MKC_CHECK_DECL(1)                                            MKC_CHECK_DECL(1)

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

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

DESCRIPTION
       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.

OPTIONS
       -h     display help message

ENVIRONMENT
       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.

EXAMPLES
          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

C FILE CONTENT
       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;
              }

AUTHOR
       Aleksey Cheusov <vle@gmx.net>

                                March 30, 2019               MKC_CHECK_DECL(1)