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#serial 3
dnl Run a program to determine whether whether link(2) follows symlinks.
dnl Set LINK_FOLLOWS_SYMLINKS accordingly.
AC_DEFUN([jm_AC_FUNC_LINK_FOLLOWS_SYMLINK],
[dnl
AC_CACHE_CHECK(
[whether link(2) dereferences a symlink specified with a trailing slash],
jm_ac_cv_func_link_follows_symlink,
[
dnl poor-man's AC_REQUIRE: FIXME: repair this once autoconf-3 provides
dnl the appropriate framework.
test -z "$ac_cv_header_unistd_h" \
&& AC_CHECK_HEADERS(unistd.h)
# Create a regular file.
echo > conftest.file
AC_TRY_RUN(
[
# include <sys/types.h>
# include <sys/stat.h>
# ifdef HAVE_UNISTD_H
# include <unistd.h>
# endif
# define SAME_INODE(Stat_buf_1, Stat_buf_2) \
((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \
&& (Stat_buf_1).st_dev == (Stat_buf_2).st_dev)
int
main ()
{
const char *file = "conftest.file";
const char *sym = "conftest.sym";
const char *hard = "conftest.hard";
struct stat sb_file, sb_hard;
/* Create a symlink to the regular file. */
if (symlink (file, sym))
abort ();
/* Create a hard link to that symlink. */
if (link (sym, hard))
abort ();
if (lstat (hard, &sb_hard))
abort ();
if (lstat (file, &sb_file))
abort ();
/* If the dev/inode of hard and file are the same, then
the link call followed the symlink. */
return SAME_INODE (sb_hard, sb_file) ? 0 : 1;
}
],
jm_ac_cv_func_link_follows_symlink=yes,
jm_ac_cv_func_link_follows_symlink=no,
jm_ac_cv_func_link_follows_symlink=yes dnl We're cross compiling.
)
])
if test $jm_ac_cv_func_link_follows_symlink = yes; then
AC_DEFINE(LINK_FOLLOWS_SYMLINKS, 1,
[Define if `link(2)' dereferences symbolic links.])
fi
])
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