42, 'Schiller'], 'tanteratei']) # files may be used as input by wraping them in File() env.Textfile(
target='concat', # concatenate files with a marker between
source=[File('concat1'), File('concat2')],
LINESEPARATOR='====================\n', )
Results:
foo.txt
Goethe
42
Schiller
bar.txt
lalala|*tanteratei
blob.txt
lalala
Goethe
42
Schiller
tanteratei
Translate(), env.Translate()
Example 1. The simplest way is to specify input files and output languages inline in a SCons script when invoking Translate
# SConscript in 'po/' directory env = Environment( tools = ["default", "gettext"] ) env['POAUTOINIT'] = 1 env.Translate(['en','pl'], ['../a.cpp','../b.cpp'])
Example 2. If you wish, you may also stick to conventional style known from autotools, i.e. using POTFILES.in and LINGUAS files
# LINGUAS en pl #end
# POTFILES.in a.cpp b.cpp # end
# SConscript env = Environment( tools = ["default", "gettext"] ) env['POAUTOINIT'] = 1 env['XGETTEXTPATH'] = ['../'] env.Translate(LINGUAS_FILE = 1, XGETTEXTFROM = 'POTFILES.in')
The last approach is perhaps the recommended one. It allows easily split internationalization/localization onto separate SCons scripts, where a script in source tree is responsible for translations (from sources to PO files) and script(s) under variant directories are responsible for compilation of PO to MO files to and for installation of MO files. The "gluing factor" synchronizing these two scripts is then the content of LINGUAS file. Note, that the updated POT and PO files are usually going to be committed back to the repository, so they must be updated within the source directory (and not in variant directories). Additionaly, the file listing of po/ directory contains LINGUAS file, so the source tree looks familiar to translators, and they may work with the project in their usual way.
Example 3. Let's prepare a development tree as below
project/
+ SConstruct
+ build/
+ src/
+ po/
+ SConscript
+ SConscript.i18n
+ POTFILES.in
+ LINGUAS
with build being variant directory. Write the top-level SConstruct script as follows
# SConstruct
env = Environment( tools = ["default", "gettext"] )
VariantDir('build', 'src', duplicate = 0)
env['POAUTOINIT'] = 1
SConscript('src/po/SConscript.i18n', exports = 'env')
SConscript('build/po/SConscript', exports = 'env')
the src/po/SConscript.i18n as
# src/po/SConscript.i18n
Import('env')
env.Translate(LINGUAS_FILE=1, XGETTEXTFROM='POTFILES.in', XGETTEXTPATH=['../'])
and the src/po/SConscript
# src/po/SConscript
Import('env')
env.MOFiles(LINGUAS_FILE = 1)
Such setup produces POT and PO files under source tree in src/po/ and binary MO files under variant tree in build/po/. This way the POT and PO files are separated from other output files, which must not be committed back to source repositories (e.g. MO files).
Note
In above example, the PO files are not updated, nor created automatically when you issue scons '.' command. The files must be updated (created) by hand via scons po-update and then MO files can be compiled by running scons '.'.
TypeLibrary(), env.TypeLibrary()
env.TypeLibrary(source="foo.idl")
Will create foo.tlb, foo.h, foo_i.c, foo_p.c and foo_data.c files.
Uic(), env.Uic()
env.Uic('foo.ui') # -> ['foo.h', 'uic_foo.cc', 'moc_foo.cc']
env.Uic(
target=Split('include/foo.h gen/uicfoo.cc gen/mocfoo.cc'),
source='foo.ui'
) # -> ['include/foo.h', 'gen/uicfoo.cc', 'gen/mocfoo.cc']
Zip(), env.Zip()
env.Zip('src.zip', 'src')
# Create the stuff.zip file.
env.Zip('stuff', ['subdir1', 'subdir2'])
# Also add "another" to the stuff.tar file.
env.Zip('stuff', 'another')
All targets of builder methods automatically depend on their sources. An explicit dependency can be specified using the env.Depends method of a construction environment (see below).
In addition, scons automatically scans source files for various programming languages, so the dependencies do not need to be specified explicitly. By default, SCons can C source files, C++ source files, Fortran source files with .F (POSIX systems only), .fpp, or .FPP file extensions, and assembly language files with .S (POSIX systems only), .spp, or .SPP files extensions for C preprocessor dependencies. SCons also has default support for scanning D source files, You can also write your own Scanners to add support for additional source file types. These can be added to the default Scanner object used by the Object, StaticObject and SharedObject Builders by adding them to the SourceFileScanner object. See the section called “Scanner Objects” for more information about defining your own Scanner objects and using the SourceFileScanner object.
Methods and Functions To Do Things¶
In addition to Builder methods, scons provides a number of other construction environment methods and global functions to manipulate the build configuration.
Usually, a construction environment method and global function with the same name both exist for convenience. In the following list, the global function is documented in this style:
Function(arguments, [optional arguments])
and the construction environment method looks like:
env.Function(arguments, [optional arguments])
If the function can be called both ways, then both forms are listed.
The global function and same-named construction environment method provide almost identical functionality, with a couple of exceptions. First, many of the construction environment methods affect only that construction environment, while the global function has a global effect. Second, where appropriate, calling the functionality through a construction environment will substitute construction variables into any supplied string arguments, while the global function doesn't have the context of a construction environment to pick variables from, so it cannot perform the substitution. For example:
Default('$FOO')
env = Environment(FOO='foo')
env.Default('$FOO')
In the above example, the call to the global Default function will add a target named $FOO to the list of default targets, while the call to the env.Default construction environment method will expand the value and add a target named foo to the list of default targets. For more on construction variable expansion, see the next section on construction variables.
Global functions may be called from custom Python modules that you import into an SConscript file by adding the following import to the Python module:
from SCons.Script import *
Construction environment methods and global functions provided by scons include:
Action(action, [output, [var, ...]] [key=value, ...]), env.Action(action, [output, [var, ...]] [key=value, ...])
Note that the env.Action form of the invocation will expand construction variables in any argument strings, including the action argument, at the time it is called using the construction variables in the env construction environment through which env.Action was called. The Action global function form delays all variable expansion until the Action object is actually used.
AddMethod(object, function, [name]), env.AddMethod(function, [name])
When the global function AddMethod is called, the object to add the method to must be passed as the first argument; typically this will be Environment, in order to create a method which applies to all construction environments subsequently constructed. When called using the env.AddMethod form, the method is added to the specified construction environment only. Added methods propagate through env.Clone calls.
More examples:
# Function to add must accept an instance argument. # The Python convention is to call this 'self'. def my_method(self, arg):
print("my_method() got", arg) # Use the global function to add a method to the Environment class: AddMethod(Environment, my_method) env = Environment() env.my_method('arg') # Use the optional name argument to set the name of the method: env.AddMethod(my_method, 'other_method_name') env.other_method_name('another arg')
AddOption(arguments)
In addition to the arguments and values supported by the optparse add_option method, AddOption allows setting the nargs keyword value to a string consisting of a question mark ('?') to indicate that the option argument for that option string is optional. If the option string is present on the command line but has no matching option argument, the value of the const keyword argument is produced as the value of the option. If the option string is omitted from the command line, the value of the default keyword argument is produced, as usual; if there is no default keyword argument in the AddOption call, None is produced.
optparse recognizes abbreviations of long option names, as long as they can be unambiguously resolved. For example, if add_option is called to define a --devicename option, it will recognize --device, --dev and so forth as long as there is no other option which could also match to the same abbreviation. Options added via AddOption do not support the automatic recognition of abbreviations. Instead, to allow specific abbreviations, include them as synonyms in the AddOption call itself.
Once a new command-line option has been added with AddOption, the option value may be accessed using GetOption or env.GetOption. SetOption is not currently supported for options added with AddOption.
Help text for an option is a combination of the string supplied in the help keyword argument to AddOption and information collected from the other keyword arguments. Such help is displayed if the -h command line option is used (but not with -H). Help for all local options is displayed under the separate heading Local Options. The options are unsorted - they will appear in the help text in the order in which the AddOption calls occur.
Example:
AddOption(
'--prefix',
dest='prefix',
nargs=1,
type='string',
action='store',
metavar='DIR',
help='installation prefix', ) env = Environment(PREFIX=GetOption('prefix'))
For that example, the following help text would be produced:
Local Options:
--prefix=DIR installation prefix
Help text for local options may be unavailable if the Help function has been called, see the Help documentation for details.
Note
As an artifact of the internal implementation, the behavior of options added by AddOption which take option arguments is undefined if whitespace (rather than an = sign) is used as the separator on the command line. Users should avoid such usage; it is recommended to add a note to this effect to project documentation if the situation is likely to arise. In addition, if the nargs keyword is used to specify more than one following option argument (that is, with a value of 2 or greater), such arguments would necessarily be whitespace separated, triggering the issue. Developers should not use AddOption this way. Future versions of SCons will likely forbid such usage.
AddPostAction(target, action), env.AddPostAction(target, action)
When multiple targets are supplied, the action may be called multiple times, once after each action that generates one or more targets in the list.
AddPreAction(target, action), env.AddPreAction(target, action)
When multiple targets are specified, the action(s) may be called multiple times, once before each action that generates one or more targets in the list.
Note that if any of the targets are built in multiple steps, the action will be invoked just before the "final" action that specifically generates the specified target(s). For example, when building an executable program from a specified source .c file via an intermediate object file:
foo = Program('foo.c')
AddPreAction(foo, 'pre_action')
The specified pre_action would be executed before scons calls the link command that actually generates the executable program binary foo, not before compiling the foo.c file into an object file.
Alias(alias, [targets, [action]]), env.Alias(alias, [targets, [action]])
Examples:
Alias('install')
Alias('install', '/usr/bin')
Alias(['install', 'install-lib'], '/usr/local/lib')
env.Alias('install', ['/usr/local/bin', '/usr/local/lib'])
env.Alias('install', ['/usr/local/man'])
env.Alias('update', ['file1', 'file2'], "update_database $SOURCES")
AllowSubstExceptions([exception, ...])
If AllowSubstExceptions is called multiple times, each call completely overwrites the previous list of allowed exceptions.
Example:
# Requires that all construction variable names exist.
# (You may wish to do this if you want to enforce strictly
# that all construction variables must be defined before use.)
AllowSubstExceptions()
# Also allow a string containing a zero-division expansion
# like '${1 / 0}' to evalute to ''.
AllowSubstExceptions(IndexError, NameError, ZeroDivisionError)
AlwaysBuild(target, ...), env.AlwaysBuild(target, ...)
env.Append(key=val, [...])
The following descriptions apply to both the Append and Prepend methods, as well as their Unique variants, with the differences being the insertion point of the added values and whether duplication is allowed.
val can be almost any type. If env does not have a construction variable named key, then key is simply stored with a value of val. Otherwise, val is combinined with the existing value, possibly converting into an appropriate type which can hold the expanded contents. There are a few special cases to be aware of. Normally, when two strings are combined, the result is a new string containing their concatenation (and you are responsible for supplying any needed separation); however, the contents of $CPPDEFINES will will be postprocessed by adding a prefix and/or suffix to each entry when the command line is produced, so SCons keeps them separate - appending a string will result in a separate string entry, not a combined string. For $CPPDEFINES. as well as $LIBS, and the various *PATH variables, SCons will amend the variable by supplying the compiler-specific syntax (e.g. prepending a -D or /D prefix for $CPPDEFINES), so you should omit this syntax when adding values to these variables. Examples (gcc syntax shown in the expansion of CPPDEFINES):
env = Environment(CXXFLAGS="-std=c11", CPPDEFINES="RELEASE")
print(f"CXXFLAGS = {env['CXXFLAGS']}, CPPDEFINES = {env['CPPDEFINES']}")
# notice including a leading space in CXXFLAGS addition
env.Append(CXXFLAGS=" -O", CPPDEFINES="EXTRA")
print(f"CXXFLAGS = {env['CXXFLAGS']}, CPPDEFINES = {env['CPPDEFINES']}")
print("CPPDEFINES will expand to", env.subst('$_CPPDEFFLAGS'))
$ scons -Q CXXFLAGS = -std=c11, CPPDEFINES = RELEASE CXXFLAGS = -std=c11 -O, CPPDEFINES = deque(['RELEASE', 'EXTRA']) CPPDEFINES will expand to -DRELEASE -DEXTRA scons: `.' is up to date.
Because $CPPDEFINES is intended for command-line specification of C/C++ preprocessor macros, additional syntax is accepted when adding to it. The preprocessor accepts arguments to predefine a macro name by itself (-DFOO for most compilers, /DFOO for Microsoft C++), which gives it an implicit value of 1, or can be given with a replacement value (-DBAR=TEXT). SCons follows these rules when adding to $CPPDEFINES:
Examples:
env = Environment(CPPDEFINES="FOO")
print("CPPDEFINES =", env['CPPDEFINES'])
env.Append(CPPDEFINES="BAR=1")
print("CPPDEFINES =", env['CPPDEFINES'])
env.Append(CPPDEFINES=[("OTHER", 2)])
print("CPPDEFINES =", env['CPPDEFINES'])
env.Append(CPPDEFINES={"EXTRA": "arg"})
print("CPPDEFINES =", env['CPPDEFINES'])
print("CPPDEFINES will expand to", env.subst('$_CPPDEFFLAGS'))
$ scons -Q
CPPDEFINES = FOO
CPPDEFINES = deque(['FOO', 'BAR=1'])
CPPDEFINES = deque(['FOO', 'BAR=1', ('OTHER', 2)])
CPPDEFINES = deque(['FOO', 'BAR=1', ('OTHER', 2), ('EXTRA', 'arg')])
CPPDEFINES will expand to -DFOO -DBAR=1 -DOTHER=2 -DEXTRA=arg
scons: `.' is up to date.
Examples of adding multiple macros:
env = Environment()
env.Append(CPPDEFINES=[("ONE", 1), "TWO", ("THREE", )])
print("CPPDEFINES =", env['CPPDEFINES'])
env.Append(CPPDEFINES={"FOUR": 4, "FIVE": None})
print("CPPDEFINES =", env['CPPDEFINES'])
print("CPPDEFINES will expand to", env.subst('$_CPPDEFFLAGS'))
$ scons -Q
CPPDEFINES = [('ONE', 1), 'TWO', ('THREE',)]
CPPDEFINES = deque([('ONE', 1), 'TWO', ('THREE',), ('FOUR', 4), ('FIVE', None)])
CPPDEFINES will expand to -DONE=1 -DTWO -DTHREE -DFOUR=4 -DFIVE
scons: `.' is up to date.
Changed in version 4.5: clarifined the use of tuples vs. other types, handling is now consistent across the four functions.
env = Environment()
env.Append(CPPDEFINES=("MACRO1", "MACRO2"))
print("CPPDEFINES =", env['CPPDEFINES'])
env.Append(CPPDEFINES=[("MACRO3", "MACRO4")])
print("CPPDEFINES =", env['CPPDEFINES'])
print("CPPDEFINES will expand to", env.subst('$_CPPDEFFLAGS'))
$ scons -Q
CPPDEFINES = ('MACRO1', 'MACRO2')
CPPDEFINES = deque(['MACRO1', 'MACRO2', ('MACRO3', 'MACRO4')])
CPPDEFINES will expand to -DMACRO1 -DMACRO2 -DMACRO3=MACRO4
scons: `.' is up to date.
See $CPPDEFINES for more details.
Appending a string val to a dictonary-typed construction variable enters val as the key in the dictionary, and None as its value. Using a tuple type to supply a key, value only works for the special case of $CPPDEFINES described above.
Although most combinations of types work without needing to know the details, some combinations do not make sense and Python raises an exception.
When using env.Append to modify construction variables which are path specifications (conventionally, the names of such end in PATH), it is recommended to add the values as a list of strings, even if you are only adding a single string. The same goes for adding library names to $LIBS.
env.Append(CPPPATH=["#/include"])
See also env.AppendUnique, env.Prepend and env.PrependUnique.
env.AppendENVPath(name, newpath, [envname, sep, delete_existing=False])
Example:
print('before:', env['ENV']['INCLUDE'])
include_path = '/foo/bar:/foo'
env.AppendENVPath('INCLUDE', include_path)
print('after:', env['ENV']['INCLUDE'])
Yields:
before: /foo:/biz after: /biz:/foo/bar:/foo
See also env.PrependENVPath.
env.AppendUnique(key=val, [...], [delete_existing=False])
Example:
env.AppendUnique(CCFLAGS='-g', FOO=['foo.yyy'])
See also env.Append, env.Prepend and env.PrependUnique.
Builder(action, [arguments]), env.Builder(action, [arguments])
Note that the env.Builder() form of the invocation will expand construction variables in any arguments strings, including the action argument, at the time it is called using the construction variables in the env construction environment through which env.Builder was called. The Builder form delays all variable expansion until after the Builder object is actually called.
CacheDir(cache_dir, custom_class=None), env.CacheDir(cache_dir, custom_class=None)
When specifying a custom_class which should be a class type which is a subclass of SCons.CacheDir.CacheDir, SCons will internally invoke this class to use for performing caching operations. This argument is optional and if left to default None, will use the default SCons.CacheDir.CacheDir class.
Calling the environment method env.CacheDir limits the effect to targets built through the specified construction environment. Calling the global function CacheDir sets a global default that will be used by all targets built through construction environments that do not set up environment-specific caching by calling env.CacheDir.
When derived-file caching is being used and scons finds a derived file that needs to be rebuilt, it will first look in the cache to see if a file with matching build signature exists (indicating the input file(s) and build action(s) were identical to those for the current target), and if so, will retrieve the file from the cache. scons will report Retrieved `file' from cache instead of the normal build message. If the derived file is not present in the cache, scons will build it and then place a copy of the built file in the cache, identified by its build signature, for future use.
The Retrieved `file' from cache messages are useful for human consumption, but less so when comparing log files between scons runs which will show differences that are noisy and not actually significant. To disable, use the --cache-show option. With this option, scons will print the action that would have been used to build the file without considering cache retrieval.
Derived-file caching may be disabled for any invocation of scons by giving the --cache-disable command line option. Cache updating may be disabled, leaving cache fetching enabled, by giving the --cache-readonly.
If the --cache-force option is used, scons will place a copy of all derived files in the cache, even if they already existed and were not built by this invocation. This is useful to populate a cache the first time a cache_dir is used for a build, or to bring a cache up to date after a build with cache updating disabled (--cache-disable or --cache-readonly) has been done.
The NoCache method can be used to disable caching of specific files. This can be useful if inputs and/or outputs of some tool are impossible to predict or prohibitively large.
Note that (at this time) SCons provides no facilities for managing the derived-file cache. It is up to the developer to arrange for cache pruning, expiry, etc. if needed.
Clean(targets, files_or_dirs), env.Clean(targets, files_or_dirs)
Multiple files or directories should be specified either as separate arguments to the Clean method, or as a list. Clean will also accept the return value of any of the construction environment Builder methods. Examples:
The related NoClean function overrides calling Clean for the same target, and any targets passed to both functions will not be removed by the -c option.
Examples:
Clean('foo', ['bar', 'baz'])
Clean('dist', env.Program('hello', 'hello.c'))
Clean(['foo', 'bar'], 'something_else_to_clean')
In this example, installing the project creates a subdirectory for the documentation. This statement causes the subdirectory to be removed if the project is deinstalled.
Clean(docdir, os.path.join(docdir, projectname))
env.Clone([key=val, ...])
Example:
env2 = env.Clone() env3 = env.Clone(CCFLAGS='-g')
Additionally, a list of tools and a toolpath may be specified, as in the Environment constructor:
def MyTool(env):
env['FOO'] = 'bar' env4 = env.Clone(tools=['msvc', MyTool])
The parse_flags keyword argument is also recognized to allow merging command-line style arguments into the appropriate construction variables (see env.MergeFlags).
# create an environment for compiling programs that use wxWidgets wx_env = env.Clone(parse_flags='!wx-config --cflags --cxxflags')
Command(target, source, action, [key=val, ...]), env.Command(target, source, action, [key=val, ...])
The Command function accepts source_scanner, target_scanner, source_factory, and target_factory keyword arguments. These arguments can be used to specify a Scanner object that will be used to apply a custom scanner for a source or target. For example, the global DirScanner object can be used if any of the sources will be directories that must be scanned on-disk for changes to files that aren't already specified in other Builder of function calls. The *_factory arguments take a factory function that Command will use to turn any sources or targets specified as strings into SCons Nodes. See the manpage section "Builder Objects" for more information about how these arguments work in a Builder.
Any other keyword arguments specified override any same-named existing construction variables.
An action can be an external command, specified as a string, or a callable Python object; see the manpage section "Action Objects" for more complete information. Also note that a string specifying an external command may be preceded by an at-sign (@) to suppress printing the command in question, or by a hyphen (-) to ignore the exit status of the external command.
Examples:
env.Command(
target='foo.out',
source='foo.in',
action="$FOO_BUILD < $SOURCES > $TARGET" ) env.Command(
target='bar.out',
source='bar.in',
action=["rm -f $TARGET", "$BAR_BUILD < $SOURCES > $TARGET"],
ENV={'PATH': '/usr/local/bin/'}, ) import os def rename(env, target, source):
os.rename('.tmp', str(target[0])) env.Command(
target='baz.out',
source='baz.in',
action=["$BAZ_BUILD < $SOURCES > .tmp", rename], )
Note that the Command function will usually assume, by default, that the specified targets and/or sources are Files, if no other part of the configuration identifies what type of entries they are. If necessary, you can explicitly specify that targets or source nodes should be treated as directories by using the Dir or env.Dir functions.
Examples:
env.Command('ddd.list', Dir('ddd'), 'ls -l $SOURCE > $TARGET')
env['DISTDIR'] = 'destination/directory'
env.Command(env.Dir('$DISTDIR')), None, make_distdir)
Also note that SCons will usually automatically create any directory necessary to hold a target file, so you normally don't need to create directories by hand.
Configure(env, [custom_tests, conf_dir, log_file, config_h]), env.Configure([custom_tests, conf_dir, log_file, config_h])
Decider(function), env.Decider(function)
"timestamp-newer"
"timestamp-match"
"content"
"content-timestamp"
Examples:
# Use exact timestamp matches by default.
Decider('timestamp-match')
# Use hash content signatures for any targets built
# with the attached construction environment.
env.Decider('content')
In addition to the above already-available functions, the function argument may be a Python function you supply. Such a function must accept the following four arguments:
dependency
target
prev_ni
repo_node
The function should return a value which evaluates True if the dependency has "changed" since the last time the target was built (indicating that the target should be rebuilt), and a value which evaluates False otherwise (indicating that the target should not be rebuilt). Note that the decision can be made using whatever criteria are appopriate. Ignoring some or all of the function arguments is perfectly normal.
