kc3-lang/gnulib/m4/dirfd.m4

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• Hash : faa4f9fd
  Author :
  Date : 2003-05-26T19:38:42
  

  (UTILS_FUNC_DIRFD): Test the cache variable, not one
  that is guaranteed to be `no'.  Use `no_such_member' to indicate
  that condition, rather than `-1' which is slightly misleading.
  Change the name of the cache variable to have the gl_ prefix.
  Prompted by a patch from Richard Dawe for DJGPP.
  

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• m4/dirfd.m4

• #serial 6
  
  dnl Find out how to get the file descriptor associated with an open DIR*.
  dnl From Jim Meyering
  
  AC_DEFUN([UTILS_FUNC_DIRFD],
  [
    dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
    AC_REQUIRE([AC_PROG_CPP])
    AC_REQUIRE([AC_PROG_EGREP])
  
    AC_HEADER_DIRENT
    dirfd_headers='
  #if HAVE_DIRENT_H
  # include <dirent.h>
  #else /* not HAVE_DIRENT_H */
  # define dirent direct
  # if HAVE_SYS_NDIR_H
  #  include <sys/ndir.h>
  # endif /* HAVE_SYS_NDIR_H */
  # if HAVE_SYS_DIR_H
  #  include <sys/dir.h>
  # endif /* HAVE_SYS_DIR_H */
  # if HAVE_NDIR_H
  #  include <ndir.h>
  # endif /* HAVE_NDIR_H */
  #endif /* HAVE_DIRENT_H */
  '
    AC_CHECK_FUNCS(dirfd)
    AC_CHECK_DECLS([dirfd], , , $dirfd_headers)
  
    AC_CACHE_CHECK([whether dirfd is a macro],
      jm_cv_func_dirfd_macro,
      [AC_EGREP_CPP([dirent_header_defines_dirfd], [$dirfd_headers
  #ifdef dirfd
   dirent_header_defines_dirfd
  #endif],
         jm_cv_func_dirfd_macro=yes,
         jm_cv_func_dirfd_macro=no)])
  
    # Use the replacement only if we have no function, macro,
    # or declaration with that name.
    if test $ac_cv_func_dirfd,$ac_cv_have_decl_dirfd,$jm_cv_func_dirfd_macro \
        = no,no,no; then
      AC_REPLACE_FUNCS([dirfd])
      AC_CACHE_CHECK(
  	      [how to get the file descriptor associated with an open DIR*],
  		   gl_cv_sys_dir_fd_member_name,
        [
          dirfd_save_CFLAGS=$CFLAGS
  	for ac_expr in d_fd dd_fd; do
  
  	  CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
  	  AC_TRY_COMPILE(
  	    [$dirfd_headers
  	    ],
  	    [DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;],
  	    dir_fd_found=yes
  	  )
  	  CFLAGS=$dirfd_save_CFLAGS
  	  test "$dir_fd_found" = yes && break
  	done
  	test "$dir_fd_found" = yes || ac_expr=no_such_member
  
  	gl_cv_sys_dir_fd_member_name=$ac_expr
        ]
      )
      if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
        AC_DEFINE_UNQUOTED(DIR_FD_MEMBER_NAME,
  	$gl_cv_sys_dir_fd_member_name,
  	[the name of the file descriptor member of DIR])
      fi
      AH_VERBATIM(DIR_TO_FD,
  		[#ifdef DIR_FD_MEMBER_NAME
  # define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
  #else
  # define DIR_TO_FD(Dir_p) -1
  #endif
  ]
      )
    fi
  ])
  

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