SYNTAX¶

oshcc [--showme | --showme:compile | --showme:link] ...

oshcxx [--showme | --showme:compile | --showme:link] ...

oshc++ [--showme | --showme:compile | --showme:link] ...

oshfort [--showme | --showme:compile | --showme:link] ...

shmemcc [--showme | --showme:compile | --showme:link] ...

shmemcxx [--showme | --showme:compile | --showme:link] ...

shmemc++ [--showme | --showme:compile | --showme:link] ...

shmemfort [--showme | --showme:compile | --showme:link] ...

OPTIONS¶

The options below apply to all of the wrapper compilers:

See the man page for your underlying compiler for other options that can be passed through oshcc.

DESCRIPTION¶

Conceptually, the role of these commands is quite simple: transparently add relevant compiler and linker flags to the user’s command line that are necessary to compile / link OpenSHMEM programs, and then invoke the underlying compiler to actually perform the command.

As such, these commands are frequently referred to as “wrapper” compilers because they do not actually compile or link applications themselves; they only add in command line flags and invoke the back-end compiler.

BACKGROUND¶

Open MPI provides wrapper compilers for several languages:

The wrapper compilers for each of the languages are identical; they can be use interchangeably. The different names are provided solely for backwards compatibility.

FORTRAN NOTES¶

The Fortran wrapper compiler for OpenSHMEM (oshfort and shmemfort) can compile and link OpenSHMEM applications that use any/all of the OpenSHMEM Fortran bindings.

Note, however, that the Fortran compiler may require additional command-line options to enforce a specific Fortran dialect. For example, in some versions of the IBM XLF compiler, if xlf90 is the underlying Fortran compiler, -qfixed may be necessary to compile fixed-format Fortran source files.

Finally, note that oshfort will be inoperative and will return an error on use if Fortran support was not built into the OpenSHMEM layer.

OVERVIEW¶

oshcc and shmemcc are convenience wrappers for the underlying C compiler. Translation of an OpenSHMEM program requires the linkage of the OpenSHMEM-specific libraries which may not reside in one of the standard search directories of ld(1). It also often requires the inclusion of header files what may also not be found in a standard location.

oshcc and shmemcc pass their arguments to the underlying C compiler along with the -I, -L and -l options required by OpenSHMEM programs.

The same is true for all the other language wrapper compilers.

The OpenSHMEM Team strongly encourages using the wrapper compilers instead of attempting to link to the OpenSHMEM libraries manually. This allows the specific implementation of OpenSHMEM to change without forcing changes to linker directives in users’ Makefiles. Indeed, the specific set of flags and libraries used by the wrapper compilers depends on how OpenSHMEM was configured and built; the values can change between different installations of the same version of OpenSHMEM.

Indeed, since the wrappers are simply thin shells on top of an underlying compiler, there are very, very few compelling reasons not to use oshcc. When it is not possible to use the wrappers directly, the --showme:compile and --showme:link options should be used to determine what flags the wrappers would have used. For example:

shell$ cc -c file1.c `shmemcc --showme:compile`
shell$ cc -c file2.c `shmemcc --showme:compile`
shell$ cc file1.o file2.o `shmemcc --showme:link` -o my_oshmem_program

NOTES¶

It is possible to make the wrapper compilers multi-lib aware. That is, the libraries and includes specified may differ based on the compiler flags specified (for example, with the GNU compilers on Linux, a different library path may be used if -m32 is seen versus -m64 being seen). This is not the default behavior in a standard build, but can be activated (for example, in a binary package providing both 32 and 64 bit support). More information can be found here.

FILES¶

The strings that the wrapper compilers insert into the command line before invoking the underlying compiler are stored in a text file created by OpenSHMEM and installed to $pkgdata/NAME-wrapper-data.txt, where:

It is rarely necessary to edit these files, but they can be examined to gain insight into what flags the wrappers are placing on the command line.

ENVIRONMENT VARIABLES¶

By default, the wrappers use the compilers that were selected when OpenSHMEM was configured. These compilers were either found automatically by Open MPI’s “configure” script, or were selected by the user in the CC, CXX, and/or FC environment variables before configure was invoked. Additionally, other arguments specific to the compiler may have been selected by configure.

These values can be selectively overridden by either editing the text files containing this configuration information (see the FILES section), or by setting selected environment variables of the form oshmem_value.

Valid value names are:

COPYRIGHT¶

2003-2024, The Open MPI Community