Re: [PATCH 0/2] fix status_printf_ln calls "zero-length format" warnings

[Jeff King <peff@peff.net>]

On Mon, Mar 10, 2014 at 08:27:25PM +0100, Benoit Pierre wrote:

> Those happens with "gcc -Wformat-zero-length". Since passing NULL does not
> generate a warning (as __attribute__((printf())) does not imply nonull), modify
> status_printf/status_printf_ln to allow a NULL format and update calls with an
> empty string.

Most of us who compile with -Wall decided a while ago to use
-Wno-format-zero-length, because it really is a silly complaint (it
assumes there are no side effects of the function besides printing the
format string, which is obviously not true in this case).

It would be nice to compile out of the box with "-Wall -Werror", and I
think your solution looks relatively clean. But I am slightly concerned
about the assumption that it is OK to pass a NULL fmt parameter to a
function marked with __attribute__((format)).  It certainly seems to be
the case now, and I do not know of any plans for that to change, but it
seems like a potentially obvious thing for the compiler to check.

I dunno; perhaps it has already been considered and rejected by gcc
folks to allow the exact escape hatch we are using here.

-Peff