[systemd-devel] [systemd-commits] configure.ac

[David Herrmann]

Hi

On Tue, Feb 24, 2015 at 4:07 PM, Zbigniew Jędrzejewski-Szmek
<zbyszek at in.waw.pl> wrote:
> On Tue, Feb 24, 2015 at 07:02:49AM -0800, David Herrmann wrote:
>>  configure.ac |    1 +
>>  1 file changed, 1 insertion(+)
>>
>> New commits:
>> commit 0a98d66159e474915afd6597d3aa444a698fdd2d
>> Author: David Herrmann <dh.herrmann at gmail.com>
>> Date:   Tue Feb 24 15:59:06 2015 +0100
>>
>>     build: add -Wno-format-signedness
>>
>>     gcc5 introduced this option (gcc4 silently ignores it, which is fine).
>>     Given that gcc5 thinks 'unsigned char'/'unsigned short' is promoted to
>>     'int' for var-args, stuff like this spits out warnings:
>>         uint8_t x;
>>         printf("%" PRIu8", x);
>>
>>     gcc5 promots 'x' to 'int', instead of 'unsigned int' and thus gets a
>>     signedness-warnings as it expects an 'unsigned int'.
>>
>>     glibc states otherwise: unsigneds are always promoted to 'unsigned int'.
>>     Until gcc and glibc figure this out, lets just ignore that warning (which
>>     is totally useless in its current form).
>>
>> diff --git a/configure.ac b/configure.ac
>> index 9a2235b..22a6f17 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -186,6 +186,7 @@ CC_CHECK_FLAGS_APPEND([with_cflags], [CFLAGS], [\
>>          -Wno-unused-parameter \
>>          -Wno-missing-field-initializers \
>>          -Wno-unused-result \
>> +        -Wno-format-signedness \
> This doesn't really work, as discussed previously on the list.

Why? Works fine with gcc4 and gcc5 here. What's the problem exactly?

Thanks
David