1 #serial 14 -*- 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 dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
16 AC_REQUIRE([AC_PROG_CPP])
17 AC_REQUIRE([AC_PROG_EGREP])
19 AC_CHECK_DECLS([dirfd], , ,
20 [#include <sys/types.h>
23 AC_CACHE_CHECK([whether dirfd is a macro],
24 gl_cv_func_dirfd_macro,
25 [AC_EGREP_CPP([dirent_header_defines_dirfd], [
26 #include <sys/types.h>
29 dirent_header_defines_dirfd
31 gl_cv_func_dirfd_macro=yes,
32 gl_cv_func_dirfd_macro=no)])
34 # Use the replacement only if we have no function, macro,
35 # or declaration with that name.
36 if test $ac_cv_func_dirfd,$ac_cv_have_decl_dirfd,$gl_cv_func_dirfd_macro \
38 AC_REPLACE_FUNCS([dirfd])
40 [how to get the file descriptor associated with an open DIR*],
41 gl_cv_sys_dir_fd_member_name,
43 dirfd_save_CFLAGS=$CFLAGS
44 for ac_expr in d_fd dd_fd; do
46 CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
48 [#include <sys/types.h>
50 [DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;],
53 CFLAGS=$dirfd_save_CFLAGS
54 test "$dir_fd_found" = yes && break
56 test "$dir_fd_found" = yes || ac_expr=no_such_member
58 gl_cv_sys_dir_fd_member_name=$ac_expr
61 if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
62 AC_DEFINE_UNQUOTED(DIR_FD_MEMBER_NAME,
63 $gl_cv_sys_dir_fd_member_name,
64 [the name of the file descriptor member of DIR])
66 AH_VERBATIM(DIR_TO_FD,
67 [#ifdef DIR_FD_MEMBER_NAME
68 # define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
70 # define DIR_TO_FD(Dir_p) -1