[Qemu-devel] [PATCH for 1.7] qobject: Fix compiler warning (missing gnu_printf format attribute)

[Qemu-devel] [PATCH for 1.7] qobject: Fix compiler warning (missing gnu_printf format attribute)

[Stefan Weil]

gcc 4.8.2 reports this warning when extra warnings are enabled (-Wextra):

  CC    qobject/qerror.o
qobject/qerror.c: In function ‘qerror_from_info’:
qobject/qerror.c:53:5: error:
 function might be possible candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
     qerr->err_msg = g_strdup_vprintf(fmt, *va);
     ^

Signed-off-by: Stefan Weil <sw@weilnetz.de>
---

Note: checkpatch.pl wrongly reports an error.

 qobject/qerror.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/qobject/qerror.c b/qobject/qerror.c
index 3aee1cf..fc8331a 100644
--- a/qobject/qerror.c
+++ b/qobject/qerror.c
@@ -42,8 +42,8 @@ static QError *qerror_new(void)
  *
  * Return strong reference.
  */
-static QError *qerror_from_info(ErrorClass err_class, const char *fmt,
-                                va_list *va)
+static QError * GCC_FMT_ATTR(2, 0)
+qerror_from_info(ErrorClass err_class, const char *fmt, va_list *va)
 {
     QError *qerr;
 
-- 
1.7.10.4

Re: [Qemu-devel] [Qemu-trivial] [PATCH for 1.7] qobject: Fix compiler warning (missing gnu_printf format attribute)

[Michael Tokarev]

17.11.2013 22:00, Stefan Weil wrote:
> gcc 4.8.2 reports this warning when extra warnings are enabled (-Wextra):
> 
>   CC    qobject/qerror.o
> qobject/qerror.c: In function ‘qerror_from_info’:
> qobject/qerror.c:53:5: error:
>  function might be possible candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
>      qerr->err_msg = g_strdup_vprintf(fmt, *va);
>      ^

Thanks, applied to the trivial-patches queue.  Hopefully we found and verified
all invlcations of qerror_from_info() and there really are no "wrong" invocations
which will lead to new warnings after this printf attribute addition... ;)

(This function is static so only this file needed to be checked).

/mjt