* errfn.c (cp_thing): Handle the `%%' formatting sequence.

From-SVN: r20537

gcc/cp/ChangeLog

+1998-06-17  Mark Mitchell  <mark@markmitchell.com>
+
+	* errfn.c (cp_thing): Handle the `%%' formatting sequence.
+
 1998-06-17  Jason Merrill  <jason@yorick.cygnus.com>
 
 	* method.c (hack_identifier): Complain about getting a namespace

gcc/cp/errfn.c

@@ -50,7 +50,8 @@ extern int   cp_line_of PROTO((tree));
 
 #define STRDUP(f) (ap = (char *) alloca (strlen (f) +1), strcpy (ap, (f)), ap)
 
-/* This function supports only `%s', `%d', and the C++ print codes.  */
+/* This function supports only `%s', `%d', `%%', and the C++ print
+   codes.  */
 
 #ifdef __STDC__
 static void
@@ -152,6 +153,21 @@ cp_thing (errfn, atarg1, format, ap)
 	  strcpy (buf + offset, p);
 	  offset += plen;
 	}
+      else if (*f == '%')
+	{
+	  /* A `%%' has occurred in the input string.  Since the
+	     string we produce here will be passed to vprintf we must
+	     preserve both `%' characters.  */
+
+	  len += 2;
+	  if (len > buflen)
+	    {
+	      buflen = len;
+	      buf = xrealloc (buf, len);
+	    }
+	  strcpy (buf + offset, "%%");
+	  offset += 2;
+	}
       else
 	{
 	  if (*f != 'd')