1 #serial 15 -*- 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, 2008 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_REQUIRE([gl_DIRENT_H_DEFAULTS])
18 dnl Persuade glibc <dirent.h> to declare dirfd().
19 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
21 dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
22 AC_REQUIRE([AC_PROG_CPP])
23 AC_REQUIRE([AC_PROG_EGREP])
26 AC_CHECK_DECLS([dirfd], , ,
27 [#include <sys/types.h>
29 if test $ac_cv_have_decl_dirfd = no; then
33 AC_CACHE_CHECK([whether dirfd is a macro],
34 gl_cv_func_dirfd_macro,
35 [AC_EGREP_CPP([dirent_header_defines_dirfd], [
36 #include <sys/types.h>
39 dirent_header_defines_dirfd
41 gl_cv_func_dirfd_macro=yes,
42 gl_cv_func_dirfd_macro=no)])
44 # Use the replacement only if we have no function, macro,
45 # or declaration with that name.
46 if test $ac_cv_func_dirfd,$ac_cv_have_decl_dirfd,$gl_cv_func_dirfd_macro \
48 AC_REPLACE_FUNCS([dirfd])
50 [how to get the file descriptor associated with an open DIR*],
51 gl_cv_sys_dir_fd_member_name,
53 dirfd_save_CFLAGS=$CFLAGS
54 for ac_expr in d_fd dd_fd; do
56 CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
58 [#include <sys/types.h>
60 [DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;],
63 CFLAGS=$dirfd_save_CFLAGS
64 test "$dir_fd_found" = yes && break
66 test "$dir_fd_found" = yes || ac_expr=no_such_member
68 gl_cv_sys_dir_fd_member_name=$ac_expr
71 if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
72 AC_DEFINE_UNQUOTED(DIR_FD_MEMBER_NAME,
73 $gl_cv_sys_dir_fd_member_name,
74 [the name of the file descriptor member of DIR])
76 AH_VERBATIM(DIR_TO_FD,
77 [#ifdef DIR_FD_MEMBER_NAME
78 # define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
80 # define DIR_TO_FD(Dir_p) -1