[FFmpeg-devel] [PATCH] Add -fno-common to PE32 CFLAGS

Baptiste Coudurier baptiste.coudurier
Mon Apr 13 22:31:51 CEST 2009

On 4/13/2009 12:48 PM, Baptiste Coudurier wrote:
> Hi Ramiro,
> On 4/8/2009 6:42 PM, Ramiro Polla wrote:
>> Hi,
>> Some time ago Art Clarke sent a patch to unconditionally add
>> -fno-common to mingw32 builds because of a bug in GCC. Instead of
>> applying the patch, the documentation was updated to reflect this bug
>> and the workaround.
>> The bug details can be found here:
>> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216
>> I finally took some time to investigate what combination of
>> gcc+binutils triggers the bug. Just like Brian Dessent mentions in
>> comment #6, the bug appears with binutils starting November 2007. The
>> gcc version doesn't matter as long as it puts data in .comm. binutils
>> 2.18 doesn't show this bug, but it has other shortcomings which make
>> it not fit for building FFmpeg.
>> With current mingw32 binutils floating around the web, all builds will
>> crash at some point in some optimizations (maybe Baptiste can give us
>> a sample that really crashes, I haven't seen them yet, but there are
>> lots of reports).
>> So is it ok to unconditionally include this flag with attached patch
>> (and a very descriptive log message) before binutils is fixed?
> Yes, please many bug reports on windows because of this, shared libs are
> just broken without it.
> You might remove it for OS/2 though according to Dave Yeo.

I think you could also only add it for shared libs. I don't recall it
was needed for static builds.

Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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