1 # serial 19 -*- Autoconf -*-
3 dnl Find out how to get the file descriptor associated with an open DIR*.
5 # Copyright (C) 2001-2006, 2008-2011 Free Software Foundation, Inc.
6 # This file is free software; the Free Software Foundation
7 # gives unlimited permission to copy and/or distribute it,
8 # with or without modifications, as long as this notice is preserved.
12 AC_DEFUN([gl_FUNC_DIRFD],
14 AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
17 dnl Persuade glibc <dirent.h> to declare dirfd().
18 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
20 AC_CHECK_FUNCS([dirfd])
21 AC_CHECK_DECLS([dirfd], , ,
22 [#include <sys/types.h>
24 if test $ac_cv_have_decl_dirfd = no; then
28 AC_CACHE_CHECK([whether dirfd is a macro],
29 gl_cv_func_dirfd_macro,
30 [AC_EGREP_CPP([dirent_header_defines_dirfd], [
31 #include <sys/types.h>
34 dirent_header_defines_dirfd
36 gl_cv_func_dirfd_macro=yes,
37 gl_cv_func_dirfd_macro=no)])
39 # Use the replacement only if we have no function or macro with that name.
40 if test $ac_cv_func_dirfd,$gl_cv_func_dirfd_macro = no,no; then
41 if test $ac_cv_have_decl_dirfd = yes; then
42 # If the system declares dirfd already, let's declare rpl_dirfd instead.
47 [how to get the file descriptor associated with an open DIR*],
48 gl_cv_sys_dir_fd_member_name,
50 dirfd_save_CFLAGS=$CFLAGS
51 for ac_expr in d_fd dd_fd; do
53 CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
54 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
55 #include <sys/types.h>
56 #include <dirent.h>]],
57 [[DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;]])],
60 CFLAGS=$dirfd_save_CFLAGS
61 test "$dir_fd_found" = yes && break
63 test "$dir_fd_found" = yes || ac_expr=no_such_member
65 gl_cv_sys_dir_fd_member_name=$ac_expr
68 if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
69 AC_DEFINE_UNQUOTED([DIR_FD_MEMBER_NAME],
70 $gl_cv_sys_dir_fd_member_name,
71 [the name of the file descriptor member of DIR])
73 AH_VERBATIM(DIR_TO_FD,
74 [#ifdef DIR_FD_MEMBER_NAME
75 # define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
77 # define DIR_TO_FD(Dir_p) -1