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Re: c/6547: misleading printf '$' format
- From: "Joseph S. Myers" <jsm28 at cam dot ac dot uk>
- To: nobody at gcc dot gnu dot org
- Cc: gcc-prs at gcc dot gnu dot org,
- Date: 3 May 2002 20:26:03 -0000
- Subject: Re: c/6547: misleading printf '$' format
- Reply-to: "Joseph S. Myers" <jsm28 at cam dot ac dot uk>
The following reply was made to PR c/6547; it has been noted by GNATS.
From: "Joseph S. Myers" <jsm28@cam.ac.uk>
To: Pierre-Canalsat PETIT <pierrecanalsat.petit.canalsat@canal-plus.com>
Cc: <gcc-bugs@gcc.gnu.org>, <gcc-gnats@gcc.gnu.org>,
<gcc-patches@gcc.gnu.org>, <peio@blutch.dyndns.org>,
<prpetit@canal-plus.com>
Subject: Re: c/6547: misleading printf '$' format
Date: Fri, 3 May 2002 21:19:08 +0100 (BST)
On Fri, 3 May 2002, Pierre-Canalsat PETIT wrote:
> int main(int argc, char *argv[]) {
> printf("Usage: %1$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