1 #serial 13 -*- Autoconf -*-
3 dnl Find out how to get the file descriptor associated with an open DIR*.
5 # Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006 Free Software
7 # This file is free software; the Free Software Foundation
8 # gives unlimited permission to copy and/or distribute it,
9 # with or without modifications, as long as this notice is preserved.
13 AC_DEFUN([gl_FUNC_DIRFD],
15 AC_LIBSOURCES([dirfd.c, dirfd.h])
17 dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
18 AC_REQUIRE([AC_PROG_CPP])
19 AC_REQUIRE([AC_PROG_EGREP])
21 AC_CHECK_DECLS([dirfd], , ,
22 [#include <sys/types.h>
25 AC_CACHE_CHECK([whether dirfd is a macro],
26 gl_cv_func_dirfd_macro,
27 [AC_EGREP_CPP([dirent_header_defines_dirfd], [
28 #include <sys/types.h>
31 dirent_header_defines_dirfd
33 gl_cv_func_dirfd_macro=yes,
34 gl_cv_func_dirfd_macro=no)])
36 # Use the replacement only if we have no function, macro,
37 # or declaration with that name.
38 if test $ac_cv_func_dirfd,$ac_cv_have_decl_dirfd,$gl_cv_func_dirfd_macro \
40 AC_REPLACE_FUNCS([dirfd])
42 [how to get the file descriptor associated with an open DIR*],
43 gl_cv_sys_dir_fd_member_name,
45 dirfd_save_CFLAGS=$CFLAGS
46 for ac_expr in d_fd dd_fd; do
48 CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
50 [#include <sys/types.h>
52 [DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;],
55 CFLAGS=$dirfd_save_CFLAGS
56 test "$dir_fd_found" = yes && break
58 test "$dir_fd_found" = yes || ac_expr=no_such_member
60 gl_cv_sys_dir_fd_member_name=$ac_expr
63 if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
64 AC_DEFINE_UNQUOTED(DIR_FD_MEMBER_NAME,
65 $gl_cv_sys_dir_fd_member_name,
66 [the name of the file descriptor member of DIR])
68 AH_VERBATIM(DIR_TO_FD,
69 [#ifdef DIR_FD_MEMBER_NAME
70 # define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
72 # define DIR_TO_FD(Dir_p) -1