--- a/doc/gnulib.texi
+++ b/doc/gnulib.texi
@@ -5746,6 +5746,7 @@
 * gcd::
 * Regular expressions::
 * Supporting Relocation::
+* __func__::
 @end menu
 
 @node alloca
@@ -5825,6 +5826,19 @@
 
 @include regexprops-generic.texi
 
+@node __func__
+@section __func__
+
+The @code{__func__} module makes sure that you can use the
+@code{__func__} variable as defined by C99 in your code.
+
+A small example is:
+
+@smallexample
+#include <config.h>
+...
+printf ("%s: something happened\n", __func__);
+@end smallexample
 
 @node GNU Free Documentation License
 @appendix GNU Free Documentation License

new file mode 100644
--- /dev/null
+++ b/m4/__func__.m4
@@ -0,0 +1,20 @@
+# __func__.m4 serial 1
+dnl Copyright (C) 2008 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.
+
+# Written by Simon Josefsson
+
+AC_DEFUN([gl___FUNC__],
+[
+  AC_CACHE_CHECK([whether __func__ is available], [gl_cv_var___func__],
+     AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[]], [[const char *str = __func__;]])],
+       [gl_cv_var___func__=yes],
+       [gl_cv_var___func__=no]))
+  if test "$gl_cv_var___func__" != yes; then
+    AC_DEFINE([__func__], ["<unknown function>"],
+              [Define as a replacement for the ISO C99 __func__ variable.])
+  fi
+])

new file mode 100644
--- /dev/null
+++ b/modules/__func__
@@ -0,0 +1,20 @@
+Description:
+Make sure __func__ is usable even on non-C99 platforms.
+
+Files:
+m4/__func__.m4
+
+Depends-on:
+
+configure.ac:
+gl___FUNC__
+
+Makefile.am:
+
+Include:
+
+License:
+LGPL
+
+Maintainer:
+Simon Josefsson

new file mode 100644
--- /dev/null
+++ b/modules/__func__-tests
@@ -0,0 +1,8 @@
+Files:
+tests/test-__func__.c
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-__func__
+check_PROGRAMS += test-__func__

new file mode 100644
--- /dev/null
+++ b/tests/test-__func__.c
@@ -0,0 +1,41 @@
+/* Test whether __func__ is available
+   Copyright (C) 2008 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   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.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2008.  */
+
+#include <config.h>
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define ASSERT(expr)							\
+  do									\
+    {									\
+      if (!(expr))							\
+	{								\
+	  fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+	  abort ();							\
+	}								\
+    }									\
+  while (0)
+
+int
+main ()
+{
+  ASSERT (strlen (__func__) + 1 == sizeof (__func__));
+  return 0;
+}