Example:
def my_decider(dependency, target, prev_ni, repo_node=None):
return not os.path.exists(str(target)) env.Decider(my_decider)
Default(target[, ...]), env.Default(target[, ...])
target may be one or more strings, a list of strings, a NodeList as returned by a Builder, or None. A string target may be the name of a file or directory, or a target previously defined by a call to Alias (defining the alias later will still create the alias, but it will not be recognized as a default). Calls to Default are additive. A target of None will clear any existing default target list; subsequent calls to Default will add to the (now empty) default target list like normal.
Both forms of this call affect the same global list of default targets; the construction environment method applies construction variable expansion to the targets.
The current list of targets added using Default is available in the DEFAULT_TARGETS list (see below).
Examples:
Default('foo', 'bar', 'baz')
env.Default(['a', 'b', 'c'])
hello = env.Program('hello', 'hello.c')
env.Default(hello)
DefaultEnvironment([**kwargs])
The default environment is a singleton, so the keyword arguments affect it only on the first call, on subsequent calls the already-constructed object is returned and any keyword arguments are silently ignored. The default environment can be modified after instantiation in the same way as any construction environment. Modifying the default environment has no effect on the construction environment constructed by an Environment or Clone call.
Depends(target, dependency), env.Depends(target, dependency)
Example:
env.Depends('foo', 'other-input-file-for-foo')
mylib = env.Library('mylib.c')
installed_lib = env.Install('lib', mylib)
bar = env.Program('bar.c')
# Arrange for the library to be copied into the installation
# directory before trying to build the "bar" program.
# (Note that this is for example only. A "real" library
# dependency would normally be configured through the $LIBS
# and $LIBPATH variables, not using an env.Depends() call.)
env.Depends(bar, installed_lib)
env.Detect(progs)
env.Dictionary([vars])
Example:
cvars = env.Dictionary()
cc_values = env.Dictionary('CC', 'CCFLAGS', 'CCCOM')
Dir(name, [directory]), env.Dir(name, [directory])
If name is a single pathname, the corresponding node is returned. If name is a list, SCons returns a list of nodes. Construction variables are expanded in name.
Directory Nodes can be used anywhere you would supply a string as a directory name to a Builder method or function. Directory Nodes have attributes and methods that are useful in many situations; see manpage section "File and Directory Nodes" for more information.
env.Dump([key], [format])
pretty
json
If key is None (the default) the entire dictionary of construction variables is serialized. If supplied, it is taken as the name of a construction variable whose value is serialized.
This SConstruct:
env=Environment()
print(env.Dump('CCCOM'))
will print:
'$CC -c -o $TARGET $CCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS $SOURCES'
While this SConstruct:
env = Environment() print(env.Dump())
will print:
{ 'AR': 'ar',
'ARCOM': '$AR $ARFLAGS $TARGET $SOURCES\n$RANLIB $RANLIBFLAGS $TARGET',
'ARFLAGS': ['r'],
'AS': 'as',
'ASCOM': '$AS $ASFLAGS -o $TARGET $SOURCES',
'ASFLAGS': [],
...
EnsurePythonVersion(major, minor)
Example:
EnsurePythonVersion(2,2)
EnsureSConsVersion(major, minor, [revision])
Examples:
EnsureSConsVersion(0,14) EnsureSConsVersion(0,96,90)
Environment([key=value, ...]), env.Environment([key=value, ...])
Execute(action, [actionargs ...]), env.Execute(action, [actionargs ...])
Execute(Copy('file.out', 'file.in'))
Execute performs its action immediately, as part of the SConscript-reading phase. There are no sources or targets declared in an Execute call, so any objects it manipulates will not be tracked as part of the SCons dependency graph. In the example above, neither file.out nor file.in will be tracked objects.
Execute returns the exit value of the command or return value of the Python function. scons prints an error message if the executed action fails (exits with or returns a non-zero value), however it does not, automatically terminate the build for such a failure. If you want the build to stop in response to a failed Execute call, you must explicitly check for a non-zero return value:
if Execute("mkdir sub/dir/ectory"):
# The mkdir failed, don't try to build.
Exit(1)
Exit([value])
Export([vars...], [key=value...]), env.Export([vars...], [key=value...])
Export calls are cumulative. Specifying a previously exported variable will overwrite the earlier value. Both local variables and global variables can be exported.
Examples:
env = Environment()
# Make env available for all SConscript files to Import().
Export("env")
package = 'my_name'
# Make env and package available for all SConscript files:.
Export("env", "package")
# Make env and package available for all SConscript files:
Export(["env", "package"])
# Make env available using the name debug:
Export(debug=env)
# Make env available using the name debug:
Export({"debug": env})
Note that the SConscript function supports an exports argument that allows exporting a variable or set of variables to a specific SConscript file or files. See the description below.
File(name, [directory]), env.File(name, [directory])
If name is a single pathname, the corresponding node is returned. If name is a list, SCons returns a list of nodes. Construction variables are expanded in name.
File Nodes can be used anywhere you would supply a string as a file name to a Builder method or function. File Nodes have attributes and methods that are useful in many situations; see manpage section "File and Directory Nodes" for more information.
FindFile(file, dirs), env.FindFile(file, dirs)
Example:
foo = env.FindFile('foo', ['dir1', 'dir2'])
FindInstalledFiles(), env.FindInstalledFiles()
This function serves as a convenient method to select the contents of a binary package.
Example:
Install('/bin', ['executable_a', 'executable_b'])
# will return the file node list
# ['/bin/executable_a', '/bin/executable_b']
FindInstalledFiles()
Install('/lib', ['some_library'])
# will return the file node list
# ['/bin/executable_a', '/bin/executable_b', '/lib/some_library']
FindInstalledFiles()
FindPathDirs(variable)
Note that use of FindPathDirs is generally preferable to writing your own path_function for the following reasons: 1) The returned list will contain all appropriate directories found in source trees (when VariantDir is used) or in code repositories (when Repository or the -Y option are used). 2) scons will identify expansions of variable that evaluate to the same list of directories as, in fact, the same list, and avoid re-scanning the directories for files, when possible.
Example:
def my_scan(node, env, path, arg):
# Code to scan file contents goes here...
return include_files scanner = Scanner(name = 'myscanner',
function = my_scan,
path_function = FindPathDirs('MYPATH'))
FindSourceFiles(node='"."'), env.FindSourceFiles(node='"."')
This function is a convenient method to select the contents of a Source Package.
Example:
Program('src/main_a.c')
Program('src/main_b.c')
Program('main_c.c')
# returns ['main_c.c', 'src/main_a.c', 'SConstruct', 'src/main_b.c']
FindSourceFiles()
# returns ['src/main_b.c', 'src/main_a.c' ]
FindSourceFiles('src')
As you can see build support files (SConstruct in the above example) will also be returned by this function.
Flatten(sequence), env.Flatten(sequence)
Examples:
foo = Object('foo.c')
bar = Object('bar.c')
# Because `foo' and `bar' are lists returned by the Object() Builder,
# `objects' will be a list containing nested lists:
objects = ['f1.o', foo, 'f2.o', bar, 'f3.o']
# Passing such a list to another Builder is all right because
# the Builder will flatten the list automatically:
Program(source = objects)
# If you need to manipulate the list directly using Python, you need to
# call Flatten() yourself, or otherwise handle nested lists:
for object in Flatten(objects):
print(str(object))
GetBuildFailures()
.node The node that was being built when the build failure occurred.
.status The numeric exit status returned by the command or Python function that failed when trying to build the specified Node.
.errstr The SCons error string describing the build failure. (This is often a generic message like "Error 2" to indicate that an executed command exited with a status of 2.)
.filename The name of the file or directory that actually caused the failure. This may be different from the .node attribute. For example, if an attempt to build a target named sub/dir/target fails because the sub/dir directory could not be created, then the .node attribute will be sub/dir/target but the .filename attribute will be sub/dir.
.executor The SCons Executor object for the target Node being built. This can be used to retrieve the construction environment used for the failed action.
.action The actual SCons Action object that failed. This will be one specific action out of the possible list of actions that would have been executed to build the target.
.command The actual expanded command that was executed and failed, after expansion of $TARGET, $SOURCE, and other construction variables.
Note that the GetBuildFailures function will always return an empty list until any build failure has occurred, which means that GetBuildFailures will always return an empty list while the SConscript files are being read. Its primary intended use is for functions that will be executed before SCons exits by passing them to the standard Python atexit.register() function. Example:
import atexit def print_build_failures():
from SCons.Script import GetBuildFailures
for bf in GetBuildFailures():
print("%s failed: %s" % (bf.node, bf.errstr)) atexit.register(print_build_failures)
GetBuildPath(file, [...]), env.GetBuildPath(file, [...])
GetLaunchDir()
GetOption(name), env.GetOption(name)
name can be an entry from the following table, which shows the corresponding command line arguments that could affect the value. name can be also be the destination variable name from a project-specific option added using the AddOption function, as long as that addition has been processed prior to the GetOption call in the SConscript files.
| Query name | Command-line options | Notes |
| cache_debug | --cache-debug | |
| cache_disable | --cache-disable, --no-cache | |
| cache_force | --cache-force, --cache-populate | |
| cache_readonly | --cache-readonly | |
| cache_show | --cache-show | |
| clean | -c, --clean, --remove | |
| climb_up | -D -U -u --up --search_up | |
| config | --config | |
| debug | --debug | |
| directory | -C, --directory | |
| diskcheck | --diskcheck | |
| duplicate | --duplicate | |
| enable_virtualenv | --enable-virtualenv | |
| experimental | --experimental | since 4.2 |
| file | -f, --file, --makefile, --sconstruct | |
| hash_format | --hash-format | since 4.2 |
| help | -h, --help | |
| ignore_errors | -i, --ignore-errors | |
| ignore_virtualenv | --ignore-virtualenv | |
| implicit_cache | --implicit-cache | |
| implicit_deps_changed | --implicit-deps-changed | |
| implicit_deps_unchanged | --implicit-deps-unchanged | |
| include_dir | -I, --include-dir | |
| install_sandbox | --install-sandbox | Available only if the install tool has been called |
| keep_going | -k, --keep-going | |
| max_drift | --max-drift | |
| md5_chunksize | --hash-chunksize, --md5-chunksize | --hash-chunksize since 4.2 |
| no_exec | -n, --no-exec, --just-print, --dry-run, --recon | |
| no_progress | -Q | |
| num_jobs | -j, --jobs | |
| package_type | --package-type | Available only if the packaging tool has been called |
| profile_file | --profile | |
| question | -q, --question | |
| random | --random | |
| repository | -Y, --repository, --srcdir | |
| silent | -s, --silent, --quiet | |
| site_dir | --site-dir, --no-site-dir | |
| stack_size | --stack-size | |
| taskmastertrace_file | --taskmastertrace | |
| tree_printers | --tree | |
| warn | --warn, --warning |
Glob(pattern, [ondisk=True, source=False, strings=False, exclude=None]), env.Glob(pattern, [ondisk=True, source=False, strings=False, exclude=None])
pattern can contain POSIX-style shell metacharacters for matching:
| Pattern | Meaning |
| * | matches everything |
| ? | matches any single character |
| [seq] | matches any character in seq (can be a list or a range). |
| [!seq] | matches any character not in seq |
For a literal match, wrap the metacharacter in brackets to escape the normal behavior. For example, '[?]' matches the character '?'.
Filenames starting with a dot are specially handled - they can only be matched by patterns that start with a dot (or have a dot immediately following a pathname separator character, or slash), they are not not matched by the metacharacters. Metacharacter matches also do not span directory separators.
Glob understands repositories (see the Repository function) and source directories (see the VariantDir function) and returns a Node (or string, if so configured) match in the local (SConscript) directory if a matching Node is found anywhere in a corresponding repository or source directory.
If the optional ondisk argument evaluates false, the search for matches on disk is disabled, and only matches from already-configured File or Dir Nodes are returned. The default is to return Nodes for matches on disk as well.
If the optional source argument evaluates true, and the local directory is a variant directory, then Glob returnes Nodes from the corresponding source directory, rather than the local directory.
If the optional strings argument evaluates true, Glob returns matches as strings, rather than Nodes. The returned strings will be relative to the local (SConscript) directory. (Note that while this may make it easier to perform arbitrary manipulation of file names, it loses the context SCons would have in the Node, so if the returned strings are passed to a different SConscript file, any Node translation there will be relative to that SConscript directory, not to the original SConscript directory.)
The optional exclude argument may be set to a pattern or a list of patterns descibing files or directories to filter out of the match list. Elements matching a least one specified pattern will be excluded. These patterns use the same syntax as for pattern.
Examples:
Program("foo", Glob("*.c"))
Zip("/tmp/everything", Glob(".??*") + Glob("*"))
sources = Glob("*.cpp", exclude=["os_*_specific_*.cpp"]) \
+ Glob("os_%s_specific_*.cpp" % currentOS)
Help(text, append=False), env.Help(text, append=False)
For the first call to Help only, if append is False (the default) any local help message generated through AddOption calls is replaced. If append is True, text is appended to the existing help text.
Ignore(target, dependency), env.Ignore(target, dependency)
Ignore can also be used to remove a target from the default build by specifying the directory the target will be built in as target and the file you want to skip selecting for building as dependency. Note that this only removes the target from the default target selection algorithm: if it is a dependency of another object being built SCons still builds it normally. See the third and forth examples below.
Examples:
env.Ignore('foo', 'foo.c')
env.Ignore('bar', ['bar1.h', 'bar2.h'])
env.Ignore('.', 'foobar.obj')
env.Ignore('bar', 'bar/foobar.obj')
Import(vars...), env.Import(vars...)
Examples:
Import("env")
Import("env", "variable")
Import(["env", "variable"])
Import("*")
Literal(string), env.Literal(string)
Local(targets), env.Local(targets)
env.MergeFlags(arg, [unique])
If unique is true (the default), duplicate values are not stored. When eliminating duplicate values, any construction variables that end with the string PATH keep the left-most unique value. All other construction variables keep the right-most unique value. If unique is false, values are added even if they are duplicates.
Examples:
# Add an optimization flag to $CCFLAGS.
env.MergeFlags('-O3')
# Combine the flags returned from running pkg-config with an optimization
# flag and merge the result into the construction variables.
env.MergeFlags(['!pkg-config gtk+-2.0 --cflags', '-O3'])
# Combine an optimization flag with the flags returned from running pkg-config
# twice and merge the result into the construction variables.
env.MergeFlags(
[
'-O3',
'!pkg-config gtk+-2.0 --cflags --libs',
'!pkg-config libpng12 --cflags --libs',
]
)
NoCache(target, ...), env.NoCache(target, ...)
Multiple files should be specified either as separate arguments to the NoCache method, or as a list. NoCache will also accept the return value of any of the construction environment Builder methods.
Calling NoCache on directories and other non-File Node types has no effect because only File Nodes are cached.
Examples:
NoCache('foo.elf')
NoCache(env.Program('hello', 'hello.c'))
NoClean(target, ...), env.NoClean(target, ...)
Multiple files or directories should be specified either as separate arguments to the NoClean method, or as a list. NoClean will also accept the return value of any of the construction environment Builder methods.
Calling NoClean for a target overrides calling Clean for the same target, and any targets passed to both functions will not be removed by the -c option.
Examples:
NoClean('foo.elf')
NoClean(env.Program('hello', 'hello.c'))
env.ParseConfig(command, [function, unique])
command is executed using the SCons execution environment (that is, the construction variable $ENV in the current construction environment). If command needs additional information to operate properly, that needs to be set in the execution environment. For example, pkg-config may need a custom value set in the PKG_CONFIG_PATH environment variable.
env.MergeFlags needs to understand the output produced by command in order to distribute it to appropriate construction variables. env.MergeFlags uses a separate function to do that processing - see env.ParseFlags for the details, including a a table of options and corresponding construction variables. To provide alternative processing of the output of command, you can suppply a custom function, which must accept three arguments: the construction environment to modify, a string argument containing the output from running command, and the optional unique flag.
ParseDepends(filename, [must_exist, only_one]), env.ParseDepends(filename, [must_exist, only_one])
By default, it is not an error if filename does not exist. The optional must_exist argument may be set to True to have SCons raise an exception if the file does not exist, or is otherwise inaccessible.
The optional only_one argument may be set to True to have SCons raise an exception if the file contains dependency information for more than one target. This can provide a small sanity check for files intended to be generated by, for example, the gcc -M flag, which should typically only write dependency information for one output file into a corresponding .d file.
filename and all of the files listed therein will be interpreted relative to the directory of the SConscript file which calls the ParseDepends function.
env.ParseFlags(flags, ...)
If the first character in any string is an exclamation mark (!), the rest of the string is executed as a command, and the output from the command is parsed as GCC tool chain command-line flags and added to the resulting dictionary. This can be used to call a *-config command typical of the POSIX programming environment (for example, pkg-config). Note that such a command is executed using the SCons execution environment; if the command needs additional information, that information needs to be explicitly provided. See ParseConfig for more details.
Flag values are translated according to the prefix found, and added to the following construction variables:
-arch CCFLAGS, LINKFLAGS -D CPPDEFINES -framework FRAMEWORKS -frameworkdir= FRAMEWORKPATH -fmerge-all-constants CCFLAGS, LINKFLAGS -fopenmp CCFLAGS, LINKFLAGS -fsanitize CCFLAGS, LINKFLAGS -include CCFLAGS -imacros CCFLAGS -isysroot CCFLAGS, LINKFLAGS -isystem CCFLAGS -iquote CCFLAGS -idirafter CCFLAGS -I CPPPATH -l LIBS -L LIBPATH -mno-cygwin CCFLAGS, LINKFLAGS -mwindows LINKFLAGS -openmp CCFLAGS, LINKFLAGS -pthread CCFLAGS, LINKFLAGS -std= CFLAGS -Wa, ASFLAGS, CCFLAGS -Wl,-rpath= RPATH -Wl,-R, RPATH -Wl,-R RPATH -Wl, LINKFLAGS -Wp, CPPFLAGS - CCFLAGS + CCFLAGS, LINKFLAGS
Any other strings not associated with options are assumed to be the names of libraries and added to the $LIBS construction variable.
Examples (all of which produce the same result):
dict = env.ParseFlags('-O2 -Dfoo -Dbar=1')
dict = env.ParseFlags('-O2', '-Dfoo', '-Dbar=1')
dict = env.ParseFlags(['-O2', '-Dfoo -Dbar=1'])
dict = env.ParseFlags('-O2', '!echo -Dfoo -Dbar=1')
Platform(plat), env.Platform(plat)
Example:
env = Environment(platform=Platform('win32'))
When called as a method of an environment, calls the platform object indicated by plat to update that environment.
env.Platform('posix')
See the manpage section "Construction Environments" for more details.
Precious(target, ...), env.Precious(target, ...)
env.Prepend(key=val, [...])
Example:
env.Prepend(CCFLAGS='-g ', FOO=['foo.yyy'])
See also env.Append, env.AppendUnique and env.PrependUnique.
env.PrependENVPath(name, newpath, [envname, sep, delete_existing=True])
Example:
print('before:', env['ENV']['INCLUDE'])
include_path = '/foo/bar:/foo'
env.PrependENVPath('INCLUDE', include_path)
print('after:', env['ENV']['INCLUDE'])
Yields:
before: /biz:/foo after: /foo/bar:/foo:/biz
See also env.AppendENVPath.
env.PrependUnique(key=val, [...], [delete_existing=False])
Example:
env.PrependUnique(CCFLAGS='-g', FOO=['foo.yyy'])
See also env.Append, env.AppendUnique and env.Prepend.
Progress(callable, [interval]), Progress(string, [interval, file, overwrite]), Progress(list_of_strings, [interval, file, overwrite])
If the first specified argument is a Python callable (a function or an object that has a __call__ method), the function will be called once every interval times a Node is evaluated (default 1). The callable will be passed the evaluated Node as its only argument. (For future compatibility, it's a good idea to also add *args and **kwargs as arguments to your function or method signatures. This will prevent the code from breaking if SCons ever changes the interface to call the function with additional arguments in the future.)
An example of a simple custom progress function that prints a string containing the Node name every 10 Nodes:
def my_progress_function(node, *args, **kwargs):
print('Evaluating node %s!' % node) Progress(my_progress_function, interval=10)
A more complicated example of a custom progress display object that prints a string containing a count every 100 evaluated Nodes. Note the use of \r (a carriage return) at the end so that the string will overwrite itself on a display:
import sys class ProgressCounter(object):
count = 0
def __call__(self, node, *args, **kw):
self.count += 100
sys.stderr.write('Evaluated %s nodes\r' % self.count) Progress(ProgressCounter(), interval=100)
If the first argument to Progress is a string or list of strings, it is taken as text to be displayed every interval evaluated Nodes. If the first argument is a list of strings, then each string in the list will be displayed in rotating fashion every interval evaluated Nodes.
The default is to print the string on standard output. An alternate output stream may be specified with the file keyword argument, which the caller must pass already opened.
The following will print a series of dots on the error output, one dot for every 100 evaluated Nodes:
import sys
Progress('.', interval=100, file=sys.stderr)
If the string contains the verbatim substring $TARGET;, it will be replaced with the Node. Note that, for performance reasons, this is not a regular SCons variable substition, so you can not use other variables or use curly braces. The following example will print the name of every evaluated Node, using a carriage return) (\r) to cause each line to overwritten by the next line, and the overwrite keyword argument (default False) to make sure the previously-printed file name is overwritten with blank spaces:
import sys
Progress('$TARGET\r', overwrite=True)
A list of strings can be used to implement a "spinner" on the user's screen as follows, changing every five evaluated Nodes:
Progress(['-\r', '\\\r', '|\r', '/\r'], interval=5)
Pseudo(target, ...), env.Pseudo(target, ...)
PyPackageDir(modulename), env.PyPackageDir(modulename)
If modulename is a list, SCons returns a list of Dir nodes. Construction variables are expanded in modulename.
env.Replace(key=val, [...])
Example:
env.Replace(CCFLAGS='-g', FOO='foo.xxx')
Repository(directory), env.Repository(directory)
To scons, a repository is a copy of the source tree, from the top-level directory on down, which may contain both source files and derived files that can be used to build targets in the local source tree. The canonical example would be an official source tree maintained by an integrator. If the repository contains derived files, then the derived files should have been built using scons, so that the repository contains the necessary signature information to allow scons to figure out when it is appropriate to use the repository copy of a derived file, instead of building one locally.
Note that if an up-to-date derived file already exists in a repository, scons will not make a copy in the local directory tree. In order to guarantee that a local copy will be made, use the Local method.
Requires(target, prerequisite), env.Requires(target, prerequisite)
Example:
env.Requires('foo', 'file-that-must-be-built-before-foo')
Return([vars..., stop=True])
By default Return stops processing the current SConscript and returns immediately. The optional stop keyword argument may be set to a false value to continue processing the rest of the SConscript file after the Return call (this was the default behavior prior to SCons 0.98.) However, the values returned are still the values of the variables in the named vars at the point Return was called.
