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.\" Copyright (c) 2009-2010 by Aleksey Cheusov (vle@gmx.net)
.\" Absolutely no warranty.
.\"
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.TH MKC_CHECK_DECL 1 "Mar 30, 2019" "" ""
.SH NAME
mkc_check_decl \- checks for define, variable, function, type, member or
function prototype.
.SH SYNOPSIS
.BI mkc_check_decl " [OPTIONS] <check_type> <what> [headers...]"
.SH DESCRIPTION
.I check_type
is either
.IR " define" , " variable" , " func[0-9]" , " funcordefine[0-9]" , " type" , " member " or
.IR " prototype" .
Depending on its value
.B mkc_check_decl
checks respectively for define, variable, function with the specified number
of arguments (or equivalent define in case of funcordefine[0-9]),
data type, member of structure or a function prototype
in the specified
.I headers
by compiling a test program.
.I headers
is either a single header file or a list of headers, separated by comma.
As a result
.B mkc_check_decl
prints either 1 (success) or 0 (failure) to stdout.
By default, temporary and cache files
.RI _mkc_ <check_type> _ <what> _ <lheader_h> .{c,err,res}
are created under
.B MKC_CACHEDIR
directory. Here,
.I lheader_h
is the last header from comma-separated list
.IR headers .
.SH OPTIONS
.TP
.B "-h"
display help message
.SH ENVIRONMENT
.TP
.B CC
Compiler. By default
.I cc
is used.
.TP
.B CPPFLAGS, CFLAGS
Options passed to the compiler, for example -I for additional directories
that contain header files.
.TP
.B MKC_VERBOSE
If set to 1, verbose messages are output to stderr.
.TP
.B MKC_SHOW_CACHED
If set to 1 and MKC_VERBOSE is set to 1, cached results
are output to stderr.
.TP
.B MKC_COMMON_HEADERS
List of header files to add to .c test program.
.TP
.B MKC_CACHEDIR
Directory where temporary and cache files are created.
If unset they are created in a current directory.
.TP
.B MKC_NOCACHE
All results are cached unless MKC_NOCACHE variable is set
to 1.
.TP
.B MKC_DELETE_TMPFILES
If set to 1, temporary files are removed.
.SH EXAMPLES
.VS
   mkc_check_decl define __GNUC__
   mkc_check_decl define RTLD_LAZY dlfcn.h
   mkc_check_decl define FTS_W sys/types.h,sys/stat.h,fts.h
   mkc_check_decl variable sys_errlist errno.h
   mkc_check_decl variable __malloc_hook malloc.h
   mkc_check_decl func3 poll poll.h
   mkc_check_decl func2 fgetln stdio.h
   mkc_check_decl type mbstate_t wchar.h
   mkc_check_decl type long-long
   mkc_check_decl member tm.tm_isdst time.h
   mkc_check_decl member ifreq.ifr_addr.sa_len net/if.h
   mkc_check_decl member struct-stat.st_mtimespec sys/stat.h
   mkc_check_decl prototype 'int connect(int,const struct sockaddr*,socklen_t)' sys/socket.h
   mkc_check_decl prototype 'int connect(int,struct sockaddr*,socklen_t)' sys/socket.h
.VE
.SH C FILE CONTENT
.TP
.B define
.VS
#include <header1.h>
 ...
#include <headerN.h>

#if defined(WHAT)
int func(void)
{
   return 0;
}
#else
#error "WHAT is not a define"
#endif
.VE
.TP
.B variable
.VS
#include <header1.h>
 ...
#include <headerN.h>

int func(void)
{
   return sizeof ((WHAT)) && (&WHAT != 0);
}
.VE
.TP
.BR func3 " (example for function with 3 arguments)"
.VS
#include <header1.h>
 ...
#include <headerN.h>

void func (void)
{
   if (WHAT) return;
   WHAT(0,0,0);
}
.VE
.TP
.BR funcordefine3 " (example for function/define with 3 arguments)"
.VS
#include <header1.h>
 ...
#include <headerN.h>

void func (void)
{
   WHAT(0,0,0);
}
.VE
.TP
.B type
.VS
#include <header1.h>
 ...
#include <headerN.h>

int func(void)
{
   return sizeof (WHAT);
}
.VE
.TP
.B member " (example for struct stat.st_mtimespec)"
.VS
#include <sys/stat.h>
int func(void)
{
   struct_stat var;
   return sizeof (var.st_mtimespec);
}
.VE
.TP
.BR prototype " (example for void ttt(int,char**) function)"
.VS
#include <header1.h>
 ...
#include <headerN.h>

void func (void);
void func2 (void);

void func (void)
{
   if (ttt) return;
}

void ttt(int, char**);

void func2 (void)
{
   if (ttt) return;
}
.VE
.SH AUTHOR
Aleksey Cheusov <vle@gmx.net>