Re: [Mingw-w64-public] ffmpeg.c:4492: undefined reference to `_avdevice_register_all'

[Kai T. <kti...@go...>]

2011/9/10 Kyle <ksh...@gm...>:
> On 9/10/2011 6:52 AM, PcX wrote:
>
> 于 2011/9/10 18:51, PcX 写道:
>
> i686-w64-mingw32-gcc -Wl,--as-needed -Wl,--warn-common
> -Wl,-rpath-link=libpostproc:libswscale:libavfilter:libavdevice:libavformat:libavcodec:libavutil
> -o ffmpeg_g.exe ffmpeg.o cmdutils.o -Wl,--start-group
> -Llibavcodec -Llibavdevice -Llibavfilter
> -Llibavformat -Llibavutil -Llibpostproc -Llibswscale
> -L/home/kyle/software/ffmpeg/packages/sdl/sdl-1.2.14-win32/lib
>  -lavfilter -lavformat -lavcodec
> -lpostproc -lswscale -lavutil -lavicap32 -lpsapi -lole32 -lstrmiids
> -luuid -lws2_32
> -L/home/kyle/software/ffmpeg/packages/sdl/sdl-1.2.14-win32/lib -lmingw32
> -lSDLmain -lSDL -lm -luser32 -lgdi32 -lwinmm -ldxguid -lm -lpthread
> -lpsapi -lavdevice
> -Wl,--end-group
>
> As is, adding -Wl,--start-group and -Wl,--end-group
>
> Trying that command gives the same error. I did however recheckout my source
> and checked if objdump could find it this time (I did a small modification I
> forgot about in an attempt to fix this).
>
> I'm not sure if this makes any difference, but the command
> i686-w64-mingw32-objdump -x "./libavdevice/avdevice.dll" | grep
> "avdevice_register_all" now reads:
> [ 49](sec  1)(fl 0x00)(ty  20)(scl   2) (nx 1) 0x000004c0
> _avdevice_register_all
>
> instead of:
> [ 187] avdevice_register_all
> [ 49](sec  1)(fl 0x00)(ty  20)(scl   2) (nx 1) 0x000004c0
> _avdevice_register_all
>
> I apologize for the mixup, that was my mistake.

Yes, this makes a difference.  As this means that this symbol isn't
exported from the DLL.  Means avdevice sources needs a
__declspec(dllexport) for the symbol avdevice_register_all.

Regards,
Kai