Must one include all “file.o” files where there is “#include ”file.h“ ”

Question

I have massive cross compilation of omxplayer whcih I am trying to debug. The file is downloaded from here. Unfortunately there are over 5000 files so I can not upload the directory tree. Here is the make command that gets issued:

/path/to/cross/compiler/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-g++ --sysroot=/mnt/root -Wall -L/mnt/root/lib -L/mnt/root/lib -L/mnt/root/usr/lib -L/mnt/root/usr/lib/omxplayer -L/mnt/root/opt/vc/lib -L/mnt/root/usr/lib/arm-linux-gnueabihf -L./ -ldbus-1 -lc -lWFC -lGLESv2 -lEGL -lbcm_host -lopenmaxil -lfreetype -lz -Lffmpeg_compiled/usr/local/lib/ -o omxplayer.bin linux/XMemUtils.o utils/log.o DynamicDll.o utils/PCMRemap.o utils/RegExp.o OMXSubtitleTagSami.o OMXOverlayCodecText.o BitstreamConverter.o linux/RBP.o OMXThread.o OMXReader.o OMXStreamInfo.o OMXAudioCodecOMX.o OMXCore.o OMXVideo.o OMXAudio.o OMXClock.o File.o OMXPlayerVideo.o OMXPlayerAudio.o OMXPlayerSubtitles.o SubtitleRenderer.o Unicode.o Srt.o KeyConfig.o OMXControl.o Keyboard.o omxplayer.o -lvchiq_arm -lvcos -lrt -lpthread -lavutil -lavcodec -lavformat -lavdevice -lavfilter -lswscale -lswresample -lpcre ./arm-linux-gnueabihf-pkg-config --libs dbus-1 -lrt

But then I get the following errors:

/path/to/cross/compiler/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/../lib/gcc/arm-linux-gnueabihf/4.7.2/../../../../arm-linux-gnueabihf/bin/ld: warning: libavutil.so.51, needed by /mnt/root/usr/lib/arm-linux-gnueabihf/libpostproc.so.52, may conflict with libavutil.so.52
BitstreamConverter.o: In function `DllAvUtilBase::av_frame_move_ref(AVFrame*, AVFrame*)':
BitstreamConverter.cpp:(.text._ZN13DllAvUtilBase17av_frame_move_refEP7AVFrameS1_[_ZN13DllAvUtilBase17av_frame_move_refEP7AVFrameS1_]+0x8): undefined reference to `av_frame_move_ref'
BitstreamConverter.o: In function `DllAvUtilBase::av_frame_unref(AVFrame*)':
BitstreamConverter.cpp:(.text._ZN13DllAvUtilBase14av_frame_unrefEP7AVFrame[_ZN13DllAvUtilBase14av_frame_unrefEP7AVFrame]+0x4): undefined reference to `av_frame_unref'
BitstreamConverter.o: In function `DllAvUtilBase::av_frame_alloc()':
BitstreamConverter.cpp:(.text._ZN13DllAvUtilBase14av_frame_allocEv[_ZN13DllAvUtilBase14av_frame_allocEv]+0x0): undefined reference to `av_frame_alloc'
BitstreamConverter.o: In function `DllAvUtilBase::av_frame_free(AVFrame**)':
BitstreamConverter.cpp:(.text._ZN13DllAvUtilBase13av_frame_freeEPP7AVFrame[_ZN13DllAvUtilBase13av_frame_freeEPP7AVFrame]+0x4): undefined reference to `av_frame_free'
collect2: error: ld returned 1 exit status
make: *** [omxplayer.bin] Error 1

I traced the av_frame_unref function and the others to frame.h which is in both ffmpeg_compiled/usr/local/include/libavutil/frame.h and ffmpeg/libavutil/frame.h. Normally I would link to the .so library with -lframe or -Lffmpeg/libavutil/ -lframe, however, this is not a shared library (.so file) but an object file (.o file). I am pretty sure I do not have to link these manually, that's what the make file is for. Anyone shed some light on what is going on. Also, I will include my Makefile below (I also have a Makefile.include showing the cross compile options, I can post that as well if necessary)

Makefile:

SRC=linux/XMemUtils.cpp \
        utils/log.cpp \
        DynamicDll.cpp \
        utils/PCMRemap.cpp \
        utils/RegExp.cpp \
        OMXSubtitleTagSami.cpp \
        OMXOverlayCodecText.cpp \
        BitstreamConverter.cpp \
        linux/RBP.cpp \
        OMXThread.cpp \
        OMXReader.cpp \
        OMXStreamInfo.cpp \
        OMXAudioCodecOMX.cpp \
        OMXCore.cpp \
        OMXVideo.cpp \
        OMXAudio.cpp \
        OMXClock.cpp \
        File.cpp \
        OMXPlayerVideo.cpp \
        OMXPlayerAudio.cpp \
        OMXPlayerSubtitles.cpp \
        SubtitleRenderer.cpp \
        Unicode.cpp \
        Srt.cpp \
        KeyConfig.cpp \
        OMXControl.cpp \
        Keyboard.cpp \
        omxplayer.cpp \

OBJS+=$(filter %.o,$(SRC:.cpp=.o))

all: omxplayer.bin

%.o: %.cpp
    @rm -f $@ 
    $(CXX) $(CFLAGS) $(INCLUDES) -c $< -o $@ -Wno-deprecated-declarations

version:
    bash gen_version.sh > version.h 

omxplayer.bin: version $(OBJS)
    $(CXX) $(LDFLAGS) -o omxplayer.bin $(OBJS) -lvchiq_arm -lvcos -lrt -lpthread -lavutil -lavcodec -lavformat -lavdevice -lavfilter -lswscale -lswresample -lpcre `./arm-linux-gnueabihf-pkg-config --libs dbus-1` -lrt
    #arm-unknown-linux-gnueabi-strip omxplayer.bin

clean:
    for i in $(OBJS); do (if test -e "$$i"; then ( rm $$i ); fi ); done
    @rm -f omxplayer.old.log omxplayer.log
    @rm -f omxplayer.bin
    @rm -rf $(DIST)
    @rm -f omxplayer-dist.tar.gz

ffmpeg:
    @rm -rf ffmpeg
    make -f Makefile.ffmpeg
    make -f Makefile.ffmpeg install

dist: omxplayer.bin
    mkdir -p $(DIST)/usr/lib/omxplayer
    mkdir -p $(DIST)/usr/bin
    mkdir -p $(DIST)/usr/share/doc
    cp omxplayer omxplayer.bin $(DIST)/usr/bin
    cp COPYING $(DIST)/usr/share/doc/
    cp README.md $(DIST)/usr/share/doc/README
    cp -a ffmpeg_compiled/usr/local/lib/*.so* $(DIST)/usr/lib/omxplayer/
    tar -czf omxplayer-dist.tar.gz $(DIST)

@Beta both are identical, and both have the header file which has the signature for av_frame_move_ref but only ffmpeg/libavutil/ has frame.o and frame.c — puk

Homer6 Homer6 · Accepted Answer · 2013-12-03T00:40:07

It looks like you need to pull in the function definition from the .o files at compile time. I found this article very helpful in explaining the theory behind this:

http://eli.thegreenplace.net/2013/07/09/library-order-in-static-linking/

For more information on linking and compiling, I also highly recommend this book: http://www.network-theory.co.uk/docs/gccintro/index.html

Must one include all “file.o” files where there is “#include ”file.h“ ”

2 Answers