On Thu, 2016-11-10 at 18:52 +0100, Mark Wielaard wrote:
> GCC7 adds warnings for snprintf formatting into too small buffers.
> Fix the two issues pointed out by the new warning. The ar header
> fields are fixed length containing left-justified strings without
> zero terminator. snprintf always adds a '\0' char at the end (which
> we then don't copy into the ar header field) and numbers are decimal
> strings of fixed 10 chars  (-Wformat-length thinks formatting
> them as size_t might overflow on 64bit arches).

That fix was slightly wrong. The numbers should be formatted as unsigned
decimals. And I wasn't passing in the right type. GCC7 missed my
mistakes, but older GCC versions caught it. I filed a bug:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78304

Attached the corrected version of the patch that is -Wformat warning
free on all versions.

Cheers,

Mark