2 dnl Run a program to determine whether whether link(2) follows symlinks.
3 dnl Set LINK_FOLLOWS_SYMLINKS accordingly.
5 # Copyright (C) 1999, 2000, 2001, 2004 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.
10 AC_DEFUN([gl_AC_FUNC_LINK_FOLLOWS_SYMLINK],
13 [whether link(2) dereferences a symlink specified with a trailing slash],
14 jm_ac_cv_func_link_follows_symlink,
16 dnl poor-man's AC_REQUIRE: FIXME: repair this once autoconf-3 provides
17 dnl the appropriate framework.
18 test -z "$ac_cv_header_unistd_h" \
19 && AC_CHECK_HEADERS(unistd.h)
21 # Create a regular file.
25 # include <sys/types.h>
26 # include <sys/stat.h>
31 # define SAME_INODE(Stat_buf_1, Stat_buf_2) \
32 ((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \
33 && (Stat_buf_1).st_dev == (Stat_buf_2).st_dev)
38 const char *file = "conftest.file";
39 const char *sym = "conftest.sym";
40 const char *hard = "conftest.hard";
41 struct stat sb_file, sb_hard;
43 /* Create a symlink to the regular file. */
44 if (symlink (file, sym))
47 /* Create a hard link to that symlink. */
51 if (lstat (hard, &sb_hard))
53 if (lstat (file, &sb_file))
56 /* If the dev/inode of hard and file are the same, then
57 the link call followed the symlink. */
58 return SAME_INODE (sb_hard, sb_file) ? 0 : 1;
61 jm_ac_cv_func_link_follows_symlink=yes,
62 jm_ac_cv_func_link_follows_symlink=no,
63 jm_ac_cv_func_link_follows_symlink=yes dnl We're cross compiling.
66 if test $jm_ac_cv_func_link_follows_symlink = yes; then
67 AC_DEFINE(LINK_FOLLOWS_SYMLINKS, 1,
68 [Define if `link(2)' dereferences symbolic links.])