Examples:
# Returns no values (evaluates False)
Return()
# Returns the value of the 'foo' Python variable.
Return("foo")
# Returns the values of the Python variables 'foo' and 'bar'.
Return("foo", "bar")
# Returns the values of Python variables 'val1' and 'val2'.
Return('val1 val2')
Scanner(function, [name, argument, skeys, path_function, node_class, node_factory, scan_check, recursive]), env.Scanner(function, [name, argument, skeys, path_function, node_class, node_factory, scan_check, recursive])
SConscript(scripts, [exports, variant_dir, duplicate, must_exist]), env.SConscript(scripts, [exports, variant_dir, duplicate, must_exist]), SConscript(dirs=subdirs, [name=scriptname, exports, variant_dir, duplicate, must_exist]), env.SConscript(dirs=subdirs, [name=scriptname, exports, variant_dir, duplicate, must_exist])
The first calling style is to supply one or more SConscript file names as the first (positional) argument. A single script may be specified as a string; multiple scripts must be specified as a list of strings (either explicitly or as created by a function like Split). Examples:
SConscript('SConscript') # run SConscript in the current directory
SConscript('src/SConscript') # run SConscript in the src directory
SConscript(['src/SConscript', 'doc/SConscript'])
config = SConscript('MyConfig.py')
The other calling style is to omit the positional argument naming scripts and instead specify a list of directory names using the dirs keyword argument. In this case, scons will execute a subsidiary configuration file named SConscript in each of the specified directories. You may specify a name other than SConscript by supplying an optional name=scriptname keyword argument. The first three examples below have the same effect as the first three examples above:
SConscript(dirs='.') # run SConscript in the current directory SConscript(dirs='src') # run SConscript in the src directory SConscript(dirs=['src', 'doc']) SConscript(dirs=['sub1', 'sub2'], name='MySConscript')
The optional exports keyword argument provides a string or list of strings representing variable names, or a dictionary of named values, to export. For the first calling style only, a second positional argument will be interpreted as exports; the second calling style must use the keyword argument form for exports. These variables are locally exported only to the called SConscript file(s) and do not affect the global pool of variables managed by the Export function. The subsidiary SConscript files must use the Import function to import the variables. Examples:
foo = SConscript('sub/SConscript', exports='env')
SConscript('dir/SConscript', exports=['env', 'variable'])
SConscript(dirs='subdir', exports='env variable')
SConscript(dirs=['one', 'two', 'three'], exports='shared_info')
If the optional variant_dir argument is present, it causes an effect equivalent to the VariantDir function, but in effect only within the scope of the SConscript call. The variant_dir argument is interpreted relative to the directory of the calling SConscript file. The source directory is the directory in which the called SConscript file resides and the SConscript file is evaluated as if it were in the variant_dir directory. Thus:
SConscript('src/SConscript', variant_dir='build')
is equivalent to:
VariantDir('build', 'src')
SConscript('build/SConscript')
If the sources are in the same directory as the SConstruct,
SConscript('SConscript', variant_dir='build')
is equivalent to:
VariantDir('build', '.')
SConscript('build/SConscript')
The optional duplicate argument is interpreted as for VariantDir. If the variant_dir argument is omitted, the duplicate argument is ignored. See the description of VariantDir for additional details and restrictions.
If the optional must_exist is True, causes an exception to be raised if a requested SConscript file is not found. The current default is False, causing only a warning to be emitted, but this default is deprecated (since 3.1). For scripts which truly intend to be optional, transition to explicitly supplying must_exist=False to the SConscript call.
Here are some composite examples:
# collect the configuration information and use it to build src and doc
shared_info = SConscript('MyConfig.py')
SConscript('src/SConscript', exports='shared_info')
SConscript('doc/SConscript', exports='shared_info')
# build debugging and production versions. SConscript
# can use Dir('.').path to determine variant.
SConscript('SConscript', variant_dir='debug', duplicate=0)
SConscript('SConscript', variant_dir='prod', duplicate=0)
# build debugging and production versions. SConscript
# is passed flags to use.
opts = { 'CPPDEFINES' : ['DEBUG'], 'CCFLAGS' : '-pgdb' }
SConscript('SConscript', variant_dir='debug', duplicate=0, exports=opts)
opts = { 'CPPDEFINES' : ['NODEBUG'], 'CCFLAGS' : '-O' }
SConscript('SConscript', variant_dir='prod', duplicate=0, exports=opts)
# build common documentation and compile for different architectures
SConscript('doc/SConscript', variant_dir='build/doc', duplicate=0)
SConscript('src/SConscript', variant_dir='build/x86', duplicate=0)
SConscript('src/SConscript', variant_dir='build/ppc', duplicate=0)
SConscript returns the values of any variables named by the executed SConscript file(s) in arguments to the Return function. If a single SConscript call causes multiple scripts to be executed, the return value is a tuple containing the returns of each of the scripts. If an executed script does not explicitly call Return, it returns None.
SConscriptChdir(value)
Example:
SConscriptChdir(False)
SConscript('foo/SConscript') # will not chdir to foo
SConscriptChdir(True)
SConscript('bar/SConscript') # will chdir to bar
SConsignFile([name, dbm_module]), env.SConsignFile([name, dbm_module])
The optional name argument is the base name of the database file(s). If not an absolute path name, these are placed relative to the directory containing the top-level SConstruct file. The default is .sconsign. The actual database file(s) stored on disk may have an appropriate suffix appended by the chosen dbm_module
The optional dbm_module argument specifies which Python database module to use for reading/writing the file. The module must be imported first; then the imported module name is passed as the argument. The default is a custom SCons.dblite module that uses pickled Python data structures, which works on all Python versions. See documentation of the Python dbm module for other available types.
If called with no arguments, the database will default to .sconsign.dblite in the top directory of the project, which is also the default if if SConsignFile is not called.
The setting is global, so the only difference between the global function and the environment method form is variable expansion on name. There should only be one active call to this function/method in a given build setup.
If name is set to None, scons will store file signatures in a separate .sconsign file in each directory, not in a single combined database file. This is a backwards-compatibility meaure to support what was the default behavior prior to SCons 0.97 (i.e. before 2008). Use of this mode is discouraged and may be deprecated in a future SCons release.
Examples:
# Explicitly stores signatures in ".sconsign.dblite"
# in the top-level SConstruct directory (the default behavior).
SConsignFile()
# Stores signatures in the file "etc/scons-signatures"
# relative to the top-level SConstruct directory.
# SCons will add a database suffix to this name.
SConsignFile("etc/scons-signatures")
# Stores signatures in the specified absolute file name.
# SCons will add a database suffix to this name.
SConsignFile("/home/me/SCons/signatures")
# Stores signatures in a separate .sconsign file
# in each directory.
SConsignFile(None)
# Stores signatures in a GNU dbm format .sconsign file
import dbm.gnu
SConsignFile(dbm_module=dbm.gnu)
env.SetDefault(key=val, [...])
env.SetDefault(FOO='foo') if 'FOO' not in env:
env['FOO'] = 'foo'
SetOption(name, value), env.SetOption(name, value)
See the documentation in the manpage for the corresponding command line option for information about each specific option. The value parameter is mandatory, for option values which are boolean in nature (that is, the command line option does not take an argument) use a value which evaluates to true (e.g. True, 1) or false (e.g. False, 0).
Options which affect the reading and processing of SConscript files are not settable using SetOption since those files must be read in order to find the SetOption call in the first place.
The settable variables with their associated command-line options are:
| Settable name | Command-line options | Notes |
| clean | -c, --clean, --remove | |
| diskcheck | --diskcheck | |
| duplicate | --duplicate | |
| experimental | --experimental | since 4.2 |
| hash_chunksize | --hash-chunksize | Actually sets md5_chunksize. since 4.2 |
| hash_format | --hash-format | since 4.2 |
| help | -h, --help | |
| implicit_cache | --implicit-cache | |
| implicit_deps_changed | --implicit-deps-changed | Also sets implicit_cache. (settable since 4.2) |
| implicit_deps_unchanged | --implicit-deps-unchanged | Also sets implicit_cache. (settable since 4.2) |
| max_drift | --max-drift | |
| md5_chunksize | --md5-chunksize | |
| no_exec | -n, --no-exec, --just-print, --dry-run, --recon | |
| no_progress | -Q | See [6] |
| num_jobs | -j, --jobs | |
| random | --random | |
| silent | -s, --silent, --quiet | |
| stack_size | --stack-size | |
| warn | --warn | |
| ---- [a] If no_progress is set via SetOption in an SConscript file (but not if set in a site_init.py file) there will still be an initial status message about reading SConscript files since SCons has to start reading them before it can see the SetOption. | ||
Example:
SetOption('max_drift', 0)
SideEffect(side_effect, target), env.SideEffect(side_effect, target)
Because multiple build commands may update the same side effect file, by default the side_effect target is not automatically removed when the target is removed by the -c option. (Note, however, that the side_effect might be removed as part of cleaning the directory in which it lives.) If you want to make sure the side_effect is cleaned whenever a specific target is cleaned, you must specify this explicitly with the Clean or env.Clean function.
This function returns the list of side effect Node objects that were successfully added. If the list of side effects contained any side effects that had already been added, they are not added and included in the returned list.
Split(arg), env.Split(arg)
Example:
files = Split("f1.c f2.c f3.c")
files = env.Split("f4.c f5.c f6.c")
files = Split("""
f7.c
f8.c
f9.c
""")
env.subst(input, [raw, target, source, conv])
By default, leading or trailing white space will be removed from the result, and all sequences of white space will be compressed to a single space character. Additionally, any $( and $) character sequences will be stripped from the returned string, The optional raw argument may be set to 1 if you want to preserve white space and $(-$) sequences. The raw argument may be set to 2 if you want to additionally discard all characters between any $( and $) pairs (as is done for signature calculation).
If input is a sequence (list or tuple), the individual elements of the sequence will be expanded, and the results will be returned as a list.
The optional target and source keyword arguments must be set to lists of target and source nodes, respectively, if you want the $TARGET, $TARGETS, $SOURCE and $SOURCES to be available for expansion. This is usually necessary if you are calling env.subst from within a Python function used as an SCons action.
Returned string values or sequence elements are converted to their string representation by default. The optional conv argument may specify a conversion function that will be used in place of the default. For example, if you want Python objects (including SCons Nodes) to be returned as Python objects, you can use a Python lambda expression to pass in an unnamed function that simply returns its unconverted argument.
Example:
print(env.subst("The C compiler is: $CC"))
def compile(target, source, env):
sourceDir = env.subst(
"${SOURCE.srcdir}",
target=target,
source=source
)
source_nodes = env.subst('$EXPAND_TO_NODELIST', conv=lambda x: x)
Tag(node, tags)
Examples:
# makes sure the built library will be installed with 644 file access mode
Tag(Library('lib.c'), UNIX_ATTR="0o644")
# marks file2.txt to be a documentation file
Tag('file2.txt', DOC)
Tool(name, [toolpath, **kwargs]), env.Tool(name, [toolpath, **kwargs])
When called, the tool object updates a construction environment with construction variables and arranges any other initialization needed to use the mechanisms that tool describes.
When the env.Tool form is used, the tool object is automatically called to update env and the value of tool is appended to the $TOOLS construction variable in that environment.
Changed in version 4.2: env.Tool now returns the tool object, previously it did not return (i.e. returned None).
Examples:
env.Tool('gcc')
env.Tool('opengl', toolpath=['build/tools'])
When the global function Tool form is used, the tool object is constructed but not called, as it lacks the context of an environment to update. The tool object can be passed to an Environment or Clone call as part of the tools keyword argument, in which case the tool is applied to the environment being constructed, or it can be called directly, in which case a construction environment to update must be passed as the argument. Either approach will also update the $TOOLS construction variable.
Examples:
env = Environment(tools=[Tool('msvc')])
env = Environment()
msvctool = Tool('msvc')
msvctool(env) # adds 'msvc' to the TOOLS variable
gltool = Tool('opengl', toolpath = ['tools'])
gltool(env) # adds 'opengl' to the TOOLS variable
ValidateOptions([throw_exception=False])
This function should only be called after the last AddOption call in your SConscript logic.
Be aware that some tools call AddOption, if you are getting error messages for arguments that they add, you will need to ensure that you load those tools before you call ValidateOptions.
If there are any command line options not defined, calling this function will cause SCons to issue an error message and then exit with an error exit status.
If the optional throw_exception is True, ValidateOptions will raise a SConsBadOptionError exception. This would allow the calling SConscript logic can catch that exception and handle invalid options itself.
Example:
try:
ValidateOptions(throw_exception=True) except SConsBadOptionError as e:
print("Parser is SConsOptionParser:%s" % (isinstance(e.parser, SConsOptionParser)))
print("Message is :%s" % e.opt_str)
Exit(3)
This function is useful to force SCons to fail fast before you execute any expensive logic later in your build logic. For example if you specify build options via any flags, a simple typo could yield the incorrect build option throughout your entire build.
scons --compilers=mingw (the correct flag is --compiler)
Could cause SCons to run configure steps with the incorrect compiler. Costing developer time trying to track down why the configure logic failed with a compiler which should work.
New in version 4.5.0
Value(value, [built_value], [name]), env.Value(value, [built_value], [name])
The returned Value Node object has a write() method that can be used to "build" a Value Node by setting a new value. The optional built_value argument can be specified when the Value Node is created to indicate the Node should already be considered "built." There is a corresponding read() method that will return the built value of the Node.
The optional name parameter can be provided as an alternative name for the resulting Value node; this is advised if the value parameter cannot be converted to a string.
Changed in version 4.0: the name parameter was added.
Examples:
env = Environment() def create(target, source, env):
# A function that will write a 'prefix=$SOURCE'
# string into the file name specified as the
# $TARGET.
with open(str(target[0]), 'wb') as f:
f.write('prefix=' + source[0].get_contents()) # Fetch the prefix= argument, if any, from the command # line, and use /usr/local as the default. prefix = ARGUMENTS.get('prefix', '/usr/local') # Attach a .Config() builder for the above function action # to the construction environment. env['BUILDERS']['Config'] = Builder(action=create) env.Config(target='package-config', source=Value(prefix)) def build_value(target, source, env):
# A function that "builds" a Python Value by updating
# the Python value with the contents of the file
# specified as the source of the Builder call ($SOURCE).
target[0].write(source[0].get_contents()) output = env.Value('before') input = env.Value('after') # Attach a .UpdateValue() builder for the above function # action to the construction environment. env['BUILDERS']['UpdateValue'] = Builder(action=build_value) env.UpdateValue(target=Value(output), source=Value(input))
VariantDir(variant_dir, src_dir, [duplicate]), env.VariantDir(variant_dir, src_dir, [duplicate])
Note if variant_dir is not under the project top directory, target selection rules will not pick targets in the variant directory unless they are explicitly specified.
When files in variant_dir are referenced, SCons backfills as needed with files from src_dir to create a complete build directory. By default, SCons physically duplicates the source files, SConscript files, and directory structure as needed into the variant directory. Thus, a build performed in the variant directory is guaranteed to be identical to a build performed in the source directory even if intermediate source files are generated during the build, or if preprocessors or other scanners search for included files using paths relative to the source file, or if individual compilers or other invoked tools are hard-coded to put derived files in the same directory as source files. Only the files SCons calculates are needed for the build are duplicated into variant_dir. If possible on the platform, the duplication is performed by linking rather than copying. This behavior is affected by the --duplicate command-line option.
Duplicating the source files may be disabled by setting the duplicate argument to False. This will cause SCons to invoke Builders using the path names of source files in src_dir and the path names of derived files within variant_dir. This is more efficient than duplicating, and is safe for most builds; revert to duplicate=True if it causes problems.
VariantDir works most naturally when used with a subsidiary SConscript file. The subsidiary SConscript file must be called as if it were in variant_dir, regardless of the value of duplicate. When calling an SConscript file, you can use the exports keyword argument to pass parameters (individually or as an appropriately set up environment) so the SConscript can pick up the right settings for that variant build. The SConscript must Import these to use them. Example:
env1 = Environment(...settings for variant1...)
env2 = Environment(...settings for variant2...)
# run src/SConscript in two variant directories
VariantDir('build/variant1', 'src')
SConscript('build/variant1/SConscript', exports={"env": env1})
VariantDir('build/variant2', 'src')
SConscript('build/variant2/SConscript', exports={"env": env2})
See also the SConscript function for another way to specify a variant directory in conjunction with calling a subsidiary SConscript file.
More examples:
# use names in the build directory, not the source directory
VariantDir('build', 'src', duplicate=0)
Program('build/prog', 'build/source.c')
# this builds both the source and docs in a separate subtree
VariantDir('build', '.', duplicate=0)
SConscript(dirs=['build/src','build/doc'])
# same as previous example, but only uses SConscript
SConscript(dirs='src', variant_dir='build/src', duplicate=0)
SConscript(dirs='doc', variant_dir='build/doc', duplicate=0)
WhereIs(program, [path, pathext, reject]), env.WhereIs(program, [path, pathext, reject])
When called as a construction environment method, searches the paths in the path keyword argument, or if None (the default) the paths listed in the construction environment (env['ENV']['PATH']). The external environment's path list (os.environ['PATH']) is used as a fallback if the key env['ENV']['PATH'] does not exist.
On Windows systems, searches for executable programs with any of the file extensions listed in the pathext keyword argument, or if None (the default) the pathname extensions listed in the construction environment (env['ENV']['PATHEXT']). The external environment's pathname extensions list (os.environ['PATHEXT']) is used as a fallback if the key env['ENV']['PATHEXT'] does not exist.
When called as a global function, uses the external environment's path os.environ['PATH'] and path extensions os.environ['PATHEXT'], respectively, if path and pathext are None.
Will not select any path name or names in the optional reject list.
SConscript Variables¶
In addition to the global functions and methods, scons supports a number of variables that can be used in SConscript files to affect how you want the build to be performed.
ARGLIST
print("first keyword, value =", ARGLIST[0][0], ARGLIST[0][1])
print("second keyword, value =", ARGLIST[1][0], ARGLIST[1][1])
key, value = ARGLIST[2]
print("third keyword, value =", key, value)
for key, value in ARGLIST:
# process key and value
ARGUMENTS
Example:
if ARGUMENTS.get('debug', 0):
env = Environment(CCFLAGS='-g')
else:
env = Environment()
BUILD_TARGETS
The elements of this list may be strings or nodes, so you should run the list through the Python str function to make sure any Node path names are converted to strings.
Because this list may be taken from the list of targets specified using the Default function, the contents of the list may change on each successive call to Default. See the DEFAULT_TARGETS list, below, for additional information.
Example:
if 'foo' in BUILD_TARGETS:
print("Don't forget to test the `foo' program!") if 'special/program' in BUILD_TARGETS:
SConscript('special')
COMMAND_LINE_TARGETS
Example:
if 'foo' in COMMAND_LINE_TARGETS:
print("Don't forget to test the `foo' program!") if 'special/program' in COMMAND_LINE_TARGETS:
SConscript('special')
DEFAULT_TARGETS
Example:
print(str(DEFAULT_TARGETS[0])) if 'foo' in [str(t) for t in DEFAULT_TARGETS]:
print("Don't forget to test the `foo' program!")
The contents of the DEFAULT_TARGETS list change on on each successive call to the Default function:
print([str(t) for t in DEFAULT_TARGETS]) # originally []
Default('foo')
print([str(t) for t in DEFAULT_TARGETS]) # now a node ['foo']
Default('bar')
print([str(t) for t in DEFAULT_TARGETS]) # now a node ['foo', 'bar']
Default(None)
print([str(t) for t in DEFAULT_TARGETS]) # back to []
Consequently, be sure to use DEFAULT_TARGETS only after you've made all of your Default() calls, or else simply be careful of the order of these statements in your SConscript files so that you don't look for a specific default target before it's actually been added to the list.
These variables may be accessed from custom Python modules that you import into an SConscript file by adding the following to the Python module:
from SCons.Script import *
Construction Variables¶
A construction environment has an associated dictionary of construction variables that are used by built-in or user-supplied build rules. Construction variable naming must follow the same rules as Python identifier naming: the initial character must be an underscore or letter, followed by any number of underscores, letters, or digits. A construction environment is not a Python dictionary itself, but it can be indexed like one to access a construction variable:
env["CC"] = "cc"
flags = env.get("CPPDEFINES", [])
Construction variables can also be retrieved and set by using the Dictionary method of the construction environment to create an actual dictionary:
cvars = env.Dictionary() cvars["CC"] = "cc"
Construction variables can also be passed to the construction environment constructor:
env = Environment(CC="cc")
or when copying a construction environment using the Clone method:
env2 = env.Clone(CC="cl.exe")
Construction variables can also be supplied as keyword arguments to a builder, in which case those settings affect only the work done by that builder call, and not the construction environment as a whole. This concept is called an override:
env.Program('hello', 'hello.c', LIBS=['gl', 'glut'])
A number of useful construction variables are automatically defined by scons for each supported platform, and you can modify these or define any additional construction variables for your own use, taking care not to overwrite ones which SCons is using. The following is a list of the possible automatically defined construction variables.
Note the actual list available at execution time will never include all of these, as the ones detected as not being useful (wrong platform, necessary external command or files not installed, etc.) will not be set up. Correct build setups should be resilient to the possible absence of certain construction variables before using them, for example by using a Python dictionary get method to retrieve the value and taking alternative action if the return indicates the variable is unset. The env.Dump method can be called to examine the construction variables set in a particular environment.
__LDMODULEVERSIONFLAGS
__SHLIBVERSIONFLAGS
APPLELINK_COMPATIBILITY_VERSION
The value is specified as X[.Y[.Z]] where X is between 1 and 65535, Y can be omitted or between 1 and 255, Z can be omitted or between 1 and 255. This value will be derived from $SHLIBVERSION if not specified. The lowest digit will be dropped and replaced by a 0.
If the $APPLELINK_NO_COMPATIBILITY_VERSION is set then no -compatibility_version will be output.
See MacOS's ld manpage for more details
_APPLELINK_COMPATIBILITY_VERSION
APPLELINK_CURRENT_VERSION
The value is specified as X[.Y[.Z]] where X is between 1 and 65535, Y can be omitted or between 1 and 255, Z can be omitted or between 1 and 255. This value will be set to $SHLIBVERSION if not specified.
If the $APPLELINK_NO_CURRENT_VERSION is set then no -current_version will be output.
See MacOS's ld manpage for more details
_APPLELINK_CURRENT_VERSION
APPLELINK_NO_COMPATIBILITY_VERSION
This overrides $APPLELINK_COMPATIBILITY_VERSION.
APPLELINK_NO_CURRENT_VERSION
This overrides $APPLELINK_CURRENT_VERSION.
AR
ARCHITECTURE
See the Package builder.
