1 # serial 18 -*- Autoconf -*-
3 dnl Find out how to get the file descriptor associated with an open DIR*.
5 # Copyright (C) 2001-2006, 2008-2010 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 dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
21 AC_REQUIRE([AC_PROG_CPP])
22 AC_REQUIRE([AC_PROG_EGREP])
24 AC_CHECK_FUNCS([dirfd])
25 AC_CHECK_DECLS([dirfd], , ,
26 [#include <sys/types.h>
28 if test $ac_cv_have_decl_dirfd = no; then
32 AC_CACHE_CHECK([whether dirfd is a macro],
33 gl_cv_func_dirfd_macro,
34 [AC_EGREP_CPP([dirent_header_defines_dirfd], [
35 #include <sys/types.h>
38 dirent_header_defines_dirfd
40 gl_cv_func_dirfd_macro=yes,
41 gl_cv_func_dirfd_macro=no)])
43 # Use the replacement only if we have no function or macro with that name.
44 if test $ac_cv_func_dirfd,$gl_cv_func_dirfd_macro = no,no; then
45 if test $ac_cv_have_decl_dirfd = yes; then
46 # If the system declares dirfd already, let's declare rpl_dirfd instead.
51 [how to get the file descriptor associated with an open DIR*],
52 gl_cv_sys_dir_fd_member_name,
54 dirfd_save_CFLAGS=$CFLAGS
55 for ac_expr in d_fd dd_fd; do
57 CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
58 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
59 #include <sys/types.h>
60 #include <dirent.h>]],
61 [[DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;]])],
64 CFLAGS=$dirfd_save_CFLAGS
65 test "$dir_fd_found" = yes && break
67 test "$dir_fd_found" = yes || ac_expr=no_such_member
69 gl_cv_sys_dir_fd_member_name=$ac_expr
72 if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
73 AC_DEFINE_UNQUOTED([DIR_FD_MEMBER_NAME],
74 $gl_cv_sys_dir_fd_member_name,
75 [the name of the file descriptor member of DIR])
77 AH_VERBATIM(DIR_TO_FD,
78 [#ifdef DIR_FD_MEMBER_NAME
79 # define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
81 # define DIR_TO_FD(Dir_p) -1