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18848e28 GF |
1 | # serial 22 -*- Autoconf -*- |
2 | ||
3 | dnl Find out how to get the file descriptor associated with an open DIR*. | |
4 | ||
4a626d0a | 5 | # Copyright (C) 2001-2006, 2008-2015 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 | ||
38 | # Use the replacement only if we have no function or macro with that name. | |
39 | if test $ac_cv_func_dirfd = no && test $gl_cv_func_dirfd_macro = no; then | |
40 | if test $ac_cv_have_decl_dirfd = yes; then | |
41 | # If the system declares dirfd already, let's declare rpl_dirfd instead. | |
42 | REPLACE_DIRFD=1 | |
43 | fi | |
44 | fi | |
45 | ]) | |
46 | ||
47 | dnl Prerequisites of lib/dirfd.c. | |
48 | AC_DEFUN([gl_PREREQ_DIRFD], | |
49 | [ | |
50 | AC_CACHE_CHECK([how to get the file descriptor associated with an open DIR*], | |
51 | [gl_cv_sys_dir_fd_member_name], | |
52 | [ | |
53 | dirfd_save_CFLAGS=$CFLAGS | |
54 | for ac_expr in d_fd dd_fd; do | |
55 | ||
56 | CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr" | |
57 | AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ | |
58 | #include <sys/types.h> | |
59 | #include <dirent.h>]], | |
60 | [[DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;]])], | |
61 | [dir_fd_found=yes] | |
62 | ) | |
63 | CFLAGS=$dirfd_save_CFLAGS | |
64 | test "$dir_fd_found" = yes && break | |
65 | done | |
66 | test "$dir_fd_found" = yes || ac_expr=no_such_member | |
67 | ||
68 | gl_cv_sys_dir_fd_member_name=$ac_expr | |
69 | ] | |
70 | ) | |
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]) | |
75 | fi | |
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) | |
79 | #else | |
80 | # define DIR_TO_FD(Dir_p) -1 | |
81 | #endif | |
82 | ]) | |
83 | ]) |