[Ffmpeg-devel] [PATCH] Cygwin vhook, always static avformat

[Víctor Paesa]

Hi,
>
>> Does just adding
>>
>>   VHOOKFLAGS="-shared"
>>
>> and removing vhook=no from the Cygwin section help already?
>
>
> I made your suggested changes, then
> "./configure --enable-static- --disable-shared; make",
> and I got this error:
>
> gcc -fPIC -O3  -g -Wdeclaration-after-statement -Wall -Wno-switch -I..
> -I/home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg
> -I/home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/libavformat
> -I/home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/libavcodec
> -I/home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/libavutil
> -DHAVE_AV_CONFIG_H
> `freetype-config --cflags`   -c -o null.o null.c
> null.c:1: warning: -fPIC ignored for target (all code is position
> independent)
> gcc -Wl,--warn-common   -rdynamic -export-dynamic -Wl,--as-needed
> -Wl,-rpath-link,/home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/libavcodec
> -Wl,-rpath-link,/home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/libavformat
> -Wl,-rpath-link,/home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/libavutil
> -lImlib2 `freetype-config --libs` -g -o null.dll -shared null.o
> gcc: unrecognized option `-rdynamic'
> null.o: In function `Configure':
> /home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/vhook/null.c:40: undefined
> reference to `_av_mallocz'
> null.o: In function `Process':
> /home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/vhook/null.c:56: undefined
> reference to `_avpicture_get_size'
> /home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/vhook/null.c:57: undefined
> reference to `_av_malloc'
> /home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/vhook/null.c:59: undefined
> reference to `_avpicture_fill'
> /home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/vhook/null.c:60: undefined
> reference to `_img_convert'
> /home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/vhook/null.c:71: undefined
> reference to `_img_convert'
> /home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/vhook/null.c:76: undefined
> reference to `_av_free'
> null.o: In function `Release':
> /home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/vhook/null.c:33: undefined
> reference to `_av_free'
> collect2: ld returned 1 exit status
> make[1]: *** [null.dll] Error 1
> rm null.o
> make[1]: Leaving directory
> `/home/wzrlpy/src/FFMpeg-20060729-5847/ffmpeg/vhook'
> make: *** [videohook] Error 2
>
> The errors are the same after
> "make distclean; ./configure --enable-shared --disable-static; make".
>
> The reason is that WIN32 does not allow undefined symbols during linking.
>
> These symbols might be defined by:
>
> a) Adding the av[ucf]* libraries as VHOOKLIBS (the
> ffmpeg.cygwin.vhook.6.patch way)
>
> b) Creating a .def for the _av_mallocz, _avpicture_get_size, etc. that
> exist in ffmpeg.exe (static build), then adding
> that .def to the linking steps in vhooks.
>
> c) Using __declspec(dllimport) (a.ka. FF_IMPORT_ATTR) somehow, somewhere
> in vhooks (shared libraries builds).
>
> I believe that (a) is the solution that minimizes changes and is more
> portable.
>
> I applied the changes to SVN-5847, but the changes to the build system in
> r5860, r5862, r5869, r5872, r5874, r5875, r5882, r5884
> are not adding libraries to the vhook subsystem, so I believe it won't
> make
> a difference if I apply it to current SVN.
>
> I will rebase to current SVN this evening and I will confirm it.
>
Confirmed, I get the same "undefined reference to `_av_mallocz'" errors
in vhooks after rebasing to SVN-5893 and having applied this patch:

diff -Naur ffmpeg-old/configure ffmpeg/configure
--- ffmpeg-old/configure        2006-08-02 18:35:51.000000000 +0200
+++ ffmpeg/configure    2006-08-02 19:04:56.078125000 +0200
@@ -591,7 +591,7 @@
 v4l2="no"
 audio_oss="yes"
 dv1394="no"
-vhook="no"
+VHOOKFLAGS='-shared'
 extralibs=""
 EXESUF=".exe"
 SLIBPREF="cyg"


Regards,
V?ctor Paesa