ARCOM
ARCOMSTR
env = Environment(ARCOMSTR = "Archiving $TARGET")
ARFLAGS
AS
ASCOM
ASCOMSTR
env = Environment(ASCOMSTR = "Assembling $TARGET")
ASFLAGS
ASPPCOM
ASPPCOMSTR
env = Environment(ASPPCOMSTR = "Assembling $TARGET")
ASPPFLAGS
BIBTEX
BIBTEXCOM
BIBTEXCOMSTR
env = Environment(BIBTEXCOMSTR = "Generating bibliography $TARGET")
BIBTEXFLAGS
BUILDERS
A platform-dependent default list of builders such as Program, Library etc. is used to populate this construction variable when the construction environment is initialized via the presence/absence of the tools those builders depend on. $BUILDERS can be examined to learn which builders will actually be available at run-time.
Note that if you initialize this construction variable through assignment when the construction environment is created, that value for $BUILDERS will override any defaults:
bld = Builder(action='foobuild < $SOURCE > $TARGET')
env = Environment(BUILDERS={'NewBuilder': bld})
To instead use a new Builder object in addition to the default Builders, add your new Builder object like this:
env = Environment()
env.Append(BUILDERS={'NewBuilder': bld})
or this:
env = Environment() env['BUILDERS']['NewBuilder'] = bld
CACHEDIR_CLASS
CC
CCCOM
CCCOMSTR
env = Environment(CCCOMSTR = "Compiling static object $TARGET")
CCDEPFLAGS
This is set only by compilers which support this functionality. (gcc, clang, and msvc currently)
CCFLAGS
CCPCHFLAGS
CCPDBFLAGS
The Visual C++ compiler option that SCons uses by default to generate PDB information is /Z7. This works correctly with parallel (-j) builds because it embeds the debug information in the intermediate object files, as opposed to sharing a single PDB file between multiple object files. This is also the only way to get debug information embedded into a static library. Using the /Zi instead may yield improved link-time performance, although parallel builds will no longer work.
You can generate PDB files with the /Zi switch by overriding the default $CCPDBFLAGS variable as follows:
env['CCPDBFLAGS'] = ['${(PDB and "/Zi /Fd%s" % File(PDB)) or ""}']
An alternative would be to use the /Zi to put the debugging information in a separate .pdb file for each object file by overriding the $CCPDBFLAGS variable as follows:
env['CCPDBFLAGS'] = '/Zi /Fd${TARGET}.pdb'
CCVERSION
CFILESUFFIX
CFLAGS
CHANGE_SPECFILE
See the Package builder.
CHANGED_SOURCES
CHANGED_TARGETS
CHANGELOG
See the Package builder.
COMPILATIONDB_COMSTR
COMPILATIONDB_PATH_FILTER
The default value is an empty string '', which disables filtering.
COMPILATIONDB_USE_ABSPATH
The default value is False (use relative paths)
_concat
env['_CPPINCFLAGS'] = '${_concat(INCPREFIX, CPPPATH, INCSUFFIX, __env__, RDirs, TARGET, SOURCE, affect_signature=False)}'
CONFIGUREDIR
CONFIGURELOG
_CPPDEFFLAGS
CPPDEFINES
# Adds -Dxyz to POSIX compiler command lines, # and /Dxyz to Microsoft Visual C++ command lines. env = Environment(CPPDEFINES='xyz')
# Adds -DB=2 -DA to POSIX compiler command lines,
# and /DB=2 /DA to Microsoft Visual C++ command lines.
env = Environment(CPPDEFINES=[('B', 2), 'A'])
# Adds -DA -DB=2 to POSIX compiler command lines,
# or /DA /DB=2 to Microsoft Visual C++ command lines.
env = Environment(CPPDEFINES={'B':2, 'A':None})
Depending on how contents are added to $CPPDEFINES, it may be transformed into a compound type, for example a list containing strings, tuples and/or dictionaries. SCons can correctly expand such a compound type.
Note that SCons may call the compiler via a shell. If a macro definition contains characters such as spaces that have meaning to the shell, or is intended to be a string value, you may need to use the shell's quoting syntax to avoid interpretation by the shell before the preprocessor sees it. Function-like macros are not supported via this mechanism (and some compilers do not even implement that functionality via the command lines). When quoting, note that one set of quote characters are used to define a Python string, then quotes embedded inside that would be consumed by the shell unless escaped. These examples may help illustrate:
env = Environment(CPPDEFINES=['USE_ALT_HEADER=\\"foo_alt.h\\"'])
env = Environment(CPPDEFINES=[('USE_ALT_HEADER', '\\"foo_alt.h\\"')])
:Changed in version 4.5: SCons no longer sorts $CPPDEFINES values entered in dictionary form. Python now preserves dictionary keys in the order they are entered, so it is no longer necessary to sort them to ensure a stable command line.
CPPDEFPREFIX
CPPDEFSUFFIX
CPPFLAGS
_CPPINCFLAGS
CPPPATH
Note: directory names in $CPPPATH will be looked-up relative to the directory of the SConscript file when they are used in a command. To force scons to look-up a directory relative to the root of the source tree use the # prefix:
env = Environment(CPPPATH='#/include')
The directory look-up can also be forced using the Dir function:
include = Dir('include')
env = Environment(CPPPATH=include)
The directory list will be added to command lines through the automatically-generated $_CPPINCFLAGS construction variable, which is constructed by respectively prepending and appending the values of the $INCPREFIX and $INCSUFFIX construction variables to each directory in $CPPPATH. Any command lines you define that need the $CPPPATH directory list should include $_CPPINCFLAGS:
env = Environment(CCCOM="my_compiler $_CPPINCFLAGS -c -o $TARGET $SOURCE")
CPPSUFFIXES
[".c", ".C", ".cxx", ".cpp", ".c++", ".cc",
".h", ".H", ".hxx", ".hpp", ".hh",
".F", ".fpp", ".FPP",
".m", ".mm",
".S", ".spp", ".SPP"]
CXX
CXXCOM
CXXCOMSTR
env = Environment(CXXCOMSTR = "Compiling static object $TARGET")
CXXFILESUFFIX
CXXFLAGS
CXXVERSION
DC
DCOM
DCOMSTR
DDEBUG
DDEBUGPREFIX
DDEBUGSUFFIX
DESCRIPTION
See the Package builder.
DESCRIPTION_lang
See the Package builder.
DFILESUFFIX
DFLAGPREFIX
DFLAGS
DFLAGSUFFIX
DINCPREFIX
DINCSUFFIX
Dir
Dirs
DLIB
DLIBCOM
DLIBDIRPREFIX
DLIBDIRSUFFIX
DLIBFLAGPREFIX
DLIBFLAGSUFFIX
DLIBLINKPREFIX
DLIBLINKSUFFIX
DLINK
DLINKCOM
DLINKFLAGPREFIX
DLINKFLAGS
DLINKFLAGSUFFIX
DOCBOOK_DEFAULT_XSL_EPUB
DOCBOOK_DEFAULT_XSL_HTML
DOCBOOK_DEFAULT_XSL_HTMLCHUNKED
DOCBOOK_DEFAULT_XSL_HTMLHELP
DOCBOOK_DEFAULT_XSL_MAN
DOCBOOK_DEFAULT_XSL_PDF
DOCBOOK_DEFAULT_XSL_SLIDESHTML
DOCBOOK_DEFAULT_XSL_SLIDESPDF
DOCBOOK_FOP
DOCBOOK_FOPCOM
DOCBOOK_FOPCOMSTR
DOCBOOK_FOPFLAGS
DOCBOOK_XMLLINT
DOCBOOK_XMLLINTCOM
DOCBOOK_XMLLINTCOMSTR
DOCBOOK_XMLLINTFLAGS
DOCBOOK_XSLTPROC
DOCBOOK_XSLTPROCCOM
DOCBOOK_XSLTPROCCOMSTR
DOCBOOK_XSLTPROCFLAGS
DOCBOOK_XSLTPROCPARAMS
DPATH
DRPATHPREFIX
DRPATHSUFFIX
DSUFFIXES
DVERPREFIX
DVERSIONS
DVERSUFFIX
DVIPDF
DVIPDFCOM
DVIPDFCOMSTR
DVIPDFFLAGS
DVIPS
DVIPSFLAGS
ENV
Note that by default SCons does not propagate the environment in effect when you execute scons (the "shell environment") to the execution environment. This is so that builds will be guaranteed repeatable regardless of the environment variables set at the time scons is invoked. If you want to propagate a shell environment variable to the commands executed to build target files, you must do so explicitly. A common example is the system PATH environment variable, so that scons will find utilities the same way as the invoking shell (or other process):
import os
env = Environment(ENV={'PATH': os.environ['PATH']})
Although it is usually not recommended, you can propagate the entire shell environment in one go:
import os env = Environment(ENV=os.environ.copy())
ESCAPE
F03
F03COM
F03COMSTR
F03FILESUFFIXES
F03FLAGS
_F03INCFLAGS
F03PATH
env = Environment(F03PATH='#/include')
The directory look-up can also be forced using the Dir() function:
include = Dir('include')
env = Environment(F03PATH=include)
The directory list will be added to command lines through the automatically-generated $_F03INCFLAGS construction variable, which is constructed by appending the values of the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each directory in $F03PATH. Any command lines you define that need the F03PATH directory list should include $_F03INCFLAGS:
env = Environment(F03COM="my_compiler $_F03INCFLAGS -c -o $TARGET $SOURCE")
F03PPCOM
F03PPCOMSTR
F03PPFILESUFFIXES
F08
F08COM
F08COMSTR
F08FILESUFFIXES
F08FLAGS
_F08INCFLAGS
F08PATH
env = Environment(F08PATH='#/include')
The directory look-up can also be forced using the Dir() function:
include = Dir('include')
env = Environment(F08PATH=include)
The directory list will be added to command lines through the automatically-generated $_F08INCFLAGS construction variable, which is constructed by appending the values of the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each directory in $F08PATH. Any command lines you define that need the F08PATH directory list should include $_F08INCFLAGS:
env = Environment(F08COM="my_compiler $_F08INCFLAGS -c -o $TARGET $SOURCE")
F08PPCOM
F08PPCOMSTR
F08PPFILESUFFIXES
F77
F77COM
F77COMSTR
F77FILESUFFIXES
F77FLAGS
_F77INCFLAGS
F77PATH
env = Environment(F77PATH='#/include')
The directory look-up can also be forced using the Dir() function:
include = Dir('include')
env = Environment(F77PATH=include)
The directory list will be added to command lines through the automatically-generated $_F77INCFLAGS construction variable, which is constructed by appending the values of the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each directory in $F77PATH. Any command lines you define that need the F77PATH directory list should include $_F77INCFLAGS:
env = Environment(F77COM="my_compiler $_F77INCFLAGS -c -o $TARGET $SOURCE")
F77PPCOM
F77PPCOMSTR
F77PPFILESUFFIXES
F90
F90COM
F90COMSTR
F90FILESUFFIXES
F90FLAGS
_F90INCFLAGS
F90PATH
env = Environment(F90PATH='#/include')
The directory look-up can also be forced using the Dir() function:
include = Dir('include')
env = Environment(F90PATH=include)
The directory list will be added to command lines through the automatically-generated $_F90INCFLAGS construction variable, which is constructed by appending the values of the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each directory in $F90PATH. Any command lines you define that need the F90PATH directory list should include $_F90INCFLAGS:
env = Environment(F90COM="my_compiler $_F90INCFLAGS -c -o $TARGET $SOURCE")
F90PPCOM
F90PPCOMSTR
F90PPFILESUFFIXES
F95
F95COM
F95COMSTR
F95FILESUFFIXES
F95FLAGS
_F95INCFLAGS
F95PATH
env = Environment(F95PATH='#/include')
The directory look-up can also be forced using the Dir() function:
include = Dir('include')
env = Environment(F95PATH=include)
The directory list will be added to command lines through the automatically-generated $_F95INCFLAGS construction variable, which is constructed by appending the values of the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each directory in $F95PATH. Any command lines you define that need the F95PATH directory list should include $_F95INCFLAGS:
env = Environment(F95COM="my_compiler $_F95INCFLAGS -c -o $TARGET $SOURCE")
F95PPCOM
F95PPCOMSTR
F95PPFILESUFFIXES
File
FILE_ENCODING
FORTRAN
FORTRANCOM
FORTRANCOMMONFLAGS
New in version 4.4.
FORTRANCOMSTR
FORTRANFILESUFFIXES
FORTRANFLAGS
_FORTRANINCFLAGS
FORTRANMODDIR
FORTRANMODDIRPREFIX
FORTRANMODDIRSUFFIX
_FORTRANMODFLAG
FORTRANMODPREFIX
FORTRANMODSUFFIX
FORTRANPATH
env = Environment(FORTRANPATH='#/include')
The directory look-up can also be forced using the Dir() function:
include = Dir('include')
env = Environment(FORTRANPATH=include)
The directory list will be added to command lines through the automatically-generated $_FORTRANINCFLAGS construction variable, which is constructed by respectively prepending and appending the values of the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each directory in $FORTRANPATH. Any command lines you define that need the FORTRANPATH directory list should include $_FORTRANINCFLAGS:
env = Environment(FORTRANCOM="my_compiler $_FORTRANINCFLAGS -c -o $TARGET $SOURCE")
FORTRANPPCOM
FORTRANPPCOMSTR
FORTRANPPFILESUFFIXES
FORTRANSUFFIXES
[".f", ".F", ".for", ".FOR", ".ftn", ".FTN", ".fpp", ".FPP", ".f77", ".F77", ".f90", ".F90", ".f95", ".F95"]
FRAMEWORKPATH
env.AppendUnique(FRAMEWORKPATH='#myframeworkdir')
will add
... -Fmyframeworkdir
to the compiler and linker command lines.
_FRAMEWORKPATH
FRAMEWORKPATHPREFIX
FRAMEWORKPREFIX
FRAMEWORKS
env.AppendUnique(FRAMEWORKS=Split('System Cocoa SystemConfiguration'))
_FRAMEWORKS
FRAMEWORKSFLAGS
GS
GSCOM
GSCOMSTR
GSFLAGS
HOST_ARCH
On the win32 platform, if the Microsoft Visual C++ compiler is available, msvc tool setup is done using $HOST_ARCH and $TARGET_ARCH. Changing the values at any later time will not cause the tool to be reinitialized. Valid host arch values are x86 and arm for 32-bit hosts and amd64 and x86_64 for 64-bit hosts.
Should be considered immutable. $HOST_ARCH is not currently used by other platforms, but the option is reserved to do so in future
HOST_OS
Should be considered immutable. $HOST_OS is not currently used by SCons, but the option is reserved to do so in future
IDLSUFFIXES
[".idl", ".IDL"]
IMPLIBNOVERSIONSYMLINKS
IMPLIBPREFIX
IMPLIBSUFFIX
IMPLIBVERSION
IMPLICIT_COMMAND_DEPENDENCIES
By default, SCons will add to each target an implicit dependency on the command represented by the first argument of any command line it executes (which is typically the command itself). By setting such a dependency, SCons can determine that a target should be rebuilt if the command changes, such as when a compiler is upgraded to a new version. The specific file for the dependency is found by searching the PATH variable in the ENV dictionary in the construction environment used to execute the command. The default is the same as setting the construction variable $IMPLICIT_COMMAND_DEPENDENCIES to a True-like value (“true”, “yes”, or “1” - but not a number greater than one, as that has a different meaning).
Action strings can be segmented by the use of an AND operator, &&. In a segemented string, each segment is a separate “command line”, these are run sequentially until one fails or the entire sequence has been executed. If an action string is segmented, then the selected behavior of $IMPLICIT_COMMAND_DEPENDENCIES is applied to each segment.
If $IMPLICIT_COMMAND_DEPENDENCIES is set to a False-like value (“none”, “false”, “no”, “0”, etc.), then the implicit dependency will not be added to the targets built with that construction environment.
If $IMPLICIT_COMMAND_DEPENDENCIES is set to “2” or higher, then that number of arguments in the command line will be scanned for relative or absolute paths. If any are present, they will be added as implicit dependencies to the targets built with that construction environment. The first argument in the command line will be searched for using the PATH variable in the ENV dictionary in the construction environment used to execute the command. The other arguments will only be found if they are absolute paths or valid paths relative to the working directory.
If $IMPLICIT_COMMAND_DEPENDENCIES is set to “all”, then all arguments in the command line will be scanned for relative or absolute paths. If any are present, they will be added as implicit dependencies to the targets built with that construction environment. The first argument in the command line will be searched for using the PATH variable in the ENV dictionary in the construction environment used to execute the command. The other arguments will only be found if they are absolute paths or valid paths relative to the working directory.
env = Environment(IMPLICIT_COMMAND_DEPENDENCIES=False)
INCPREFIX
INCSUFFIX
INSTALL
def install(dest, source, env):
dest is the path name of the destination file. source is the path name of the source file. env is the construction environment (a dictionary of construction values) in force for this file installation.
INSTALLSTR
Install file: "$SOURCE" as "$TARGET"
INTEL_C_COMPILER_VERSION
JAR
JARCHDIR
JARCOM
JARCOMSTR
env = Environment(JARCOMSTR="JARchiving $SOURCES into $TARGET")
JARFLAGS
JARSUFFIX
JAVABOOTCLASSPATH
The value will be added to the JDK command lines via the -bootclasspath option, which requires a system-specific search path separator. This will be supplied by SCons as needed when it constructs the command line if $JAVABOOTCLASSPATH is provided in list form. If $JAVABOOTCLASSPATH is a single string containing search path separator characters (: for POSIX systems or ; for Windows), it will not be modified; and so is inherently system-specific; to supply the path in a system-independent manner, give $JAVABOOTCLASSPATH as a list of paths instead.
Note
Can only be used when compiling for releases prior to JDK 9.
JAVAC
JAVACCOM
JAVACCOMSTR
env = Environment(JAVACCOMSTR="Compiling class files $TARGETS from $SOURCES")
JAVACFLAGS
JAVACLASSDIR
JAVACLASSPATH
The value will be added to the JDK command lines via the -classpath option, which requires a system-specific search path separator. This will be supplied by SCons as needed when it constructs the command line if $JAVACLASSPATH is provided in list form. If $JAVACLASSPATH is a single string containing search path separator characters (: for POSIX systems or ; for Windows), it will be split on the separator into a list of individual paths for dependency scanning purposes. It will not be modified for JDK command-line usage, so such a string is inherently system-specific; to supply the path in a system-independent manner, give $JAVACLASSPATH as a list of paths instead.
Note
SCons always supplies a -sourcepath when invoking the Java compiler javac, regardless of the setting of $JAVASOURCEPATH, as it passes the path(s) to the source(s) supplied in the call to the Java builder via -sourcepath . From the documentation of the standard Java toolkit for javac: “If not compiling code for modules, if the --source-path or -sourcepath option is not specified, then the user class path is also searched for source files.” Since -sourcepath is always supplied, javac will not use the contents of the value of $JAVACLASSPATH when searching for sources.
JAVACLASSSUFFIX
JAVAH
JAVAHCOM
JAVAHCOMSTR
env = Environment(JAVAHCOMSTR="Generating header/stub file(s) $TARGETS from $SOURCES")
JAVAHFLAGS
JAVAINCLUDES
JAVAPROCESSORPATH
The value will be added to the JDK command lines via the -processorpath option, which requires a system-specific search path separator. This will be supplied by SCons as needed when it constructs the command line if $JAVAPROCESSORPATH is provided in list form. If $JAVAPROCESSORPATH is a single string containing search path separator characters (: for POSIX systems or ; for Windows), it will not be modified; and so is inherently system-specific; to supply the path in a system-independent manner, give $JAVAPROCESSORPATH as a list of paths instead.
New in version 4.5.0
JAVASOURCEPATH
The value will be added to the JDK command lines via the -sourcepath option, which requires a system-specific search path separator, This will be supplied by SCons as needed when it constructs the command line if $JAVASOURCEPATH is provided in list form. If $JAVASOURCEPATH is a single string containing search path separator characters (: for POSIX systems or ; for Windows), it will not be modified, and so is inherently system-specific; to supply the path in a system-independent manner, give $JAVASOURCEPATH as a list of paths instead.
Note that the specified directories are only added to the command line via the -sourcepath option. SCons does not currently search the $JAVASOURCEPATH directories for dependent .java files.
JAVASUFFIX
JAVAVERSION
While this is not primarily intended for selecting one version of the Java compiler vs. another, it does have that effect on the Windows platform. A more precise approach is to set $JAVAC (and related construction variables for related utilities) to the path to the specific Java compiler you want, if that is not the default compiler. On non-Windows platforms, the alternatives system may provide a way to adjust the default Java compiler without having to specify explicit paths.
LATEX
LATEXCOM
LATEXCOMSTR
env = Environment(LATEXCOMSTR = "Building $TARGET from LaTeX input $SOURCES")
LATEXFLAGS
LATEXRETRIES
LATEXSUFFIXES
[".tex", ".ltx", ".latex"]
LDMODULE
LDMODULECOM
LDMODULECOMSTR
LDMODULEEMITTER
LDMODULEFLAGS
LDMODULENOVERSIONSYMLINKS
LDMODULEPREFIX
_LDMODULESONAME
LDMODULESUFFIX
LDMODULEVERSION
_LDMODULEVERSIONFLAGS
LDMODULEVERSIONFLAGS
LEX
LEX_HEADER_FILE
LEX_TABLES_FILE
LEXCOM
LEXCOMSTR
env = Environment(LEXCOMSTR="Lex'ing $TARGET from $SOURCES")
LEXFLAGS
Note that files specified by --header-file= and --tables-file= may not be properly handled by SCons in all situations. Consider using $LEX_HEADER_FILE and $LEX_TABLES_FILE instead.
LEXUNISTD
_LIBDIRFLAGS
LIBDIRPREFIX
LIBDIRSUFFIX
LIBEMITTER
_LIBFLAGS
LIBLINKPREFIX
LIBLINKSUFFIX
LIBPATH
Do not put library search directives directly into $LINKFLAGS or $SHLINKFLAGS as the result will be non-portable.
Note: directory names in $LIBPATH will be looked-up relative to the directory of the SConscript file when they are used in a command. To force scons to look-up a directory relative to the root of the source tree use the # prefix:
env = Environment(LIBPATH='#/libs')
The directory look-up can also be forced using the Dir function:
libs = Dir('libs')
env = Environment(LIBPATH=libs)
The directory list will be added to command lines through the automatically-generated $_LIBDIRFLAGS construction variable, which is constructed by respectively prepending and appending the values of the $LIBDIRPREFIX and $LIBDIRSUFFIX construction variables to each directory in $LIBPATH. Any command lines you define that need the $LIBPATH directory list should include $_LIBDIRFLAGS:
env = Environment(LINKCOM="my_linker $_LIBDIRFLAGS $_LIBFLAGS -o $TARGET $SOURCE")
LIBPREFIX
LIBPREFIXES
LIBS
String-valued library names should include only the library base names, without prefixes such as lib or suffixes such as .so or .dll. The library list will be added to command lines through the automatically-generated $_LIBFLAGS construction variable which is constructed by respectively prepending and appending the values of the $LIBLINKPREFIX and $LIBLINKSUFFIX construction variables to each library name in $LIBS. Library name strings should not include a path component, instead the compiler will be directed to look for libraries in the paths specified by $LIBPATH.
