regex.m4: correct the reversed range endpoint ([b-a]) test

[gnulib.git] / m4 / regex.m4

diff --git a/m4/regex.m4 b/m4/regex.m4
index 4e24b84..95784e4 100644 (file)
--- a/m4/regex.m4
+++ b/m4/regex.m4
@@ -1,7 +1,7 @@
-# serial 55
+# serial 56
 
-# Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005,
-# 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+# Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006,
+# 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -96,6 +96,14 @@ AC_DEFUN([gl_REGEX],
             if (!s)
               return 1;
 
+            /* Ensure that [b-a] is diagnosed as invalid, when
+               using RE_NO_EMPTY_RANGES. */
+            re_set_syntax (RE_SYNTAX_POSIX_EGREP | RE_NO_EMPTY_RANGES);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("a[b-a]", 6, &regex);
+            if (s == 0)
+              return 1;
+
             /* This should succeed, but does not for glibc-2.1.3.  */
             memset (&regex, 0, sizeof regex);
             s = re_compile_pattern ("{1", 2, &regex);