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49e4877c | 1 | # serial 24 -*- Autoconf -*- |
18848e28 GF |
2 | |
3 | dnl Find out how to get the file descriptor associated with an open DIR*. | |
4 | ||
49e4877c | 5 | # Copyright (C) 2001-2006, 2008-2016 Free Software Foundation, Inc. |
18848e28 GF |
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. | |
9 | ||
10 | dnl From Jim Meyering | |
11 | ||
12 | AC_DEFUN([gl_FUNC_DIRFD], | |
13 | [ | |
14 | AC_REQUIRE([gl_DIRENT_H_DEFAULTS]) | |
15 | ||
16 | dnl Persuade glibc <dirent.h> to declare dirfd(). | |
17 | AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) | |
18 | ||
19 | AC_CHECK_FUNCS([dirfd]) | |
20 | AC_CHECK_DECLS([dirfd], , , | |
21 | [[#include <sys/types.h> | |
22 | #include <dirent.h>]]) | |
23 | if test $ac_cv_have_decl_dirfd = no; then | |
24 | HAVE_DECL_DIRFD=0 | |
25 | fi | |
26 | ||
27 | AC_CACHE_CHECK([whether dirfd is a macro], | |
28 | gl_cv_func_dirfd_macro, | |
29 | [AC_EGREP_CPP([dirent_header_defines_dirfd], [ | |
30 | #include <sys/types.h> | |
31 | #include <dirent.h> | |
32 | #ifdef dirfd | |
33 | dirent_header_defines_dirfd | |
34 | #endif], | |
35 | gl_cv_func_dirfd_macro=yes, | |
36 | gl_cv_func_dirfd_macro=no)]) | |
37 | ||
49e4877c PA |
38 | # Use the replacement if we have no function or macro with that name, |
39 | # or if OS/2 kLIBC whose dirfd() does not work. | |
40 | # Replace only if the system declares dirfd already. | |
41 | case $ac_cv_func_dirfd,$gl_cv_func_dirfd_macro,$host_os,$ac_cv_have_decl_dirfd in | |
42 | no,no,*,yes | *,*,os2*,yes) | |
18848e28 | 43 | REPLACE_DIRFD=1 |
49e4877c PA |
44 | AC_DEFINE([REPLACE_DIRFD], [1], |
45 | [Define to 1 if gnulib's dirfd() replacement is used.]);; | |
46 | esac | |
18848e28 GF |
47 | ]) |
48 | ||
49 | dnl Prerequisites of lib/dirfd.c. | |
50 | AC_DEFUN([gl_PREREQ_DIRFD], | |
51 | [ | |
52 | AC_CACHE_CHECK([how to get the file descriptor associated with an open DIR*], | |
53 | [gl_cv_sys_dir_fd_member_name], | |
54 | [ | |
55 | dirfd_save_CFLAGS=$CFLAGS | |
56 | for ac_expr in d_fd dd_fd; do | |
57 | ||
58 | CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr" | |
59 | AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ | |
60 | #include <sys/types.h> | |
61 | #include <dirent.h>]], | |
62 | [[DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;]])], | |
63 | [dir_fd_found=yes] | |
64 | ) | |
65 | CFLAGS=$dirfd_save_CFLAGS | |
66 | test "$dir_fd_found" = yes && break | |
67 | done | |
68 | test "$dir_fd_found" = yes || ac_expr=no_such_member | |
69 | ||
70 | gl_cv_sys_dir_fd_member_name=$ac_expr | |
71 | ] | |
72 | ) | |
73 | if test $gl_cv_sys_dir_fd_member_name != no_such_member; then | |
74 | AC_DEFINE_UNQUOTED([DIR_FD_MEMBER_NAME], | |
75 | [$gl_cv_sys_dir_fd_member_name], | |
76 | [the name of the file descriptor member of DIR]) | |
77 | fi | |
78 | AH_VERBATIM([DIR_TO_FD], | |
79 | [#ifdef DIR_FD_MEMBER_NAME | |
80 | # define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME) | |
81 | #else | |
82 | # define DIR_TO_FD(Dir_p) -1 | |
83 | #endif | |
84 | ]) | |
85 | ]) |