Any command lines you define that need the $LIBS library list should include $_LIBFLAGS:
env = Environment(LINKCOM="my_linker $_LIBDIRFLAGS $_LIBFLAGS -o $TARGET $SOURCE")
If you add a File object to the $LIBS list, the name of that file will be added to $_LIBFLAGS, and thus to the link line, as-is, without $LIBLINKPREFIX or $LIBLINKSUFFIX. For example:
env.Append(LIBS=File('/tmp/mylib.so'))
In all cases, scons will add dependencies from the executable program to all the libraries in this list.
LIBSUFFIX
LIBSUFFIXES
LICENSE
See the Package builder.
LINESEPARATOR
LINGUAS_FILE
LINK
On POSIX systems (those using the link tool), you should normally not change this value as it defaults to a "smart" linker tool which selects a compiler driver matching the type of source files in use. So for example, if you set $CXX to a specific compiler name, and are compiling C++ sources, the smartlink function will automatically select the same compiler for linking.
LINKCOM
LINKCOMSTR
env = Environment(LINKCOMSTR = "Linking $TARGET")
LINKFLAGS
M4
M4COM
M4COMSTR
M4FLAGS
MAKEINDEX
MAKEINDEXCOM
MAKEINDEXCOMSTR
MAKEINDEXFLAGS
MAXLINELENGTH
MIDL
MIDLCOM
MIDLCOMSTR
MIDLFLAGS
MOSUFFIX
MSGFMT
MSGFMTCOM
MSGFMTCOMSTR
MSGFMTFLAGS
MSGINIT
MSGINITCOM
MSGINITCOMSTR
MSGINITFLAGS
_MSGINITLOCALE
See msginit tool and POInit builder.
MSGMERGE
MSGMERGECOM
MSGMERGECOMSTR
MSGMERGEFLAGS
MSSDK_DIR
MSSDK_VERSION
MSVC_BATCH
MSVC_NOTFOUND_POLICY
The $MSVC_NOTFOUND_POLICY specifies the scons behavior when no msvc versions are detected or when the requested msvc version is not detected.
The valid values for $MSVC_NOTFOUND_POLICY and the corresponding scons behavior are:
'Error' or 'Exception'
'Warning' or 'Warn'
'Ignore' or 'Suppress'
Note: in addition to the camel case values shown above, lower case and upper case values are accepted as well.
The $MSVC_NOTFOUND_POLICY is applied when any of the following conditions are satisfied:
The $MSVC_NOTFOUND_POLICY is ignored when any of the following conditions are satisfied:
Important usage details:
When $MSVC_NOTFOUND_POLICY is not specified, the default scons behavior is to issue a warning and continue subject to the conditions listed above. The default scons behavior may change in the future.
New in version 4.4
MSVC_SCRIPT_ARGS
$MSVC_SCRIPT_ARGS is available for msvc batch file arguments that do not have first-class support via construction variables or when there is an issue with the appropriate construction variable validation. When available, it is recommended to use the appropriate construction variables (e.g., $MSVC_TOOLSET_VERSION) rather than $MSVC_SCRIPT_ARGS arguments.
The valid values for $MSVC_SCRIPT_ARGS are: None, a string, or a list of strings.
The $MSVC_SCRIPT_ARGS value is converted to a scalar string (i.e., "flattened"). The resulting scalar string, if not empty, is passed as an argument to the msvc batch file determined via autodetection subject to the validation conditions listed below.
$MSVC_SCRIPT_ARGS is ignored when the value is None and when the result from argument conversion is an empty string. The validation conditions below do not apply.
An exception is raised when any of the following conditions are satisfied:
Example 1 - A Visual Studio 2022 build with an SDK version and a toolset version specified with a string argument:
env = Environment(MSVC_VERSION='14.3', MSVC_SCRIPT_ARGS='10.0.20348.0 -vcvars_ver=14.29.30133')
Example 2 - A Visual Studio 2022 build with an SDK version and a toolset version specified with a list argument:
env = Environment(MSVC_VERSION='14.3', MSVC_SCRIPT_ARGS=['10.0.20348.0', '-vcvars_ver=14.29.30133'])
Important usage details:
New in version 4.4
MSVC_SCRIPTERROR_POLICY
The $MSVC_SCRIPTERROR_POLICY specifies the scons behavior when msvc batch file errors are detected. When $MSVC_SCRIPTERROR_POLICY is not specified, the default scons behavior is to suppress msvc batch file error messages.
The root cause of msvc build failures may be difficult to diagnose. In these situations, setting the scons behavior to issue a warning when msvc batch file errors are detected may produce additional diagnostic information.
The valid values for $MSVC_SCRIPTERROR_POLICY and the corresponding scons behavior are:
'Error' or 'Exception'
'Warning' or 'Warn'
'Ignore' or 'Suppress'
New in version 4.4
Note: in addition to the camel case values shown above, lower case and upper case values are accepted as well.
Example 1 - A Visual Studio 2022 build with user-defined script arguments:
env = environment(MSVC_VERSION='14.3', MSVC_SCRIPT_ARGS=['8.1', 'store', '-vcvars_ver=14.1'])
env.Program('hello', ['hello.c'], CCFLAGS='/MD', LIBS=['kernel32', 'user32', 'runtimeobject'])
Example 1 - Output fragment:
... link /nologo /OUT:_build001\hello.exe kernel32.lib user32.lib runtimeobject.lib _build001\hello.obj LINK : fatal error LNK1104: cannot open file 'MSVCRT.lib' ...
Example 2 - A Visual Studio 2022 build with user-defined script arguments and the script error policy set to issue a warning when msvc batch file errors are detected:
env = environment(MSVC_VERSION='14.3', MSVC_SCRIPT_ARGS=['8.1', 'store', '-vcvars_ver=14.1'], MSVC_SCRIPTERROR_POLICY='warn')
env.Program('hello', ['hello.c'], CCFLAGS='/MD', LIBS=['kernel32', 'user32', 'runtimeobject'])
Example 2 - Output fragment:
...
scons: warning: vc script errors detected:
[ERROR:vcvars.bat] The UWP Application Platform requires a Windows 10 SDK.
[ERROR:vcvars.bat] WindowsSdkDir = "C:\Program Files (x86)\Windows Kits\8.1\"
[ERROR:vcvars.bat] host/target architecture is not supported : { x64 , x64 }
...
link /nologo /OUT:_build001\hello.exe kernel32.lib user32.lib runtimeobject.lib _build001\hello.obj
LINK : fatal error LNK1104: cannot open file 'MSVCRT.lib'
Important usage details:
New in version 4.4
MSVC_SDK_VERSION
The valid values for $MSVC_SDK_VERSION are: None or a string containing the requested SDK version (e.g., '10.0.20348.0').
$MSVC_SDK_VERSION is ignored when the value is None and when the value is an empty string. The validation conditions below do not apply.
An exception is raised when any of the following conditions are satisfied:
Example 1 - A Visual Studio 2022 build with a specific Windows SDK version:
env = Environment(MSVC_VERSION='14.3', MSVC_SDK_VERSION='10.0.20348.0')
Example 2 - A Visual Studio 2022 build with a specific SDK version for the Universal Windows Platform:
env = Environment(MSVC_VERSION='14.3', MSVC_SDK_VERSION='10.0.20348.0', MSVC_UWP_APP=True)
Important usage details:
New in version 4.4
MSVC_SPECTRE_LIBS
The valid values for $MSVC_SPECTRE_LIBS are: True, False, or None.
When $MSVC_SPECTRE_LIBS is enabled (i.e., True), the Visual C++ environment will include the paths to the spectre-mitigated implementations of the Microsoft Visual C++ libraries.
An exception is raised when any of the following conditions are satisfied:
Example - A Visual Studio 2022 build with spectre mitigated Visual C++ libraries:
env = Environment(MSVC_VERSION='14.3', MSVC_SPECTRE_LIBS=True)
Important usage details:
New in version 4.4
MSVC_TOOLSET_VERSION
Specifying $MSVC_TOOLSET_VERSION does not affect the autodetection and selection of msvc instances. The $MSVC_TOOLSET_VERSION is applied after an msvc instance is selected. This could be the default version of msvc if $MSVC_VERSION is not specified.
The valid values for $MSVC_TOOLSET_VERSION are: None or a string containing the requested toolset version (e.g., '14.29').
$MSVC_TOOLSET_VERSION is ignored when the value is None and when the value is an empty string. The validation conditions below do not apply.
An exception is raised when any of the following conditions are satisfied:
Toolset selection details:
In the latest release of Visual Studio, the default Visual C++ toolset version is not necessarily the toolset with the largest version number.
Example 1 - A default Visual Studio build with a partial toolset version specified:
env = Environment(MSVC_TOOLSET_VERSION='14.2')
Example 2 - A default Visual Studio build with a partial toolset version specified:
env = Environment(MSVC_TOOLSET_VERSION='14.29')
Example 3 - A Visual Studio 2022 build with a full toolset version specified:
env = Environment(MSVC_VERSION='14.3', MSVC_TOOLSET_VERSION='14.29.30133')
Example 4 - A Visual Studio 2022 build with an SxS toolset version specified:
env = Environment(MSVC_VERSION='14.3', MSVC_TOOLSET_VERSION='14.29.16.11')
Important usage details:
New in version 4.4
MSVC_USE_SCRIPT
If set to the name of a Visual Studio .bat file (e.g. vcvars.bat), SCons will run that batch file instead of the auto-detected one, and extract the relevant variables from the result (typically %INCLUDE%, %LIB%, and %PATH%) for supplying to the build. This can be useful to force the use of a compiler version that SCons does not detect. $MSVC_USE_SCRIPT_ARGS provides arguments passed to this script.
Setting $MSVC_USE_SCRIPT to None bypasses the Visual Studio autodetection entirely; use this if you are running SCons in a Visual Studio cmd window and importing the shell's environment variables - that is, if you are sure everything is set correctly already and you don't want SCons to change anything.
$MSVC_USE_SCRIPT ignores $MSVC_VERSION and $TARGET_ARCH.
Changed in version 4.4: new $MSVC_USE_SCRIPT_ARGS provides a way to pass arguments.
MSVC_USE_SCRIPT_ARGS
New in version 4.4
MSVC_USE_SETTINGS
$MSVC_USE_SETTINGS is ignored when $MSVC_USE_SCRIPT is defined and/or when $MSVC_USE_SETTINGS is set to None.
The dictionary is used to populate the environment with the relevant variables (typically %INCLUDE%, %LIB%, and %PATH%) for supplying to the build. This can be useful to force the use of a compiler environment that SCons does not configure correctly. This is an alternative to manually configuring the environment when bypassing Visual Studio autodetection entirely by setting $MSVC_USE_SCRIPT to None.
Here is an example of configuring a build environment using the Microsoft Visual C/C++ compiler included in the Microsoft SDK on a 64-bit host and building for a 64-bit architecture:
# Microsoft SDK 6.0 (MSVC 8.0): 64-bit host and 64-bit target
msvc_use_settings = {
"PATH": [
"C:\\Program Files\\Microsoft SDKs\\Windows\\v6.0\\VC\\Bin\\x64",
"C:\\Program Files\\Microsoft SDKs\\Windows\\v6.0\\Bin\\x64",
"C:\\Program Files\\Microsoft SDKs\\Windows\\v6.0\\Bin",
"C:\\Windows\\Microsoft.NET\\Framework\\v2.0.50727",
"C:\\Windows\\system32",
"C:\\Windows",
"C:\\Windows\\System32\\Wbem",
"C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\"
],
"INCLUDE": [
"C:\\Program Files\\Microsoft SDKs\\Windows\\v6.0\\VC\\Include",
"C:\\Program Files\\Microsoft SDKs\\Windows\\v6.0\\VC\\Include\\Sys",
"C:\\Program Files\\Microsoft SDKs\\Windows\\v6.0\\Include",
"C:\\Program Files\\Microsoft SDKs\\Windows\\v6.0\\Include\\gl",
],
"LIB": [
"C:\\Program Files\\Microsoft SDKs\\Windows\\v6.0\\VC\\Lib\\x64",
"C:\\Program Files\\Microsoft SDKs\\Windows\\v6.0\\Lib\\x64",
],
"LIBPATH": [],
"VSCMD_ARG_app_plat": [],
"VCINSTALLDIR": [],
"VCToolsInstallDir": []
}
# Specifying MSVC_VERSION is recommended
env = Environment(MSVC_VERSION='8.0', MSVC_USE_SETTINGS=msvc_use_settings)
Important usage details:
New in version 4.4
MSVC_UWP_APP
The valid values for $MSVC_UWP_APP are: True, '1', False, '0', or None.
When $MSVC_UWP_APP is enabled (i.e., True or '1'), the Visual C++ environment will be set up to point to the Windows Store compatible libraries and Visual C++ runtimes. In doing so, any libraries that are built will be able to be used in a UWP App and published to the Windows Store.
An exception is raised when any of the following conditions are satisfied:
Example - A Visual Studio 2022 build for the Universal Windows Platform:
env = Environment(MSVC_VERSION='14.3', MSVC_UWP_APP=True)
Important usage details:
MSVC_VERSION
$MSVC_VERSION must be passed as an argument to the Environment constructor when an msvc tool (e.g., msvc, msvs, etc.) is loaded via the default tools list or via a tools list passed to the Environment constructor. Otherwise, $MSVC_VERSION must be set before the first msvc tool is loaded into the environment.
The valid values for $MSVC_VERSION represent major versions of the compiler, except that versions ending in Exp refer to "Express" or "Express for Desktop" Visual Studio editions, which require distict entries because they use a different filesystem layout and have some feature limitations compared to the full version. The following table shows correspondence of the selector string to various version indicators ('x' is used as a placeholder for a single digit that can vary). Note that it is not necessary to install Visual Studio to build with SCons (for example, you can install only Build Tools), but if Visual Studio is installed, additional builders such as MSVSSolution and MSVSProject become avaialable and will correspond to the indicated versions.
| SCons Key | MSVC++ Version | _MSVC_VER | VS Product | MSBuild/VS Version |
| 14.3 | 14.3x | 193x | Visual Studio 2022 | 17.x |
| 14.2 | 14.2x | 192x | Visual Studio 2019 | 16.x, 16.1x |
| 14.1 | 14.1 or 14.1x | 191x | Visual Studio 2017 | 15.x |
| 14.1Exp | 14.1 | 1910 | Visual Studio 2017 Express | 15.0 |
| 14.0 | 14.0 | 1900 | Visual Studio 2015 | 14.0 |
| 14.0Exp | 14.0 | 1900 | Visual Studio 2015 Express | 14.0 |
| 12.0 | 12.0 | 1800 | Visual Studio 2013 | 12.0 |
| 12.0Exp | 12.0 | 1800 | Visual Studio 2013 Express | 12.0 |
| 11.0 | 11.0 | 1700 | Visual Studio 2012 | 11.0 |
| 11.0Exp | 11.0 | 1700 | Visual Studio 2012 Express | 11.0 |
| 10.0 | 10.0 | 1600 | Visual Studio 2010 | 10.0 |
| 10.0Exp | 10.0 | 1600 | Visual C++ Express 2010 | 10.0 |
| 9.0 | 9.0 | 1500 | Visual Studio 2008 | 9.0 |
| 9.0Exp | 9.0 | 1500 | Visual C++ Express 2008 | 9.0 |
| 8.0 | 8.0 | 1400 | Visual Studio 2005 | 8.0 |
| 8.0Exp | 8.0 | 1400 | Visual C++ Express 2005 | 8.0 |
| 7.1 | 7.1 | 1300 | Visual Studio .NET 2003 | 7.1 |
| 7.0 | 7.0 | 1200 | Visual Studio .NET 2002 | 7.0 |
| 6.0 | 6.0 | 1100 | Visual Studio 6.0 | 6.0 |
The compilation environment can be further or more precisely specified through the use of several other construction variables: see the descriptions of $MSVC_TOOLSET_VERSION, $MSVC_SDK_VERSION, $MSVC_USE_SCRIPT, $MSVC_USE_SCRIPT_ARGS, and $MSVC_USE_SETTINGS.
MSVS
VERSION
VERSIONS
VCINSTALLDIR
VSINSTALLDIR
FRAMEWORKDIR
FRAMEWORKVERSIONS
FRAMEWORKVERSION
FRAMEWORKSDKDIR
PLATFORMSDKDIR
PLATFORMSDK_MODULES
If a value is not set, it was not available in the registry. Visual Studio 2017 and later do not use the registry for primary storage of this information, so typically for these versions only PROJECTSUFFIX and SOLUTIONSUFFIX will be set.
MSVS_ARCH
The default value is x86. amd64 is also supported by SCons for most Visual Studio versions. Since Visual Studio 2015 arm is supported, and since Visual Studio 2017 arm64 is supported. Trying to set $MSVS_ARCH to an architecture that's not supported for a given Visual Studio version will generate an error.
MSVS_PROJECT_GUID
MSVS_SCC_AUX_PATH
MSVS_SCC_CONNECTION_ROOT
MSVS_SCC_PROJECT_NAME
MSVS_SCC_PROVIDER
MSVS_VERSION
If $MSVS_VERSION is not set, SCons will (by default) select the latest version of Visual Studio installed on your system. So, if you have version 6 and version 7 (MSVS .NET) installed, it will prefer version 7. You can override this by specifying the $MSVS_VERSION variable when initializing the Environment, setting it to the appropriate version ('6.0' or '7.0', for example). If the specified version isn't installed, tool initialization will fail.
Deprecated since 1.3.0: $MSVS_VERSION is deprecated in favor of $MSVC_VERSION. As a transitional aid, if $MSVS_VERSION is set and $MSVC_VERSION is not, $MSVC_VERSION will be initialized to the value of $MSVS_VERSION. An error is raised if If both are set and have different values,
MSVSBUILDCOM
MSVSCLEANCOM
MSVSENCODING
MSVSPROJECTCOM
MSVSPROJECTSUFFIX
MSVSREBUILDCOM
MSVSSCONS
MSVSSCONSCOM
MSVSSCONSCRIPT
MSVSSCONSFLAGS
MSVSSOLUTIONCOM
MSVSSOLUTIONSUFFIX
MT
MTEXECOM
MTFLAGS
MTSHLIBCOM
MWCW_VERSION
MWCW_VERSIONS
NAME
See the Package builder.
NINJA_ALIAS_NAME
NINJA_CMD_ARGS
This value can also be passed on the command line:
scons NINJA_CMD_ARGS=-v or scons NINJA_CMD_ARGS="-v -j 3"
NINJA_COMPDB_EXPAND
Ninja's compdb tool added the -x flag in Ninja V1.9.0
NINJA_DEPFILE_PARSE_FORMAT
NINJA_DIR
NINJA_DISABLE_AUTO_RUN
If not explicitly set, this will be set to True if --disable_execute_ninja or SetOption('disable_execute_ninja', True) is seen.
NINJA_ENV_VAR_CACHE
It will be compatible with the default shell of the operating system.
If not explicitly set, SCons will generate this dynamically from the execution environment stored in the current construction environment (e.g. env['ENV']) where those values differ from the existing shell..
NINJA_FILE_NAME
NINJA_FORCE_SCONS_BUILD
NINJA_GENERATED_SOURCE_ALIAS_NAME
NINJA_GENERATED_SOURCE_SUFFIXES
NINJA_MSVC_DEPS_PREFIX
NINJA_POOL
NINJA_REGENERATE_DEPS
_NINJA_REGENERATE_DEPS_FUNC
NINJA_SCONS_DAEMON_KEEP_ALIVE
NINJA_SCONS_DAEMON_PORT
NINJA_SYNTAX
no_import_lib
OBJPREFIX
OBJSUFFIX
PACKAGEROOT
See the Package builder.
PACKAGETYPE
$PACKAGETYPE may be overridden with the --package-type command line option.
See the Package builder.
PACKAGEVERSION
See the Package builder.
PCH
env['PCH'] = File('StdAfx.pch')
PCHCOM
PCHCOMSTR
PCHPDBFLAGS
PCHSTOP
env['PCHSTOP'] = 'StdAfx.h'
PDB
env['PDB'] = 'hello.pdb'
The Visual C++ compiler switch that SCons uses by default to generate PDB information is /Z7. This works correctly with parallel (-j) builds because it embeds the debug information in the intermediate object files, as opposed to sharing a single PDB file between multiple object files. This is also the only way to get debug information embedded into a static library. Using the /Zi instead may yield improved link-time performance, although parallel builds will no longer work. You can generate PDB files with the /Zi switch by overriding the default $CCPDBFLAGS variable; see the entry for that variable for specific examples.
PDFLATEX
PDFLATEXCOM
PDFLATEXCOMSTR
env = Environment(PDFLATEX;COMSTR = "Building $TARGET from LaTeX input $SOURCES")
PDFLATEXFLAGS
PDFPREFIX
PDFSUFFIX
PDFTEX
PDFTEXCOM
PDFTEXCOMSTR
env = Environment(PDFTEXCOMSTR = "Building $TARGET from TeX input $SOURCES")
PDFTEXFLAGS
PKGCHK
PKGINFO
PLATFORM
env = Environment(tools=[]) if env['PLATFORM'] == 'cygwin':
Tool('mingw')(env) else:
Tool('msvc')(env)
POAUTOINIT
POCREATE_ALIAS
POSUFFIX
POTDOMAIN
POTSUFFIX
POTUPDATE_ALIAS
POUPDATE_ALIAS
PRINT_CMD_LINE_FUNC
The function must do the printing itself. The default implementation, used if this variable is not set or is None, is to just print the string, as in:
def print_cmd_line(s, target, source, env):
sys.stdout.write(s + "\n")
Here is an example of a more interesting function:
def print_cmd_line(s, target, source, env):
sys.stdout.write(
"Building %s -> %s...\n"
% (
' and '.join([str(x) for x in source]),
' and '.join([str(x) for x in target]),
)
) env = Environment(PRINT_CMD_LINE_FUNC=print_cmd_line) env.Program('foo', ['foo.c', 'bar.c'])
This prints:
... scons: Building targets ... Building bar.c -> bar.o... Building foo.c -> foo.o... Building foo.o and bar.o -> foo... scons: done building targets.
Another example could be a function that logs the actual commands to a file.
PROGEMITTER
PROGPREFIX
PROGSUFFIX
PSCOM
PSCOMSTR
PSPREFIX
PSSUFFIX
QT3_AUTOSCAN
Changed in 4.5.0: renamed from QT_AUTOSCAN.
QT3_BINPATH
Changed in 4.5.0: renamed from QT_BINPATH.
QT3_CPPPATH
Changed in 4.5.0: renamed from QT_CPPPATH.
QT3_DEBUG
Changed in 4.5.0: renamed from QT_DEBUG.
QT3_LIB
Changed in 4.5.0: renamed from QT_LIB.
QT3_LIBPATH
Changed in 4.5.0: renamed from QT_LIBPATH.
