[FFmpeg-devel] Fix libx264

Måns Rullgård mans
Thu Feb 4 10:24:32 CET 2010

Ramiro Polla <ramiro.polla at gmail.com> writes:

> 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
> libraries:
> [...]
> -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.

Your opinion is irrelevant.  We support some systems where this simply
doesn't work.

M?ns Rullg?rd
mans at mansr.com

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