FFMPEG ignores --enable-pic option

[orange-cpp]

When i build ffmpeg on arch linux using vcpkg install ffmpeg:x64-linux i got error from linker:

libswscale.a(swscale.o): warning: relocation againstff_M24B' in read-only section .text' /usr/bin/ld: ibavcodec.a(vc1dsp_mmx.o): relocation R_X86_64_PC32 against symbol ff_pw_9' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: bad value
`

But in vcpkg output --enable-pic is set by default.

How can i make FFMPEG link normaly in my .so program?

PS: I need to static linking of FFMPEG.

[WangWeiLin-MV]

Using the latest version of vcpkg for local installation does not reproduce the issue.

Would you please provide a repro step or commands? I've tried vcpkg install ffmpeg.

[orange-cpp]

Using the latest version of vcpkg for local installation does not reproduce the issue.

Would you please provide a repro step or commands? I've tried vcpkg install ffmpeg.

Did you try to link ffmpeg with your dynamic library not executable? it will fail compilation.

[orange-cpp]

Using the latest version of vcpkg for local installation does not reproduce the issue.

Would you please provide a repro step or commands? I've tried vcpkg install ffmpeg.

i meant ffpeg builds but it cant be linked

[WangWeiLin-MV]

The following usage test passes.

cmake_minimum_required(VERSION 3.25.1)
project(Test VERSION 0.1.2.3 LANGUAGES CXX)

add_executable(main c.cpp)
target_compile_features(main PRIVATE cxx_std_23)

find_package(FFMPEG REQUIRED)
target_include_directories(main PRIVATE ${FFMPEG_INCLUDE_DIRS})
target_link_directories(main PRIVATE ${FFMPEG_LIBRARY_DIRS})
target_link_libraries(main PRIVATE ${FFMPEG_LIBRARIES})

#ifdef __cplusplus
extern "C" {
#endif
#include "libavcodec/avcodec.h"
#include "libavutil/avutil.h"
#ifdef __cplusplus
}
#endif

#include <iostream>
int main() {

std::cout << "ffmpeg" << std::endl;
std::cout << av_version_info() << std::endl;

return 0;
}

i meant ffpeg builds but it cant be linked

Would you please provide a simple repro case?

[orange-cpp]

The following usage test passes.

cmake_minimum_required(VERSION 3.25.1)
project(Test VERSION 0.1.2.3 LANGUAGES CXX)

add_executable(main c.cpp)
target_compile_features(main PRIVATE cxx_std_23)

find_package(FFMPEG REQUIRED)
target_include_directories(main PRIVATE ${FFMPEG_INCLUDE_DIRS})
target_link_directories(main PRIVATE ${FFMPEG_LIBRARY_DIRS})
target_link_libraries(main PRIVATE ${FFMPEG_LIBRARIES})

#ifdef __cplusplus
extern "C" {
#endif
#include "libavcodec/avcodec.h"
#include "libavutil/avutil.h"
#ifdef __cplusplus
}
#endif

#include
int main() {

std::cout << "ffmpeg" << std::endl;
std::cout << av_version_info() << std::endl;

return 0;
}

i meant ffpeg builds but it cant be linked

Would you please provide a simple repro case?

no, use add_library(main MODULE c.cpp) and it will fail

[orange-cpp]

#ifdef __cplusplus
extern "C" {
#endif
#include "libavcodec/avcodec.h"
#include "libavutil/avutil.h"
#ifdef __cplusplus
}
#endif



#include <iostream>


__attribute__ ((visibility ("default"))) int main() {

    avcodec_find_encoder(AV_CODEC_ID_H264);
    std::cout << "ffmpeg" << std::endl;
    std::cout << av_version_info() << std::endl;

    return 0;
}

project(Test VERSION 0.1.2.3 LANGUAGES CXX)

add_library(main MODULE library.cpp)
target_compile_features(main PRIVATE cxx_std_23)

find_package(FFMPEG REQUIRED)
target_include_directories(main PRIVATE ${FFMPEG_INCLUDE_DIRS})
target_link_directories(main PRIVATE ${FFMPEG_LIBRARY_DIRS})
target_link_libraries(main PRIVATE ${FFMPEG_LIBRARIES})

Build log:

cmake --build /home/vlad/CLionProjects/untitled1/cmake-build/build/linux-release --target main -j 6
[2/2] Linking CXX shared module libmain.so
FAILED: libmain.so 
: && /usr/bin/g++ -fPIC -O3 -DNDEBUG  -Wl,--dependency-file=CMakeFiles/main.dir/link.d -shared  -o libmain.so CMakeFiles/main.dir/library.cpp.o -L/home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib   -L/home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/debug/lib -Wl,-rpath,/home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib:/home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/debug/lib  /home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib/libavdevice.a  /home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib/libavfilter.a  /home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib/libavformat.a  /home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib/libavcodec.a  /home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib/libswresample.a  /home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib/libswscale.a  /home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib/libavutil.a  -pthread  -lm  -latomic && :
/usr/bin/ld: /home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib/libavcodec.a(h264_intrapred_10bit.o): warning: relocation against `ff_pw_512' in read-only section `.text'
/usr/bin/ld: /home/vlad/CLionProjects/untitled1/extlibs/vcpkg/installed/x64-linux/lib/libavcodec.a(vc1dsp_mmx.o): relocation R_X86_64_PC32 against symbol `ff_pw_9' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: bad value
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

Repo with this sample: https://github.com/orange-cpp/ffpmeg-fpic-error-cmake