QT3_MOC
QT3_MOCCXXPREFIX
QT3_MOCCXXSUFFIX
Changed in 4.5.0: renamed from QT_MOCCXXSUFFIX.
QT3_MOCFROMCXXCOM
Changed in 4.5.0: renamed from QT_MOCFROMCXXCOM.
QT3_MOCFROMCXXCOMSTR
Changed in 4.5.0: renamed from QT_MOCFROMCXXCOMSTR.
QT3_MOCFROMCXXFLAGS
Changed in 4.5.0: renamed from QT_MOCFROMCXXFLAGS.
QT3_MOCFROMHCOM
Changed in 4.5.0: renamed from QT_MOCFROMSHCOM.
QT3_MOCFROMHCOMSTR
Changed in 4.5.0: renamed from QT_MOCFROMSHCOMSTR.
QT3_MOCFROMHFLAGS
Changed in 4.5.0: renamed from QT_MOCFROMSHFLAGS.
QT3_MOCHPREFIX
Changed in 4.5.0: renamed from QT_MOCHPREFIX.
QT3_MOCHSUFFIX
Changed in 4.5.0: renamed from QT_MOCHSUFFIX.
QT3_UIC
Changed in 4.5.0: renamed from QT_UIC.
QT3_UICCOM
Changed in 4.5.0: renamed from QT_UICCOM.
QT3_UICCOMSTR
Changed in 4.5.0: renamed from QT_UICCOMSTR.
QT3_UICDECLFLAGS
Changed in 4.5.0: renamed from QT_UICDECLFLAGS.
QT3_UICDECLPREFIX
Changed in 4.5.0: renamed from QT_UICDECLPREFIX.
QT3_UICDECLSUFFIX
Changed in 4.5.0: renamed from QT_UICDECLSUFFIX.
QT3_UICIMPLFLAGS
Changed in 4.5.0: renamed from QT_UICIMPFLAGS.
QT3_UICIMPLPREFIX
Changed in 4.5.0: renamed from QT_UICIMPLPREFIX.
QT3_UICIMPLSUFFIX
Changed in 4.5.0: renamed from QT_UICIMPLSUFFIX.
QT3_UISUFFIX
Changed in 4.5.0: renamed from QT_UISUFFIX.
QT3DIR
Changed in 4.5.0: renamed from QTDIR.
RANLIB
RANLIBCOM
RANLIBCOMSTR
env = Environment(RANLIBCOMSTR = "Indexing $TARGET")
RANLIBFLAGS
RC
RCCOM
RCCOMSTR
RCFLAGS
RCINCFLAGS
RCINCPREFIX
RCINCSUFFIX
RDirs
REGSVR
REGSVRCOM
REGSVRCOMSTR
REGSVRFLAGS
RMIC
RMICCOM
RMICCOMSTR
env = Environment(
RMICCOMSTR="Generating stub/skeleton class files $TARGETS from $SOURCES" )
RMICFLAGS
RPATH
_RPATH
RPATHPREFIX
RPATHSUFFIX
RPCGEN
RPCGENCLIENTFLAGS
RPCGENFLAGS
RPCGENHEADERFLAGS
RPCGENSERVICEFLAGS
RPCGENXDRFLAGS
SCANNERS
SCONS_HOME
SHCC
SHCCCOM
SHCCCOMSTR
env = Environment(SHCCCOMSTR = "Compiling shared object $TARGET")
SHCCFLAGS
SHCFLAGS
SHCXX
SHCXXCOM
SHCXXCOMSTR
env = Environment(SHCXXCOMSTR = "Compiling shared object $TARGET")
SHCXXFLAGS
SHDC
SHDCOM
SHDCOMSTR
SHDLIBVERSIONFLAGS
SHDLINK
SHDLINKCOM
SHDLINKFLAGS
SHELL
SHELL_ENV_GENERATORS
The value must be a list (or other iterable) of functions which each generate or alter the execution environment dictionary. The first function will be passed a copy of the initial execution environment ($ENV in the current construction environment); the dictionary returned by that function is passed to the next, until the iterable is exhausted and the result returned for use by the command spawner. The original execution environment is not modified.
Each function provided in $SHELL_ENV_GENERATORS must accept four arguments and return a dictionary: env is the construction environment for this action; target is the list of targets associated with this action; source is the list of sources associated with this action; and shell_env is the current dictionary after iterating any previous $SHELL_ENV_GENERATORS functions (this can be compared to the original execution environment, which is available as env['ENV'], to detect any changes).
Example:
def custom_shell_env(env, target, source, shell_env):
"""customize shell_env if desired"""
if str(target[0]) == 'special_target':
shell_env['SPECIAL_VAR'] = env.subst('SOME_VAR', target=target, source=source)
return shell_env env["SHELL_ENV_GENERATORS"] = [custom_shell_env]
Available since 4.4
SHF03
SHF03COM
SHF03COMSTR
SHF03FLAGS
SHF03PPCOM
SHF03PPCOMSTR
SHF08
SHF08COM
SHF08COMSTR
SHF08FLAGS
SHF08PPCOM
SHF08PPCOMSTR
SHF77
SHF77COM
SHF77COMSTR
SHF77FLAGS
SHF77PPCOM
SHF77PPCOMSTR
SHF90
SHF90COM
SHF90COMSTR
SHF90FLAGS
SHF90PPCOM
SHF90PPCOMSTR
SHF95
SHF95COM
SHF95COMSTR
SHF95FLAGS
SHF95PPCOM
SHF95PPCOMSTR
SHFORTRAN
SHFORTRANCOM
SHFORTRANCOMSTR
SHFORTRANFLAGS
SHFORTRANPPCOM
SHFORTRANPPCOMSTR
SHLIBEMITTER
SHLIBNOVERSIONSYMLINKS
SHLIBPREFIX
_SHLIBSONAME
SHLIBSUFFIX
SHLIBVERSION
_SHLIBVERSIONFLAGS
SHLIBVERSIONFLAGS
SHLINK
On POSIX systems (those using the link tool), you should normally not change this value as it defaults to a "smart" linker tool which selects a compiler driver matching the type of source files in use. So for example, if you set $SHCXX to a specific compiler name, and are compiling C++ sources, the smartlink function will automatically select the same compiler for linking.
SHLINKCOM
SHLINKCOMSTR
env = Environment(SHLINKCOMSTR = "Linking shared $TARGET")
SHLINKFLAGS
SHOBJPREFIX
SHOBJSUFFIX
SONAME
env.SharedLibrary('test', 'test.c', SHLIBVERSION='0.1.2', SONAME='libtest.so.2')
The variable is used, for example, by gnulink linker tool.
SOURCE
SOURCE_URL
See the Package builder.
SOURCES
SOVERSION
env.SharedLibrary('test', 'test.c', SHLIBVERSION='0.1.2', SOVERSION='2')
The variable is used, for example, by gnulink linker tool.
In the example above SONAME would be libtest.so.2 which would be a symlink and point to libtest.so.0.1.2
SPAWN
def spawn(shell, escape, cmd, args, env):
shell is a string naming the shell program to use, escape is a function that can be called to escape shell special characters in the command line, cmd is the path to the command to be executed, args holds the arguments to the command and env is a dictionary of environment variables defining the execution environment in which the command should be executed.
STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME
SUBST_DICT
SUBSTFILEPREFIX
SUBSTFILESUFFIX
SUMMARY
See the Package builder.
SWIG
SWIGCFILESUFFIX
SWIGCOM
SWIGCOMSTR
SWIGCXXFILESUFFIX
SWIGDIRECTORSUFFIX
SWIGFLAGS
_SWIGINCFLAGS
SWIGINCPREFIX
SWIGINCSUFFIX
SWIGOUTDIR
SWIGPATH
Don't explicitly put include directory arguments in $SWIGFLAGS the result will be non-portable and the directories will not be searched by the dependency scanner. Note: directory names in $SWIGPATH will be looked-up relative to the SConscript directory when they are used in a command. To force scons to look-up a directory relative to the root of the source tree use a top-relative path (#):
env = Environment(SWIGPATH='#/include')
The directory look-up can also be forced using the Dir() function:
include = Dir('include')
env = Environment(SWIGPATH=include)
The directory list will be added to command lines through the automatically-generated $_SWIGINCFLAGS construction variable, which is constructed by respectively prepending and appending the values of the $SWIGINCPREFIX and $SWIGINCSUFFIX construction variables to the beginning and end of each directory in $SWIGPATH. Any command lines you define that need the SWIGPATH directory list should include $_SWIGINCFLAGS:
env = Environment(SWIGCOM="my_swig -o $TARGET $_SWIGINCFLAGS $SOURCES")
SWIGVERSION
TAR
TARCOM
TARCOMSTR
env = Environment(TARCOMSTR = "Archiving $TARGET")
TARFLAGS
TARGET
TARGET_ARCH
On the win32 platform, if the Microsoft Visual C++ compiler is available, msvc tool setup is done using $HOST_ARCH and $TARGET_ARCH. If a value is not specified, will be set to the same value as $HOST_ARCH. Changing the value after the environment is initialized will not cause the tool to be reinitialized. Compiled objects will be in the target architecture if the compilation system supports generating for that target. The latest compiler which can fulfill the requirement will be selected, unless a different version is directed by the value of the $MSVC_VERSION construction variable.
On the win32/msvc combination, valid target arch values are x86, arm, i386 for 32-bit targets and amd64, arm64, x86_64 and ia64 (Itanium) for 64-bit targets. For example, if you want to compile 64-bit binaries, you would set TARGET_ARCH='x86_64' when creating the construction environment. Note that not all target architectures are supported for all Visual Studio / MSVC versions. Check the relevant Microsoft documentation.
$TARGET_ARCH is not currently used by other compilation tools, but the option is reserved to do so in future
TARGET_OS
$TARGET_OS is not currently used by SCons but the option is reserved to do so in future
TARGETS
TARSUFFIX
TEMPFILE
TEMPFILEARGESCFUNC
import sys import re from SCons.Subst import quote_spaces WINPATHSEP_RE = re.compile(r"\\([^\"'\\]|$)") def tempfile_arg_esc_func(arg):
arg = quote_spaces(arg)
if sys.platform != "win32":
return arg
# GCC requires double Windows slashes, let's use UNIX separator
return WINPATHSEP_RE.sub(r"/\1", arg) env["TEMPFILEARGESCFUNC"] = tempfile_arg_esc_func
TEMPFILEARGJOIN
TEMPFILEDIR
TEMPFILEPREFIX
TEMPFILESUFFIX
TEX
TEXCOM
TEXCOMSTR
env = Environment(TEXCOMSTR = "Building $TARGET from TeX input $SOURCES")
TEXFLAGS
TEXINPUTS
TEXTFILEPREFIX
TEXTFILESUFFIX
TOOLS
UNCHANGED_SOURCES
UNCHANGED_TARGETS
VENDOR
See the Package builder.
VERSION
See the Package builder.
VSWHERE
The vswhere.exe executable is distributed with Microsoft Visual Studio and Build Tools since the 2017 edition, but is also available standalone. It provides full information about installations of 2017 and later editions. With the -legacy argument, vswhere.exe can detect installations of the 2010 through 2015 editions with limited data returned. If VSWHERE is set, SCons will use that location.
Otherwise SCons will look in the following locations and set VSWHERE to the path of the first vswhere.exe located.
Note that VSWHERE must be set at the same time or prior to any of msvc, msvs , and/or mslink Tool being initialized. Either set it as follows
env = Environment(VSWHERE='c:/my/path/to/vswhere')
or if your construction environment is created specifying an empty tools list (or a list of tools which omits all of default, msvs, msvc, and mslink), and also before env.Tool is called to ininitialize any of those tools:
env = Environment(tools=[])
env['VSWHERE'] = r'c:/my/vswhere/install/location/vswhere.exe'
env.Tool('msvc')
env.Tool('mslink')
env.Tool('msvs')
WINDOWS_EMBED_MANIFEST
WINDOWS_INSERT_DEF
WINDOWS_INSERT_MANIFEST
WINDOWSDEFPREFIX
WINDOWSDEFSUFFIX
WINDOWSEXPPREFIX
WINDOWSEXPSUFFIX
WINDOWSPROGMANIFESTPREFIX
WINDOWSPROGMANIFESTSUFFIX
WINDOWSSHLIBMANIFESTPREFIX
WINDOWSSHLIBMANIFESTSUFFIX
X_IPK_DEPENDS
See the Package builder.
X_IPK_DESCRIPTION
X_IPK_MAINTAINER
X_IPK_PRIORITY
X_IPK_SECTION
X_MSI_LANGUAGE
See the Package builder.
X_MSI_LICENSE_TEXT
See the Package builder.
X_MSI_UPGRADE_CODE
X_RPM_AUTOREQPROV
See the Package builder.
X_RPM_BUILD
X_RPM_BUILDREQUIRES
X_RPM_BUILDROOT
X_RPM_CLEAN
X_RPM_CONFLICTS
X_RPM_DEFATTR
X_RPM_DISTRIBUTION
X_RPM_EPOCH
X_RPM_EXCLUDEARCH
X_RPM_EXLUSIVEARCH
X_RPM_EXTRADEFS
env.Package(
NAME="foo",
...
X_RPM_EXTRADEFS=[
"%define _unpackaged_files_terminate_build 0"
"%define _missing_doc_files_terminate_build 0"
],
... )
X_RPM_GROUP
X_RPM_GROUP_lang
X_RPM_ICON
X_RPM_INSTALL
X_RPM_PACKAGER
X_RPM_POSTINSTALL
X_RPM_POSTUNINSTALL
X_RPM_PREFIX
X_RPM_PREINSTALL
X_RPM_PREP
X_RPM_PREUNINSTALL
X_RPM_PROVIDES
X_RPM_REQUIRES
X_RPM_SERIAL
X_RPM_URL
XGETTEXT
XGETTEXTCOM
XGETTEXTCOMSTR
_XGETTEXTDOMAIN
XGETTEXTFLAGS
XGETTEXTFROM
_XGETTEXTFROMFLAGS
XGETTEXTFROMPREFIX
XGETTEXTFROMSUFFIX
XGETTEXTPATH
Note
This variable works only together with $XGETTEXTFROM
_XGETTEXTPATHFLAGS
XGETTEXTPATHPREFIX
XGETTEXTPATHSUFFIX
YACC
YACC_GRAPH_FILE
YACC_HEADER_FILE
YACCCOM
YACCCOMSTR
env = Environment(YACCCOMSTR="Yacc'ing $TARGET from $SOURCES")
YACCFLAGS
If a -d option is present, scons assumes that the call will also create a header file with the suffix defined by $YACCHFILESUFFIX if the yacc source file ends in a .y suffix, or a file with the suffix defined by $YACCHXXFILESUFFIX if the yacc source file ends in a .yy suffix.
If a -g option is present, scons assumes that the call will also create a graph file with the suffix defined by $YACCVCGFILESUFFIX.
If a -v option is present, scons assumes that the call will also create an output debug file with the suffix .output.
Also recognized are GNU bison options --header= and its deprecated synonym --defines=, which is similar to -d but the output filename is named by the option argument; and --graph=, which is similar to -g but the output filename is named by the option argument.
Note that files specified by --header= and --graph= may not be properly handled by SCons in all situations. Consider using $YACC_HEADER_FILE and $YACC_GRAPH_FILE instead.
YACCHFILESUFFIX
YACCHXXFILESUFFIX
YACCVCGFILESUFFIX
ZIP
ZIP_OVERRIDE_TIMESTAMP
ZIPCOM
ZIPCOMPRESSION
ZIPCOMSTR
env = Environment(ZIPCOMSTR = "Zipping $TARGET")
ZIPFLAGS
ZIPROOT
env = Environment()
env.Zip('foo.zip', 'subdir1/subdir2/file1', ZIPROOT='subdir1')
will produce a zip file foo.zip containing a file with the name subdir2/file1 rather than subdir1/subdir2/file1.
ZIPSUFFIX
Configure Contexts¶
SCons supports a configure context, an integrated mechanism similar to the various AC_CHECK macros in GNU Autoconf for testing the existence of external items needed for the build, such as C header files, libraries, etc. The mechanism is portable across platforms.
scons does not maintain an explicit cache of the tested values (this is different than Autoconf), but uses its normal dependency tracking to keep the checked values up to date. However, users may override this behaviour with the --config command line option.
Configure(env, [custom_tests, conf_dir, log_file, config_h, clean, help]), env.Configure([custom_tests, conf_dir, log_file, config_h, clean, help])
Changed in version 4.0: raises an exception on an attempt to create a new context when there is an active context.
custom_tests specifies a dictionary containing custom tests (see the section on custom tests below). The default value is None, meaning no custom tests are added to the configure context.
conf_dir specifies a directory where the test cases are built. This directory is not used for building normal targets. The default value is “#/.sconf_temp”.
log_file specifies a file which collects the output from commands that are executed to check for the existence of header files, libraries, etc. The default is “#/config.log”. If you are using variant directories, you may want to place the log file for a given build under that build's variant directory.
config_h specifies a C header file where the results of tests will be written. The results will consist of lines like #define HAVE_STDIO_H, #define HAVE_LIBM, etc. Customarily, the name chosen is “config.h”. The default is to not write a config_h file. You can specify the same config_h file in multiple calls to Configure, in which case SCons will concatenate all results in the specified file. Note that SCons uses its normal dependency checking to decide if it's necessary to rebuild the specified config_h file. This means that the file is not necessarily re-built each time scons is run, but is only rebuilt if its contents will have changed and some target that depends on the config_h file is being built.
The clean and help arguments can be used to suppress execution of the configuration tests when the -c/--clean or -H/-h/--help options are used, respectively. The default behavior is always to execute configure context tests, since the results of the tests may affect the list of targets to be cleaned or the help text. If the configure tests do not affect these, then you may add the clean=False or help=False arguments (or both) to avoid unnecessary test execution.
context.Finish()
Example of a typical Configure usage:
env = Environment()
conf = Configure(env)
if not conf.CheckCHeader("math.h"):
print("We really need math.h!")
Exit(1)
if conf.CheckLibWithHeader("qt", "qapp.h", "c++", "QApplication qapp(0,0);"):
# do stuff for qt - usage, e.g.
conf.env.Append(CPPDEFINES="WITH_QT")
env = conf.Finish()
A configure context has the following predefined methods which can be used to perform checks. Where language is an optional parameter, it specifies the compiler to use for the check, currently a choice of C or C++. The spellings accepted for C are “C” or “c”; for C++ the value can be “CXX”, “cxx”, “C++” or “c++”. If language is omitted, “C” is assumed.
context.CheckHeader(header, [include_quotes, language])
Returns a boolean indicating success or failure.
context.CheckCHeader(header, [include_quotes])
context.CheckCXXHeader(header, [include_quotes])
context.CheckFunc(function_name, [header, language])
The optional header argument is a string representing a code fragment to place at the top of the test program that will be compiled to check if the function exists. If omitted, the default stanza will be (with function_name appropriately substituted):
#ifdef __cplusplus extern "C" #endif char function_name(void);
Note: if header is supplied, it should not include the standard header file that declares function_name, and it should include a dummy prototype similar to the default case. Compilers reject builds where a function call does not match the declared prototype as happens if the "real" header is included, and modern compilers are now rejecting implicit function declarations.
Returns a boolean indicating success or failure.
context.CheckLib([library, symbol, header, language, autoadd=True, append=True, unique=False])
library can be a list of library names, or None (the default if the argument is omitted). If the former, symbol is checked against each library name in order, returning (and reporting success) on the first successful test; if the latter, it is checked with the current value of $LIBS (in this case no library name would be added). If symbol is omitted or None, then CheckLib just checks if you can link against the specified library, Note though it is legal syntax, it would not be very useful to call this method with library and symbol both omitted or None - at least one should be supplied.
Returns a boolean indicating success or failure.
Changed in version 4.5.0: added the append and unique parameters.
context.CheckLibWithHeader(library, header, [language, call, autoadd=True, append=True, unique=False])
Returns a boolean indicating success or failure.
Changed in version 4.5.0: added the append and unique parameters.
context.CheckType(type_name, [includes, language])
sconf.CheckType('foo_type', '#include "my_types.h"', 'C++')
Returns a boolean indicating success or failure.
context.CheckTypeSize(type_name, [header, language, expect])
For example,
CheckTypeSize('short', expect=2)
will return the size 2 only if short is actually two bytes.
context.CheckCC()
The test program will be built with the same command line as the one used by the Object builder for C source files, so by setting relevant construction variables it can be used to detect if particular compiler flags will be accepted or rejected by the compiler.
Returns a boolean indicating success or failure.
context.CheckCXX()
The test program will be built with the same command line as the one used by the Object builder for C++ source files, so by setting relevant construction variables it can be used to detect if particular compiler flags will be accepted or rejected by the compiler.
Returns a boolean indicating success or failure.
context.CheckSHCC()
The test program will be built with the same command line as the one used by the SharedObject builder for C source files, so by setting relevant construction variables it can be used to detect if particular compiler flags will be accepted or rejected by the compiler. Note this does not check whether a shared library/dll can be created.
Returns a boolean indicating success or failure.
context.CheckSHCXX()
The test program will be built with the same command line as the one used by the SharedObject builder for C++ source files, so by setting relevant construction variables it can be used to detect if particular compiler flags will be accepted or rejected by the compiler. Note this does not check whether a shared library/dll can be created.
Returns a boolean indicating success or failure.
context.CheckProg(prog_name)
context.CheckDeclaration(symbol, [includes, language])
Returns a boolean indicating success or failure.
context.CheckMember(aggregate_member, [header, language])
sconf.CheckMember('struct tm.tm_sec', '#include <time.h>')
Returns a boolean indicating success or failure.
context.Define(symbol, [value, comment])
Examples:
env = Environment()
conf = Configure(env)
# Puts the following line in the config header file:
# #define A_SYMBOL
conf.Define("A_SYMBOL")
# Puts the following line in the config header file:
# #define A_SYMBOL 1
conf.Define("A_SYMBOL", 1)
Examples of quoting string values:
env = Environment()
conf = Configure(env)
# Puts the following line in the config header file:
# #define A_SYMBOL YA
conf.Define("A_SYMBOL", "YA")
# Puts the following line in the config header file:
# #define A_SYMBOL "YA"
conf.Define("A_SYMBOL", '"YA"')
Example including comment:
env = Environment()
conf = Configure(env)
# Puts the following lines in the config header file:
# /* Set to 1 if you have a symbol */
# #define A_SYMBOL 1
conf.Define("A_SYMBOL", 1, "Set to 1 if you have a symbol")
You can define your own custom checks in addition to using the predefined checks. To enable custom checks, pass a dictionary to the Configure function as the custom_tests parameter. The dictionary maps the names of the checks to the custom check callables (either a Python function or an instance of a class implementing a __call__ method). Each custom check will be called with a a CheckContext instance as the first parameter followed by the remaining arguments, which must be supplied by the user of the check. A CheckContext is not the same as a configure context; rather it is an instance of a class which contains a configure context (available as chk_ctx.sconf). A CheckContext provides the following methods which custom checks can make use of::
chk_ctx.Message(text)
chk_ctx.Result(res)
chk_ctx.TryCompile(text, extension='')
chk_ctx.TryLink(text, extension='')
chk_ctx.TryRun(text, extension='')
chk_ctx.TryAction(action, [text, extension=''])
chk_ctx.TryBuild(builder, [text, extension=''])
Example of implementing and using custom tests:
def CheckQt(chk_ctx, qtdir):
chk_ctx.Message('Checking for qt ...')
lastLIBS = chk_ctx.env['LIBS']
lastLIBPATH = chk_ctx.env['LIBPATH']
lastCPPPATH = chk_ctx.env['CPPPATH']
chk_ctx.env.Append(LIBS='qt', LIBPATH=qtdir + '/lib', CPPPATH=qtdir + '/include')
ret = chk_ctx.TryLink(
"""\ #include <qapp.h> int main(int argc, char **argv) {
QApplication qapp(argc, argv);
return 0; } """
)
if not ret:
chkctx.env.Replace(LIBS=lastLIBS, LIBPATH=lastLIBPATH, CPPPATH=lastCPPPATH)
chkctx.Result(ret)
return ret env = Environment() conf = Configure(env, custom_tests={'CheckQt': CheckQt}) if not conf.CheckQt('/usr/lib/qt'):
print('We really need qt!')
