MKC_CHECK_DECL(1) MKC_CHECK_DECL(1)

mkc_check_decl - checks for define, variable, function, type, member or function prototype.

mkc_check_decl [OPTIONS] <check_type> <what> [headers...]

check_type is either define, variable, func[0-9], funcordefine[0-9], type, member or prototype. Depending on its value 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 headers by compiling a test program. headers is either a single header file or a list of headers, separated by comma. As a result mkc_check_decl prints either 1 (success) or 0 (failure) to stdout. By default, temporary and cache files _mkc_<check_type>_<what>_<lheader_h>.{c,err,res} are created under MKC_CACHEDIR directory. Here, lheader_h is the last header from comma-separated list headers.

-h
display help message

CC
Compiler. By default cc is used.
CPPFLAGS, CFLAGS
Options passed to the compiler, for example -I for additional directories that contain header files.
MKC_VERBOSE
If set to 1, verbose messages are output to stderr.
MKC_SHOW_CACHED
If set to 1 and MKC_VERBOSE is set to 1, cached results are output to stderr.
MKC_COMMON_HEADERS
List of header files to add to .c test program.
MKC_CACHEDIR
Directory where temporary and cache files are created. If unset they are created in a current directory.
MKC_NOCACHE
All results are cached unless MKC_NOCACHE variable is set to 1.
MKC_DELETE_TMPFILES
If set to 1, temporary files are removed.

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

define
#include <header1.h>
 ...
#include <headerN.h>
#if defined(WHAT)
int func(void)
{
   return 0;
}
#else
#error "WHAT is not a define"
#endif
variable
#include <header1.h>
 ...
#include <headerN.h>
int func(void)
{
   return sizeof ((WHAT)) && (&WHAT != 0);
}
func3 (example for function with 3 arguments)
#include <header1.h>
 ...
#include <headerN.h>
void func (void)
{
   if (WHAT) return;
   WHAT(0,0,0);
}
funcordefine3 (example for function/define with 3 arguments)
#include <header1.h>
 ...
#include <headerN.h>
void func (void)
{
   WHAT(0,0,0);
}
type
#include <header1.h>
 ...
#include <headerN.h>
int func(void)
{
   return sizeof (WHAT);
}
member (example for struct stat.st_mtimespec)
#include <sys/stat.h>
int func(void)
{
   struct_stat var;
   return sizeof (var.st_mtimespec);
}
prototype (example for void ttt(int,char**) function)
#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;
}

Aleksey Cheusov <vle@gmx.net>
March 30, 2019