c/6547: misleading printf '$' format

[Joseph S. Myers]

On Fri, 3 May 2002, Pierre-Canalsat PETIT wrote:

> int main(int argc, char *argv[]) {
>   printf("Usage: %1$s [-n <option 1>] [-m <option 2>]\n"
>        "       %3$*2$c [-i <input>] [-o <output>] [-c <nb>] [-t <ms>]\n"
>        "       %3$*2$c <file.in> <file.out>\n", *argv, strlen(*argv), ' ');
>   return 0;
> }
> 
> This returns me a "warning: too few arguments for format".
> But if you remove the second line of the format, it does compile
> without warning...

Thanks for that bug report.  Patch below applied to mainline only
(since it's not a regression).  Bootstrapped with no regressions on
i686-pc-linux-gnu.

2002-05-03  Joseph S. Myers  <jsm28@cam.ac.uk>

	* c-format.c (check_format_info_main): Don't check for presence of
	parameter for * width until after operand number has been read,
	and only check for it if format parameters are available.
	Fixes PR c/6547.

testsuite:
2002-05-03  Joseph S. Myers  <jsm28@cam.ac.uk>

	* gcc.dg/format/xopen-2.c: New test.

--- c-format.c.orig	2002-04-19 19:10:11.000000000 +0000
+++ c-format.c	2002-05-03 15:01:13.000000000 +0000
@@ -1751,11 +1751,6 @@ check_format_info_main (status, res, inf
 	      /* "...a field width...may be indicated by an asterisk.
 		 In this case, an int argument supplies the field width..."  */
 	      ++format_chars;
-	      if (params == 0)
-		{
-		  status_warning (status, "too few arguments for format");
-		  return;
-		}
 	      if (has_operand_number != 0)
 		{
 		  int opnum;
@@ -1775,6 +1770,11 @@ check_format_info_main (status, res, inf
 		}
 	      if (info->first_arg_num != 0)
 		{
+		  if (params == 0)
+		    {
+		      status_warning (status, "too few arguments for format");
+		      return;
+		    }
 		  cur_param = TREE_VALUE (params);
 		  if (has_operand_number <= 0)
 		    {
--- testsuite/gcc.dg/format/xopen-2.c	2001-03-26 23:57:02.000000000 +0000
+++ testsuite/gcc.dg/format/xopen-2.c	2002-05-03 14:59:20.000000000 +0000
@@ -0,0 +1,21 @@
+/* Test for X/Open format extensions, as found in the
+   Single Unix Specification.  Test for bug reported by
+   Pierre-Canalsat PETIT <pierrecanalsat.petit.canalsat@canal-plus.com>
+   in PR c/6547.  The test for absence of a parameter for a * width was done
+   too early in the case of operand numbers and vprintf formats.
+*/
+/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wformat" } */
+
+#include "format.h"
+
+void vbar (va_list, const char *) __attribute__((__format__(__printf__, 2, 0)));
+
+void
+foo (int i, int j, va_list va)
+{
+  printf("%2$*1$c", i, j);
+  printf("%2$*1$c %2$*1$c", i, j); /* { dg-bogus "too few" "bogus too few dollar" } */
+  vbar(va, "%*s"); /* { dg-bogus "too few" "bogus too few vprintf" } */
+}

-- 
Joseph S. Myers
jsm28@cam.ac.uk