Exit(1) env = conf.Finish()
Command-Line Construction Variables¶
Often when building software, some variables need to be specified at build time. For example, libraries needed for the build may be in non-standard locations, or site-specific compiler options may need to be passed to the compiler. SCons provides a Variables object to support overriding construction variables with values obtained from various sources, often from the command line:
scons VARIABLE=foo
The variable values can also be specified in a configuration file or an SConscript file.
To obtain the object for manipulating values, call the Variables function:
Variables([files, [args]])
The following example file contents could be used to set an alternative C compiler:
CC = 'my_cc'
If args is specified, it is a dictionary of values that will override anything read from files. The primary use is to pass the ARGUMENTS dictionary that holds variables specified on the command line, allowing you to indicate that if a setting appears on both the command line and in the file(s), the command line setting takes precedence. However, any dictionary can be passed. Examples:
vars = Variables('custom.py')
vars = Variables('overrides.py', ARGUMENTS)
vars = Variables(None, {FOO:'expansion', BAR:7})
Calling Variables with no arguments is equivalent to:
vars = Variables(files=None, args=ARGUMENTS)
Note that since the variables are eventually added as construction variables, you should choose variable names which do not unintentionally change pre-defined construction variables that your project will make use of (see the section called “Construction Variables”).
Variables objects have the following methods:
vars.Add(key, [help, default, validator, converter])
As a special case, if key is a tuple (or list) and is the only argument, the tuple is unpacked into the five parameters listed above left to right, with any missing members filled with the respecitive default values. This form allows Add to consume a tuple emitted by the convenience functions BoolVariable, EnumVariable, ListVariable, PackageVariable and PathVariable.
If the optional validator is supplied, it is called to validate the value of the variable. A function supplied as a validator must accept three arguments: key, value and env, and should raise an exception with a helpful error message if value is invalid. No return value is expected from the validator.
If the optional converter is supplied, it is called to convert the value before putting it in the environment, and should take either a value or a value and environment as parameters. The converter function must return a value, which will be converted into a string and be passed to the validator (if any) and then added to the construction environment.
Examples:
vars.Add('CC', help='The C compiler')
def valid_color(key, val, env):
if not val in ['red', 'blue', 'yellow']:
raise Exception("Invalid color value '%s'" % val)
vars.Add('COLOR', validator=valid_color)
vars.AddVariables(args)
opt.AddVariables(
("debug", "", 0),
("CC", "The C compiler"),
("VALIDATE", "An option for testing validation", "notset", validator, None), )
vars.Update(env, [args])
Normally this method is not called directly, but rather invoked indirectly by passing the Variables object to the Environment function:
env = Environment(variables=vars)
vars.UnknownVariables()
env = Environment(variables=vars) for key, value in vars.UnknownVariables():
print("unknown variable: %s=%s" % (key, value))
vars.Save(filename, env)
env = Environment()
vars = Variables(['variables.cache', 'custom.py'])
vars.Add(...)
vars.Update(env)
vars.Save('variables.cache', env)
vars.GenerateHelpText(env, [sort])
Help(vars.GenerateHelpText(env)) def cmp(a, b):
return (a > b) - (a < b) Help(vars.GenerateHelpText(env, sort=cmp))
vars.FormatVariableHelpText(env, opt, help, default, actual)
def my_format(env, opt, help, default, actual):
fmt = "\n%s: default=%s actual=%s (%s)\n"
return fmt % (opt, default, actual, help) vars.FormatVariableHelpText = my_format
To make it more convenient to work with customizable Variables, scons provides a number of functions that make it easy to set up various types of Variables. Each of these return a tuple ready to be passed to the Add or AddVariables method:
BoolVariable(key, help, default)
EnumVariable(key, help, default, allowed_values, [map, ignorecase])
ListVariable(key, help, default, names, [map])
PackageVariable(key, help, default)
PathVariable(key, help, default, [validator])
PathVariable.PathExists
PathVariable.PathIsFile
PathVariable.PathIsDir
PathVariable.PathIsDirCreate
PathVariable.PathAccept
You may supply your own validator function, which must accept three arguments (key, the name of the variable to be set; val, the specified value being checked; and env, the construction environment) and should raise an exception if the specified value is not acceptable.
These functions make it convenient to create a number of variables with consistent behavior in a single call to the AddVariables method:
vars.AddVariables(
BoolVariable(
"warnings",
help="compilation with -Wall and similar",
default=True,
),
EnumVariable(
"debug",
help="debug output and symbols",
default="no",
allowed_values=("yes", "no", "full"),
map={},
ignorecase=0, # case sensitive
),
ListVariable(
"shared",
help="libraries to build as shared libraries",
default="all",
names=list_of_libs,
),
PackageVariable(
"x11",
help="use X11 installed here (yes = search some places)",
default="yes",
),
PathVariable(
"qtdir",
help="where the root of Qt is installed",
default=qtdir),
PathVariable(
"foopath",
help="where the foo library is installed",
default=foopath,
validator=PathVariable.PathIsDir,
), )
Node Objects¶
SCons represents objects that are the sources or targets of build operations as Nodes, which are internal data structures. There are a number of user-visible types of nodes: File Nodes, Directory Nodes, Value Nodes and Alias Nodes. Some of the node types have public attributes and methods, described below. Each of the node types has a global function and a matching environment method to create instances: File, Dir, Value and Alias.
Filesystem Nodes
The File and Dir functions/methods return File and Directory Nodes, respectively. File and Directory Nodes (collectively, Filesystem Nodes) represent build components that correspond to an entry in the computer's filesystem, whether or not such an entry exists at the time the Node is created. You do not usually need to explicitly create filesystem Nodes, since when you supply a string as a target or source of a Builder, SCons will create the Nodes as needed to populate the dependency graph. Builders return the target Node(s) in the form of a list, which you can then make use of. However, since filesystem Nodes have some useful public attributes and methods that you can use in SConscript files, it is sometimes appropriate to create them manually, outside the regular context of a Builder call.
The following attributes provide information about a Node:
node.path
node.abspath
node.relpath
node.srcnode()
Examples:
# Get the current build dir's path, relative to top.
Dir('.').path
# Current dir's absolute path
Dir('.').abspath
# Current dir's path relative to the root SConstruct file's directory
Dir('.').relpath
# Next line is always '.', because it is the top dir's path relative to itself.
Dir('#.').path
# Source path of the given source file.
File('foo.c').srcnode().path
# Builders return lists of File objects:
foo = env.Program('foo.c')
print("foo will be built in", foo[0].path)
Filesystem Node objects have methods to create new File and Directory Nodes relative to the original Node. There are also times when you may need to refer to an entry in a filesystem without knowing in advance whether it's a file or a directory. For those situations, there is an Entry method of filesystem node objects, which returns a Node that can represent either a file or a directory.
If the original Node is a Directory Node, these methods will place the new Node within the directory the original Node represents:
node.Dir(name)
node.File(name)
node.Entry(name)
If the original Node is a File Node, these methods will place the the new Node in the same directory as the one the original Node represents:
node.Dir(name)
node.File(name)
node.Entry(name)
For example:
# Get a Node for a file within a directory
incl = Dir('include')
f = incl.File('header.h')
# Get a Node for a subdirectory within a directory
dist = Dir('project-3.2.1')
src = dist.Dir('src')
# Get a Node for a file in the same directory
cfile = File('sample.c')
hfile = cfile.File('sample.h')
# Combined example
docs = Dir('docs')
html = docs.Dir('html')
index = html.File('index.html')
css = index.File('app.css')
Value and Alias Nodes
SCons provides two other Node types to represent object that will not have an equivalent filesystem entry. Such Nodes always need to be created explicitly.
The Alias method returns an Alias Node. Aliases are virtual objects - they will not themselves result in physical objects being constructed, but are entered into the dependency graph related to their sources. An alias is checked for up to date by checking if its sources are up to date. An alias is built by making sure its sources have been built, and if any building took place, applying any Actions that are defined as part of the alias.
An Alias call creates an entry in the alias namespace, which is used for disambiguation. If an alias source has a string valued name, it will be resolved to a filesystem entry Node, unless it is found in the alias namespace, in which case it it resolved to the matching alias Node. As a result, the order of Alias calls is significant. An alias can refer to another alias, but only if the other alias has previously been created.
The Value method returns a Value Node. Value nodes are often used for generated data that will not have any corresponding filesystem entry, but will be used to determine whether a build target is out of date, or to include as part of a build Action. Common examples are timestamp strings, revision control version strings and other run-time generated strings.
A Value Node can also be the target of a builder.
EXTENDING SCONS¶
SCons is designed to be extensible through provided facilities, so changing the code of SCons itself is only rarely needed to customize its behavior. A number of the main operations use callable objects which can be supplemented by writing your own. Builders, Scanners and Tools each use a kind of plugin system, allowing you to easily drop in new ones. Information about creating Builder Objects and Scanner Objects appear in the following sections. The instructions SCons actually uses to construct things are called Actions, and it is easy to create Action Objects and hand them to the objects that need to know about those actions (besides Builders, see AddPostAction, AddPreAction and Alias for some examples of other places that take Actions). Action Objects are also described below. Adding new Tool modules is described in Tool Modules
Builder Objects¶
scons can be extended to build different types of targets by adding new Builder objects to a construction environment. In general, you should only need to add a new Builder object when you want to build a new type of file or other external target. For output file types scons already knows about, you can usually modify the behavior of premade Builders such as Program, Object or Library by changing the construction variables they use ($CC, $LINK, etc.). In this manner you can, for example, change the compiler to use, which is simpler and less error-prone than writing a new builder. The documentation for each Builder lists which construction variables it uses.
Builder objects are created using the Builder factory function. Once created, a builder is added to an environment by entering it in the $BUILDERS dictionary in that environment (some of the examples in this section illustrate this). Doing so automatically triggers SCons to add a method with the name of the builder to the environment.
The Builder function accepts the following keyword arguments:
action
An action function must accept three arguments: source, target and env. source is a list of source nodes; target is a list of target nodes; env is the construction environment to use for context.
The action and generator arguments must not both be used for the same Builder.
prefix
b = Builder("build_it < $SOURCE > $TARGET",
prefix="file-")
def gen_prefix(env, sources):
return "file-" + env['PLATFORM'] + '-'
b = Builder("build_it < $SOURCE > $TARGET",
prefix=gen_prefix)
b = Builder("build_it < $SOURCE > $TARGET",
suffix={None: "file-", "$SRC_SFX_A": gen_prefix})
suffix
b = Builder("build_it < $SOURCE > $TARGET"
suffix="-file")
def gen_suffix(env, sources):
return "." + env['PLATFORM'] + "-file"
b = Builder("build_it < $SOURCE > $TARGET",
suffix=gen_suffix)
b = Builder("build_it < $SOURCE > $TARGET",
suffix={None: ".sfx1", "$SRC_SFX_A": gen_suffix})
ensure_suffix
b1 = Builder("build_it < $SOURCE > $TARGET"
suffix = ".out")
b2 = Builder("build_it < $SOURCE > $TARGET"
suffix = ".out",
ensure_suffix=True)
env = Environment()
env['BUILDERS']['B1'] = b1
env['BUILDERS']['B2'] = b2
# Builds "foo.txt" because ensure_suffix is not set.
env.B1('foo.txt', 'foo.in')
# Builds "bar.txt.out" because ensure_suffix is set.
env.B2('bar.txt', 'bar.in')
src_suffix
target_scanner
source_scanner
target_factory
Example:
MakeDirectoryBuilder = Builder(action=my_mkdir, target_factory=Dir)
env = Environment()
env.Append(BUILDERS={'MakeDirectory': MakeDirectoryBuilder})
env.MakeDirectory('new_directory', [])
Note that the call to this MakeDirectory Builder needs to specify an empty source list to make the string represent the builder's target; without that, it would assume the argument is the source, and would try to deduce the target name from it, which in the absence of an automatically-added prefix or suffix would lead to a matching target and source name and a circular dependency.
source_factory
Example:
CollectBuilder = Builder(action=my_mkdir, source_factory=Entry)
env = Environment()
env.Append(BUILDERS={'Collect': CollectBuilder})
env.Collect('archive', ['directory_name', 'file_name'])
emitter
A function passed as emitter must accept three arguments: source, target and env. source is a list of source nodes, target is a list of target nodes, env is the construction environment to use for context.
An emitter must return a tuple containing two lists, the list of targets to be built by this builder, and the list of sources for this builder.
Example:
def e(target, source, env):
return target + ['foo.foo'], source + ['foo.src'] # Simple association of an emitter function with a Builder. b = Builder("my_build < $TARGET > $SOURCE", emitter=e) def e2(target, source, env):
return target + ['bar.foo'], source + ['bar.src'] # Simple association of a list of emitter functions with a Builder. b = Builder("my_build < $TARGET > $SOURCE", emitter=[e, e2]) # Calling an emitter function through a construction variable. env = Environment(MY_EMITTER=e) b = Builder("my_build < $TARGET > $SOURCE", emitter='$MY_EMITTER') # Calling a list of emitter functions through a construction variable. env = Environment(EMITTER_LIST=[e, e2]) b = Builder("my_build < $TARGET > $SOURCE", emitter='$EMITTER_LIST') # Associating multiple emitters with different file # suffixes using a dictionary. def e_suf1(target, source, env):
return target + ['another_target_file'], source def e_suf2(target, source, env):
return target, source + ['another_source_file'] b = Builder(
action="my_build < $TARGET > $SOURCE",
emitter={'.suf1': e_suf1, '.suf2': e_suf2} )
multi
env
generator
A function passed as generator must accept four arguments: source, target, env and for_signature. source is a list of source nodes, target is a list of target nodes, env is the construction environment to use for context, and for_signature is a Boolean value that tells the function if it is being called for the purpose of generating a build signature (as opposed to actually executing the command). Since the build signature is used for rebuild determination, the function should omit those elements that do not affect whether a rebuild should be triggered if for_signature is true.
Example:
def g(source, target, env, for_signature):
return [["gcc", "-c", "-o"] + target + source] b = Builder(generator=g)
The generator and action arguments must not both be used for the same Builder.
src_builder
single_source
source_ext_match
In the following example, the setting of source_ext_match prevents scons from exiting with an error due to the mismatched suffixes of foo.in and foo.extra.
b = Builder(action={'.in' : 'build $SOURCES > $TARGET'},
source_ext_match=False)
env = Environment(BUILDERS={'MyBuild':b})
env.MyBuild('foo.out', ['foo.in', 'foo.extra'])
env
b = Builder(action="build < $SOURCE > $TARGET")
env = Environment(BUILDERS={'MyBuild' : b})
env.MyBuild('foo.out', 'foo.in', my_arg='xyzzy')
chdir
Note that scons will not automatically modify its expansion of construction variables like $TARGET and $SOURCE when using the chdir keyword argument--that is, the expanded file names will still be relative to the top-level directory containing the SConstruct file, and consequently incorrect relative to the chdir directory. Builders created using chdir keyword argument, will need to use construction variable expansions like ${TARGET.file} and ${SOURCE.file} to use just the filename portion of the targets and source.
b = Builder(action="build < ${SOURCE.file} > ${TARGET.file}",
chdir=1)
env = Environment(BUILDERS={'MyBuild' : b})
env.MyBuild('sub/dir/foo.out', 'sub/dir/foo.in')
Warning
Python only keeps one current directory location even if there are multiple threads. This means that use of the chdir argument will not work with the SCons -j option, because individual worker threads spawned by SCons interfere with each other when they start changing directory.
Any additional keyword arguments supplied when a Builder object is created (that is, when the Builder function is called) will be set in the executing construction environment when the Builder object is called. The canonical example here would be to set a construction variable to the repository of a source code system.
Any such keyword arguments supplied when a Builder object is called will only be associated with the target created by that particular Builder call (and any other files built as a result of the call). These extra keyword arguments are passed to the following functions: command generator functions, function Actions, and emitter functions.
Action Objects¶
The Builder factory function will turn its action keyword argument into an appropriate internal Action object, as will the Command function. You can also explicitly create Action objects for passing to Builder, or other functions that take actions as arguments, by calling the Action factory function. This may more efficient when multiple Builder objects need to do the same thing rather than letting each of those Builder objects create a separate Action object. It also allows more flexible configuration of an Action object. For example, to control the message printed when the action is taken you need to create the action object using Action.
The Action factory function returns an appropriate object for the action represented by the type of the action argument (the first positional parameter):
Action('$CC -c -o $TARGET $SOURCES')
# Doesn't print the line being executed.
Action('@build $TARGET $SOURCES')
# Ignores return value
Action('-build $TARGET $SOURCES')
Action([['cc', '-c', '-DWHITE SPACE', '-o', '$TARGET', '$SOURCES']])
The target and source arguments may be lists of Node objects if there is more than one target file or source file. The actual target and source file name(s) may be retrieved from their Node objects via the built-in Python str function:
target_file_name = str(target) source_file_names = [str(x) for x in source]
The function should return 0 or None to indicate a successful build of the target file(s). The function may raise an exception or return a non-zero exit status to indicate an unsuccessful build.
def build_it(target=None, source=None, env=None):
# build the target from the source
return 0 a = Action(build_it)
The environment method form env.Action will expand construction variables in any argument strings, including action, at the time it is called, using the construction variables in the construction environment through which it was called. The global function form Action delays variable expansion until the Action object is actually used.
The optional second argument to Action is used to control the output which is printed when the Action is actually performed. If this parameter is omitted, or if the value is an empty string, a default output depending on the type of the action is used. For example, a command-line action will print the executed command. The following argument types are accepted:
The cmdstr and strfunction keyword arguments may not both be supplied in a single call to Action
Printing of action strings is affected by the setting of $PRINT_CMD_LINE_FUNC.
Examples:
def build_it(target, source, env):
# build the target from the source
return 0 def string_it(target, source, env):
return "building '%s' from '%s'" % (target[0], source[0]) # Use a positional argument. f = Action(build_it, string_it) s = Action(build_it, "building '$TARGET' from '$SOURCE'") # Alternatively, use a keyword argument. f = Action(build_it, strfunction=string_it) s = Action(build_it, cmdstr="building '$TARGET' from '$SOURCE'") # You can provide a configurable variable. l = Action(build_it, '$STRINGIT')
Any additional positional arguments, if present, may either be construction variables or lists of construction variables whose values will be included in the signature of the Action (the build signature) when deciding whether a target should be rebuilt because the action changed. Such variables may also be specified using the varlist keyword parameter; both positional and keyword forms may be present, and will be combined. This is necessary whenever you want a target to be rebuilt when a specific construction variable changes. This is not often needed for a string action, as the expanded variables will normally be part of the command line, but may be needed if a Python function action uses the value of a construction variable when generating the command line.
def build_it(target, source, env):
# build the target from the 'XXX' construction variable
with open(target[0], 'w') as f:
f.write(env['XXX'])
return 0 # Use positional arguments. a = Action(build_it, '$STRINGIT', ['XXX']) # Alternatively, use a keyword argument. a = Action(build_it, varlist=['XXX'])
The Action factory function can be passed the following optional keyword arguments to modify the Action object's behavior:
chdir
Note that SCons will not automatically modify its expansion of construction variables like $TARGET and $SOURCE when using the chdir parameter - that is, the expanded file names will still be relative to the top-level directory containing the SConstruct file, and consequently incorrect relative to the chdir directory. Builders created using chdir keyword argument, will need to use construction variable expansions like ${TARGET.file} and ${SOURCE.file} to use just the filename portion of the targets and source. Example:
a = Action("build < ${SOURCE.file} > ${TARGET.file}", chdir=True)
exitstatfunc
def always_succeed(s):
# Always return 0, which indicates success.
return 0 a = Action("build < ${SOURCE.file} > ${TARGET.file}",
exitstatfunc=always_succeed)
batch_key
a = Action('build $CHANGED_SOURCES', batch_key=True)
The batch_key argument may also be a callable function that returns a key that will be used to identify different "batches" of target files to be collected for batch building. A batch_key function must accept four parameters: action, env, target and source. The first parameter, action, is the active action object. The second parameter, env, is the construction environment configured for the target. The target and source parameters are the lists of targets and sources for the configured action.
The returned key should typically be a tuple of values derived from the arguments, using any appropriate logic to decide how multiple invocations should be batched. For example, a batch_key function may decide to return the value of a specific construction variable from env which will cause scons to batch-build targets with matching values of that construction variable, or perhaps return the Python id() of the entire construction environment, in which case scons will batch-build all targets configured with the same construction environment. Returning None indicates that the particular target should not be part of any batched build, but instead will be built by a separate invocation of action's command or function. Example:
def batch_key(action, env, target, source):
tdir = target[0].dir
if tdir.name == 'special':
# Don't batch-build any target
# in the special/ subdirectory.
return None
return (id(action), id(env), tdir) a = Action('build $CHANGED_SOURCES', batch_key=batch_key)
Miscellaneous Action Functions
SCons supplies Action functions that arrange for various common file and directory manipulations to be performed. These are similar in concept to "tasks" in the Ant build tool, although the implementation is slightly different. These functions do not actually perform the specified action at the time the function is called, but rather are factory functions which return an Action object that can be executed at the appropriate time.
There are two natural ways that these Action Functions are intended to be used.
