[FFmpeg-devel] Fix libx264

Ramiro Polla ramiro.polla
Wed Feb 3 23:47:44 CET 2010

2010/2/3 M?ns Rullg?rd <mans at mansr.com>:
> Felipe Contreras <felipe.contreras at gmail.com> writes:
>> I'm getting this error when trying to build with --enable-libx264:
>> ---
>> gcc -o /tmp/ffconf.Ln1pzlRv /tmp/ffconf.PTBRiOvi.o -lz -lbz2 -lm
>> -lmp3lame -lm -lx264 -lm
>> /opt/x264/lib/libx264.a(encoder.o): In function `x264_encoder_frame_end':
>> encoder.c:(.text+0xe4a): undefined reference to `pthread_join'
>> Apparently this only happens when libx264 is built statically. In any
>> case, the solution is to add -lpthread.
> No, the correct solution is to add the compiler-specific flags
> required to link the thread library. ?For gcc this is -pthread, note
> no 'l', for other compilers it is often something else.

Hmm, according to [1]:
Standard Libraries

The c99 utility shall recognize the following -l operands for standard
-l pthread
    This operand shall make visible all functions referenced in
<pthread.h> and pthread_kill() and pthread_sigmask() referenced in
<signal.h>. An implementation may search this library in the absence
of this operand.

IMO the description for c99 in that page fits our use of gcc -std=c99.
So it seems pthread may actually be a library. In that case we should
support it. This means it should be put in the correct order so it may
be used by another library (in this case more specifically -lx264.

Ramiro Polla
[1] http://www.opengroup.org/onlinepubs/000095399/utilities/c99.html

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