-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
+AC_DEFUN([gl_FUNC_GETCWD_NULL],
+ [
+ AC_CACHE_CHECK([whether getcwd (NULL, 0) allocates memory for result],
+ [gl_cv_func_getcwd_null],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+# include <unistd.h>
+# ifndef getcwd
+ char *getcwd ();
+# endif
+]], [[
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+/* mingw cwd does not start with '/', but getcwd does allocate. */
+#else
+ if (chdir ("/") != 0)
+ return 1;
+ else
+ {
+ char *f = getcwd (NULL, 0);
+ return ! (f && f[0] == '/' && !f[1]);
+ }
+#endif
+ ]])],
+ [gl_cv_func_getcwd_null=yes],
+ [gl_cv_func_getcwd_null=no],
+ [[
+ case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_getcwd_null="guessing yes";;
+ # Guess yes on Cygwin.
+ cygwin*) gl_cv_func_getcwd_null="guessing yes";;
+ # Guess yes on mingw.
+ mingw*) gl_cv_func_getcwd_null="guessing yes";;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_getcwd_null="guessing no";;
+ esac
+ ]])])
+])