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# link.m4 serial 9
dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_LINK],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CHECK_FUNCS_ONCE([link])
if test $ac_cv_func_link = no; then
HAVE_LINK=0
else
AC_CACHE_CHECK([whether link obeys POSIX],
[gl_cv_func_link_works],
[touch conftest.a
# Assume that if we have lstat, we can also check symlinks.
if test $ac_cv_func_lstat = yes; then
ln -s conftest.a conftest.lnk
fi
AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
#include <stdio.h>
]],
[[int result = 0;
if (!link ("conftest.a", "conftest.b/"))
result |= 1;
#if HAVE_LSTAT
if (!link ("conftest.lnk/", "conftest.b"))
result |= 2;
if (rename ("conftest.a", "conftest.b"))
result |= 4;
if (!link ("conftest.b", "conftest.lnk"))
result |= 8;
#endif
return result;
]])],
[gl_cv_func_link_works=yes], [gl_cv_func_link_works=no],
[case "$host_os" in
# Guess yes on glibc systems.
*-gnu* | gnu*) gl_cv_func_link_works="guessing yes" ;;
# If we don't know, assume the worst.
*) gl_cv_func_link_works="guessing no" ;;
esac
])
rm -f conftest.a conftest.b conftest.lnk])
case "$gl_cv_func_link_works" in
*yes) ;;
*)
REPLACE_LINK=1
;;
esac
fi
])
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