First, if you need to perform the action at the time the SConscript file is being read, you can use the Execute global function:
Execute(Touch('file'))
Second, you can use these functions to supply Actions in a list for use by the env.Command method. This can allow you to perform more complicated sequences of file manipulation without relying on platform-specific external commands:
env = Environment(TMPBUILD='/tmp/builddir') env.Command(
target='foo.out',
source='foo.in',
action=[
Mkdir('$TMPBUILD'),
Copy('$TMPBUILD', '${SOURCE.dir}'),
"cd $TMPBUILD && make",
Delete('$TMPBUILD'),
], )
Chmod(dest, mode)
Execute(Chmod('file', 0o755))
env.Command(
'foo.out',
'foo.in',
[Copy('$TARGET', '$SOURCE'), Chmod('$TARGET', 0o755)],
)
Execute(Chmod('file', "ugo+w"))
env.Command(
'foo.out',
'foo.in',
[Copy('$TARGET', '$SOURCE'), Chmod('$TARGET', "ugo+w")],
)
The behavior of Chmod is limited on Windows, see the notes in the Python documentation for os.chmod, which is the underlying function.
Copy(dest, src)
Execute(Copy('foo.output', 'foo.input'))
env.Command('bar.out', 'bar.in', Copy('$TARGET', '$SOURCE'))
Delete(entry, [must_exist])
Execute(Delete('/tmp/buildroot'))
env.Command(
'foo.out',
'foo.in',
action=[
Delete('${TARGET.dir}'),
MyBuildAction,
],
)
Execute(Delete('file_that_must_exist', must_exist=True))
Mkdir(name)
Execute(Mkdir('/tmp/outputdir'))
env.Command(
'foo.out',
'foo.in',
action=[
Mkdir('/tmp/builddir'),
Copy('/tmp/builddir/foo.in', '$SOURCE'),
"cd /tmp/builddir && make",
Copy('$TARGET', '/tmp/builddir/foo.out'),
],
)
Move(dest, src)
Execute(Move('file.destination', 'file.source'))
env.Command(
'output_file',
'input_file',
action=[MyBuildAction, Move('$TARGET', 'file_created_by_MyBuildAction')],
)
Touch(file)
Execute(Touch('file_to_be_touched'))
env.Command('marker', 'input_file', action=[MyBuildAction, Touch('$TARGET')])
Variable Substitution
Before executing a command, scons performs parameter expansion (substitution) on the string that makes up the action part of the builder. The format of a substitutable parameter is ${expression}. If expression refers to a variable, the braces in ${expression} can be omitted unless the variable name is immediately followed by a character that could either be interpreted as part of the name, or is Python syntax such as [ (for indexing/slicing) or . (for attribute access - see Special Attributes below).
If expression refers to a construction variable, it is replaced with the value of that variable in the construction environment at the time of execution. If expression looks like a variable name but is not defined in the construction environment it is replaced with an empty string. If expression refers to one of the Special Variables (see below) the corresponding value of the variable is substituted. expression may also be a Python expression to be evaluated. See Python Code Substitution below for a description.
SCons uses the following rules when converting construction variables into command line strings:
When a build action is executed, a hash of the command line is saved, together with other information about the target(s) built by the action, for future use in rebuild determination. This is called the build signature (or build action signature). The escape sequence $( subexpression $) may be used to indicate parts of a command line that may change without causing a rebuild--that is, which are not to be included when calculating the build signature. All text from $( up to and including the matching $) will be removed from the command line before it is added to the build signature while only the $( and $) will be removed before the command is executed. For example, the command line string:
"echo Last build occurred $( $TODAY $). > $TARGET"
would execute the command:
echo Last build occurred $TODAY. > $TARGET
but the build signature added to any target files would be computed from:
echo Last build occurred . > $TARGET
While construction variables are normally directly substituted, if a construction variable has a value which is a callable Python object (a function, or a class with a __call__ method), that object is called during substitution. The callable must accept four arguments: target, source, env and for_signature. source is a list of source nodes, target is a list of target nodes, env is the construction environment to use for context, and for_signature is a boolean value that tells the callable if it is being called for the purpose of generating a build signature. Since the build signature is used for rebuild determination, variable elements that do not affect whether a rebuild should be triggered should be omitted from the returned string if for_signature is true. See $( and $) above for the syntax.
SCons will insert whatever the callable returns into the expanded string:
def foo(target, source, env, for_signature):
return "bar" # Will expand $BAR to "bar baz" env = Environment(FOO=foo, BAR="$FOO baz")
As a reminder, substitution happens when $BAR is actually used in a builder action. The value of env['BAR'] will be exactly as it was set: "$FOO baz". This can make debugging tricky, as the substituted result is not available at the time the SConscript files are being interpreted and thus not available to the print function. However, you can perform the substitution on demand by calling the env.subst method for this purpose.
You can use this feature to pass arguments to a callable variable by creating a callable class that stores passed arguments in the instance, and then uses them (in the __call__ method) when the instance is called. Note that in this case, the entire variable expansion must be enclosed by curly braces so that the arguments will be associated with the instantiation of the class:
class foo:
def __init__(self, arg):
self.arg = arg
def __call__(self, target, source, env, for_signature):
return self.arg + " bar" # Will expand $BAR to "my argument bar baz" env=Environment(FOO=foo, BAR="${FOO('my argument')} baz")
Substitution: Special Variables
Besides regular construction variables, scons provides the following Special Variables for use in expanding commands:
$CHANGED_SOURCES
$CHANGED_TARGETS
$SOURCE
$SOURCES
$TARGET
$TARGETS
$UNCHANGED_SOURCES
$UNCHANGED_TARGETS
These names are reserved and may not be assigned to or used as construction variables. SCons computes them in a context-dependent manner and they and are not retrieved from a construction environment.
For example, the following builder call:
env = Environment(CC='cc') env.Command(
target=['foo'],
source=['foo.c', 'bar.c'],
action='@echo $CC -c -o $TARGET $SOURCES' )
would produce the following output:
cc -c -o foo foo.c bar.c
In the previous example, a string ${SOURCES[1]} would expand to: bar.c.
Substitution: Special Attributes
A variable name may have the following modifiers appended within the enclosing curly braces to access properties of the interpolated string. These are known as special attributes.
The base path of the file name,
including the directory path
but excluding any suffix.
The path with directories separated by forward slashes
(/).
Sometimes necessary on Windows systems
when a path references a file on other (POSIX) systems.
The path with directories separated by backslashes
(\\).
Sometimes necessary on POSIX-style systems
when a path references a file on other (Windows) systems.
win32 is a (deprecated) synonym for
windows.
The directory and file name to the source file linked to this file through
VariantDir().
If this file isn't linked,
it just returns the directory and filename unchanged.
The directory containing the source file linked to this file through
VariantDir().
If this file isn't linked,
it just returns the directory part of the filename.
The directory and file name to the source file linked to this file through
VariantDir().
If the file does not exist locally but exists in a Repository,
the path in the Repository is returned.
If this file isn't linked, it just returns the
directory and filename unchanged.
The Repository directory containing the source file linked to this file through
VariantDir().
If this file isn't linked,
it just returns the directory part of the filename.
For example, the specified target will expand as follows for the corresponding modifiers:
$TARGET => sub/dir/file.x
${TARGET.base} => sub/dir/file
${TARGET.dir} => sub/dir
${TARGET.file} => file.x
${TARGET.filebase} => file
${TARGET.suffix} => .x
${TARGET.abspath} => /top/dir/sub/dir/file.x
${TARGET.relpath} => sub/dir/file.x
$TARGET => ../dir2/file.x
${TARGET.abspath} => /top/dir2/file.x
${TARGET.relpath} => ../dir2/file.x
SConscript('src/SConscript', variant_dir='sub/dir')
$SOURCE => sub/dir/file.x
${SOURCE.srcpath} => src/file.x
${SOURCE.srcdir} => src
Repository('/usr/repository')
$SOURCE => sub/dir/file.x
${SOURCE.rsrcpath} => /usr/repository/src/file.x
${SOURCE.rsrcdir} => /usr/repository/src
Some modifiers can be combined, like ${TARGET.srcpath.base), ${TARGET.file.suffix}, etc.
Python Code Substitution
If a substitutable expression using the notation ${expression} does not appear to match one of the other substitution patterns, it is evaluated as a Python expression. This uses Python's eval function, with the globals parameter set to the current environment's set of construction variables, and the result substituted in. So in the following case:
env.Command(
'foo.out', 'foo.in', "echo ${COND==1 and 'FOO' or 'BAR'} > $TARGET" )
the command executed will be either
echo FOO > foo.out
or
echo BAR > foo.out
according to the current value of env['COND'] when the command is executed. The evaluation takes place when the target is being built, not when the SConscript is being read. So if env['COND'] is changed later in the SConscript, the final value will be used.
Here's a more complete example. Note that all of COND, FOO, and BAR are construction variables, and their values are substituted into the final command. FOO is a list, so its elements are interpolated separated by spaces.
env=Environment() env['COND'] = 1 env['FOO'] = ['foo1', 'foo2'] env['BAR'] = 'barbar' env.Command(
'foo.out', 'foo.in', "echo ${COND==1 and FOO or BAR} > $TARGET" )
will execute:
echo foo1 foo2 > foo.out
In point of fact, Python expression evaluation is how the special attributes are substituted: they are simply attributes of the Python objects that represent $TARGET, $SOURCES, etc., which SCons passes to eval which returns the value.
Caution
Use of the Python eval function is considered to have security implications, since, depending on input sources, arbitrary unchecked strings of code can be executed by the Python interpreter. Although SCons makes use of it in a somewhat restricted context, you should be aware of this issue when using the ${python-expression-for-subst} form.
Scanner Objects¶
Scanner objects are used to scan specific file types for implicit dependencies, for example embedded preprocessor/compiler directives that cause other files to be included during processing. SCons has a number of pre-built Scanner objects, so it is usually only necessary to set up Scanners for new file types. You do this by calling the Scanner factory function. Scanner accepts the following arguments. Only function is required; the rest are optional:
function
The function can use use str(node) to fetch the name of the file, node.dir to fetch the directory the file is in, node.get_contents() to fetch the contents of the file as bytes or node.get_text_contents() to fetch the contents of the file as text.
The function must take into account the path directories when generating the dependency Nodes. To illustrate this, a C language source file may contain a line like #include "foo.h". However, there is no guarantee that foo.h exists in the current directory: the contents of $CPPPATH is passed to the C preprocessor which will look in those places for the header, so the scanner function needs to look in those places as well in order to build Nodes with correct paths. Using FindPathDirs with an argument of CPPPATH as the path_function in the Scanner call means the scanner function will be called with the paths extracted from $CPPPATH in the environment env passed as the paths parameter.
Note that the file to scan is not guaranteed to exist at the time the scanner is called - it could be a generated file which has not been generated yet - so the scanner function must be tolerant of that.
Alternatively, you can supply a dictionary as the function parameter, to map keys (such as file suffixes) to other Scanner objects. A Scanner created this way serves as a dispatcher: the Scanner's skeys parameter is automatically populated with the dictionary's keys, indicating that the Scanner handles Nodes which would be selected by those keys; the mapping is then used to pass the file on to a different Scanner that would not have been selected to handle that Node based on its own skeys.
name
argument
skeys
path_function
node_class
node_factory
scan_check
recursive
Once created, a Scanner can added to an environment by setting it in the $SCANNERS list, which automatically triggers SCons to also add it to the environment as a method. However, usually a scanner is not truly standalone, but needs to be plugged in to the existing selection mechanism for deciding how to scan source files based on filename extensions. For this, SCons has a global SourceFileScanner object that is used by the Object, SharedObject and StaticObject builders to decide which scanner should be used. You can use the SourceFileScanner.add_scanner() method to add your own Scanner object to the SCons infrastructure that builds target programs or libraries from a list of source files of different types:
def xyz_scan(node, env, path):
contents = node.get_text_contents()
# Scan the contents and return the included files. XYZScanner = Scanner(xyz_scan) SourceFileScanner.add_scanner('.xyz', XYZScanner) env.Program('my_prog', ['file1.c', 'file2.f', 'file3.xyz'])
Tool Modules¶
Additional tools can be added to a project either by placing them in a site_tools subdirectory of a site directory, or in a custom location specified to scons by giving the toolpath keyword argument to Environment. A tool module is a form of Python module, invoked internally using the Python import mechanism, so a tool can consist either of a single source file taking the name of the tool (e.g. mytool.py) or a directory taking the name of the tool (e.g. mytool/) which contains at least an __init__.py file.
The toolpath parameter takes a list as its value:
env = Environment(tools=['default', 'foo'], toolpath=['tools'])
This looks for a tool specification module (mytool.py, or directory mytool) in directory tools and in the standard locations, as well as using the ordinary default tools for the platform.
Directories specified via toolpath are prepended to the existing tool path. The default tool path is any site_tools directories, so tools in a specified toolpath take priority, followed by tools in a site_tools directory, followed by built-in tools. For example, adding a tool specification module gcc.py to the toolpath directory would override the built-in gcc tool. The tool path is stored in the environment and will be used by subsequent calls to the Tool method, as well as by env.Clone.
base = Environment(toolpath=['custom_path']) derived = base.Clone(tools=['custom_tool']) derived.CustomBuilder()
A tool specification module must include two functions:
generate(env, **kwargs)
def generate(env):
...
if 'MYTOOL' not in env:
env['MYTOOL'] = env.Detect("mytool")
if 'MYTOOLFLAGS' not in env:
env['MYTOOLFLAGS'] = SCons.Util.CLVar('--myarg')
...
The generate function may use any keyword arguments that the user supplies via kwargs to vary its initialization.
exists(env)
Note
At the moment, user-added tools do not automatically have their exists function called. As a result, it is recommended that the generate function be defensively coded - that is, do not rely on any necessary existence checks already having been performed. This is expected to be a temporary limitation, and the exists function should still be provided.
The elements of the tools list may also be functions or callable objects, in which case the Environment method will call those objects to update the new construction environment (see Tool for more details):
def my_tool(env):
env['XYZZY'] = 'xyzzy' env = Environment(tools=[my_tool])
The individual elements of the tools list may also themselves be lists or tuples of the form (toolname, kw_dict). SCons searches for the toolname specification file as described above, and passes kw_dict, which must be a dictionary, as keyword arguments to the tool's generate function. The generate function can use the arguments to modify the tool's behavior by setting up the environment in different ways or otherwise changing its initialization.
# in tools/my_tool.py: def generate(env, **kwargs):
# Sets MY_TOOL to the value of keyword 'arg1' '1' if not supplied
env['MY_TOOL'] = kwargs.get('arg1', '1') def exists(env):
return True # in SConstruct: env = Environment(tools=['default', ('my_tool', {'arg1': 'abc'})],
toolpath=['tools'])
The tool specification (my_tool in the example) can use the $PLATFORM variable from the construction environment it is passed to customize the tool for different platforms.
Tools can be "nested" - that is, they can be located within a subdirectory in the toolpath. A nested tool name uses a dot to represent a directory separator
# namespaced builder env = Environment(ENV=os.environ.copy(), tools=['SubDir1.SubDir2.SomeTool']) env.SomeTool(targets, sources) # Search Paths # SCons\Tool\SubDir1\SubDir2\SomeTool.py # SCons\Tool\SubDir1\SubDir2\SomeTool\__init__.py # .\site_scons\site_tools\SubDir1\SubDir2\SomeTool.py # .\site_scons\site_tools\SubDir1\SubDir2\SomeTool\__init__.py
SYSTEM-SPECIFIC BEHAVIOR¶
scons and its configuration files are very portable, due largely to its implementation in Python. There are, however, a few portability issues waiting to trap the unwary.
.C File Suffix¶
scons handles the upper-case .C file suffix differently, depending on the capabilities of the underlying system. On a case-sensitive system such as Linux or UNIX, scons treats a file with a .C suffix as a C++ source file. On a case-insensitive system such as Windows, scons treats a file with a .C suffix as a C source file.
Fortran File Suffixes¶
There are several ways source file suffixes impact the behavior of SCons when working with Fortran language code (not all are system-specific, but they are included here for completeness).
As the Fortran language has evolved through multiple standards editions, projects might have a need to handle files from different language generations differently. To this end, SCons dispatches to a different compiler dialect setup (expressed as a set of construction variables) depending on the file suffix. By default, all of these setups start out the same, but individual construction variables can be modified as needed to tune a given dialect. Each of these dialacts has a tool specification module whose documentation describes the construction variables associated with that dialect: .f (as well as .for and .ftn) in fortran; (construction variables start with FORTRAN) .f77 in f77; (construction variables start with F77) .f90 in f90; (construction variables start with F90) .f95 in f95; (construction variables start with F95) .f03 in f03; (construction variables start with F03) .f08 in f08 (construction variables start with F08).
While SCons recognizes multiple internal dialects based on filename suffixes, the convention of various available Fortran compilers is to assign an actual meaning to only two of these suffixes: .f (as well as .for and .ftn) refers to the fixed-format source code that was the only available option in FORTRAN 77 and earlier, and .f90 refers to free-format source code which became available as of the Fortran 90 standard. Some compilers recognize suffixes which correspond to Fortran specifications later then F90 as equivalent to .f90 for this purpose, while some do not - check the documentation for your compiler. An occasionally suggested policy suggestion is to use only .f and .f90 as Fortran filename suffixes. The fixed/free form determination can usually be controlled explicitly with compiler flags (e.g. -ffixed-form for gfortran), overriding any assumption that may be made based on the source file suffix.
The source file suffix does not imply conformance with the similarly-named Fortran standard - a suffix of .f08 does not mean you are compiling specifically for Fortran 2008. Normally, compilers provide command-line options for making this selection (e.g. -std=f2008 for gfortran).
For dialects from F90 on (including the generic FORTRAN dialect), a suffix of .mod is recognized for Fortran modules. These files are a side effect of compiling a Fortran source file containing module declarations, and must be available when other code which declares that it uses the module is processed. SCons does not currently have integrated support for submodules, introduced in the Fortran 2008 standard - the invoked compiler will produce results, but SCons will not recognize .smod files as tracked objects.
On a case-sensitive system such as Linux or UNIX, a file with a an upper-cased suffix from the set .F, .FOR, .FTN, .F90, .F95, .F03 and .F08 is treated as a Fortran source file which shall first be run through the standard C preprocessor. The lower-cased versions of these suffixes do not trigger this behavior. On systems which do not distinguish between uppper and lower case in filenames, this behavior is not available, but files suffixed with either .FPP or .fpp are always passed to the preprocessor first. This matches the convention of gfortran from the GNU Compiler Collection, and also followed by certain other Fortran compilers. For these two suffixes, the generic FORTRAN dialect will be selected.
SCons itself does not invoke the preprocessor, that is handled by the compiler, but it adds construction variables which are applicable to the preprocessor run. You can see this difference by examining $FORTRANPPCOM and $FORTRANPPCOMSTR which are used instead of $FORTRANCOM and $FORTRANCOMSTR for that dialect.
Windows: Cygwin Tools and Cygwin Python vs. Windows Pythons¶
Cygwin supplies a set of tools and utilities that let users work on a Windows system using a POSIX-like environment. The Cygwin tools, including Cygwin Python, do this, in part, by sharing an ability to interpret POSIX-style path names. For example, the Cygwin tools will internally translate a Cygwin path name like /cygdrive/c/mydir to an equivalent Windows pathname of C:/mydir (equivalent to C:\mydir).
Versions of Python that are built for native Windows execution, such as the python.org and ActiveState versions, do not understand the Cygwin path name semantics. This means that using a native Windows version of Python to build compiled programs using Cygwin tools (such as gcc, bison and flex) may yield unpredictable results. "Mixing and matching" in this way can be made to work, but it requires careful attention to the use of path names in your SConscript files.
In practice, users can sidestep the issue by adopting the following guidelines: When using Cygwin's gcc for compiling, use the Cygwin-supplied Python interpreter to run scons; when using Microsoft Visual C/C++ (or some other "native" Windows compiler) use the python.org, Microsoft Store, ActiveState or other native version of Python to run scons.
This discussion largely applies to the msys2 environment as well (with the use of the mingw compiler toolchain), in particular the recommendation to use the msys2 version of Python if running scons from inside an msys2 shell.
Windows: scons.bat file¶
On Windows, if scons is executed via a wrapper scons.bat batch file, there are (at least) two ramifications. Note this is no longer the default - scons installed via Python''s pip installer will have an scons.exe which does not have these limitations:
First, Windows command-line users that want to use variable assignment on the command line may have to put double quotes around the assignments, otherwise the Windows command shell will consume those as arguments to itself, not to scons:
scons "FOO=BAR" "BAZ=BLEH"
Second, the Cygwin shell does not recognize typing scons at the command line prompt as referring to this wrapper. You can work around this either by executing scons.bat (including the extension) from the Cygwin command line, or by creating a wrapper shell script named scons which invokes scons.bat.
MinGW¶
The MinGW bin directory must be in your PATH environment variable or the ['ENV']['PATH'] construction variable for scons to detect and use the MinGW tools. When running under the native Windows Python; interpreter, scons will prefer the MinGW tools over the Cygwin tools, if they are both installed, regardless of the order of the bin directories in the PATH variable. If you have both MSVC and MinGW installed and you want to use MinGW instead of MSVC, then you must explicitly tell scons to use MinGW by passing tools=['mingw'] to the Environment function, because scons will prefer the MSVC tools over the MinGW tools.
ENVIRONMENT¶
In general, scons is not controlled by environment variables set in the shell used to invoke it, leaving it up to the SConscript file author to import those if desired. However the following variables are imported by scons itself if set:
SCONS_LIB_DIR
SCONSFLAGS
SCONS_CACHE_MSVC_CONFIG
If set to a True-like value ("1", "true" or "True") will cache to a file named scons_msvc_cache.json in the user's home directory. If set to a pathname, will use that pathname for the cache.
Note: this implementation may still be somewhat fragile. In case of problems, remove the cache file - recreating with fresh info normally resolves any issues. SCons ignores failures reading or writing the cache file and will silently revert to non-cached behavior in such cases.
New in 3.1 (experimental). The default cache file name was changed to its present value in 4.4, and contents were expanded.
QTDIR
SEE ALSO¶
The SCons User Guide at
https://scons.org/doc/production/HTML/scons-user.html
The SCons Cookbook at
https://scons-cookbook.readthedocs.io
for examples of how to solve various problems with SCons.
SCons source code
on GitHub[8]
The SCons API Reference
https://scons.org/doc/production/HTML/scons-api/index.html
(for internal details)
AUTHORS¶
Originally: Steven Knight knight@baldmt.com and Anthony Roach aroach@electriceyeball.com.
Since 2010: The SCons Development Team scons-dev@scons.org.
AUTHOR¶
The SCons Development Team
COPYRIGHT¶
Copyright © 2001 - 2021 The SCons Foundation
NOTES¶
- 2.
- LLVM specification
- 3.
- JEP 313
- 6.
- If no_progress is set via SetOption in an SConscript file (but not if set in a site_init.py file) there will still be an initial status message about reading SConscript files since SCons has to start reading them before it can see the SetOption.
- 7.
- http://www.opensource.org/licenses/alphabetical
- 8.
- on GitHub
| <pubdate>Released Sun, 18 Jul 2021 17:34:05 -0700</pubdate> | SCons __VERSION__ Version 4.2. |