launchpad-users team mailing list archive

[Frank Trampe <frank.trampe@xxxxxxxxx>]

On Tue, Nov 19, 2013 at 8:04 PM, Andrew Kelley <superjoe30@xxxxxxxxx> wrote:

>
>
>
> On Tue, Nov 19, 2013 at 8:57 PM, Frank Trampe <frank.trampe@xxxxxxxxx>wrote:
>
>>
>>
>>
>> On Tue, Nov 19, 2013 at 7:31 PM, Andrew Kelley <superjoe30@xxxxxxxxx>wrote:
>>
>>>
>>> On Tue, Nov 19, 2013 at 7:34 PM, Frank Trampe <frank.trampe@xxxxxxxxx>wrote:
>>>
>>>> As you're running it, gcc is trying to link statically (against
>>>> libgroove.a), so the contents of libgroove.so don't mean much. Are you
>>>> trying to link dynamically?
>>>>
>>>
>>> Yes I am trying to link dynamically. I'm confused - I thought using -l
>>> was dynamic linking and specifying -static and supplying .a files does
>>> static linking.
>>>
>>
>> Most gcc installations on Linux try to link dynamically first if the
>> shared libraries are available and in the search path (I think) but will
>> fall back to static otherwise. Are you sure that the relevant so files are
>> in the search paths? Perhaps you could add the path manually via -L or
>> LIBRARY_PATH and see if that bypasses the problem.
>>
>
> Yes I am sure that the relevant .so files are in the search paths.
> libgroove.so should be the only necessary file. Observe:
>
> $ c99 -o test test.c
> /tmp/ccdS8adV.o: In function `main':
> test.c:(.text+0x41): undefined reference to `groove_init'
> test.c:(.text+0x46): undefined reference to `groove_finish'
> test.c:(.text+0x55): undefined reference to `groove_set_logging'
> test.c:(.text+0x5a): undefined reference to `groove_playlist_create'
> test.c:(.text+0x92): undefined reference to `groove_player_create'
> test.c:(.text+0xa9): undefined reference to `groove_player_attach'
> test.c:(.text+0xd9): undefined reference to `groove_file_open'
> (snip)
>
>
> $ c99 -o test test.c -lgroove
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o):
> In function `cleanup_save':
> (.text+0x29): undefined reference to `av_free_packet'
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o):
> In function `cleanup_save':
> (.text+0x39): undefined reference to `avio_closep'
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o):
> In function `cleanup_save':
> (.text+0x54): undefined reference to `avformat_free_context'
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o):
> In function `cleanup_save':
> (.text+0xa1): undefined reference to `av_log'
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o):
> In function `groove_file_close':
> (.text+0xe6): undefined reference to `av_free_packet'
> (snip)
>
>  The libav and SDL2 dependencies are internal to libgroove and should be
> completely hidden from the end-user of libgroove.
>
>
>> Either way, you will probably want to adjust the dependencies for the
>> package with the static library such that it pulls in the static libraries
>> for libsdl and libav at installation.
>>
>
> I agree that this is desirable. I searched for how to do this and the
> advice that I got was to not do it. Would you be willing to go more into
> detail about how to pull in static dependencies so that users who want to
> link statically against my library will not have to also link statically
> against my dependencies?
>
>
The standard solution isn't to statically link the symbols into your
libraries but to pull the -dev packages for libsdl and libav by adding them
as Requires entries for your -dev package. I think that the packages that
you need are libsdl-dev and libavutil-dev. These will in turn (via their
Require directives) automatically install the -dev packages necessary to
provide the static libraries that their static libraries need.


>>
>>> Furthermore, when I link the exact same test.c file with the same gcc
>>> args against a libgroove installation that was built from source rather
>>> than from the PPA, it successfully links and runs. What could explain this
>>> behavior?
>>>
>>>
>> Is this on the same machine?
>>
>
> Yes. You can try it for yourself if you want:
> https://github.com/superjoe30/libgroove/archive/2.0.2.tar.gz
>
>
>>
>>
>>>
>>>> Running nm -g on your static library shows that it includes undefined
>>>> static symbols for the functions that you list. If you link against those
>>>> libraries (libav and libsdl) when building test.c, this ought to work.
>>>>
>>>>
>>>>
>>>> On Tue, Nov 19, 2013 at 11:21 AM, Andrew Kelley <superjoe30@xxxxxxxxx>wrote:
>>>>
>>>>> Hello -
>>>>>
>>>>> I just added a library to my ppa:
>>>>> https://launchpad.net/~andrewrk/+archive/libgroove
>>>>> so far so good, it installs on my system. But when I compile a program
>>>>> against it, I get linker errors - undefined symbols from libraries that my
>>>>> library depends on. This does not happen when I manually build from source.
>>>>>
>>>>> Any suggestions?
>>>>>
>>>>> Here are some more details.
>>>>>
>>>>> The problem:
>>>>>
>>>>> andy@andy-bx:~/tmp$ c99 -o test test.c -lgroove
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `cleanup_save':
>>>>>
>>>>> (.text+0x29): undefined reference to `av_free_packet'
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `cleanup_save':
>>>>>
>>>>> (.text+0x39): undefined reference to `avio_closep'
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `cleanup_save':
>>>>>
>>>>> (.text+0x54): undefined reference to `avformat_free_context'
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `cleanup_save':
>>>>>
>>>>> (.text+0xa1): undefined reference to `av_log'
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `groove_file_close':
>>>>>
>>>>> (.text+0xe6): undefined reference to `av_free_packet'
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `groove_file_close':
>>>>>
>>>>> (.text+0x105): undefined reference to `avcodec_close'
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `groove_file_close':
>>>>>
>>>>> (.text+0x12b): undefined reference to `avformat_close_input'
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `groove_file_close':
>>>>>
>>>>> (.text+0x139): undefined reference to `SDL_DestroyMutex'
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `groove_file_open':
>>>>>
>>>>> (.text+0x16f): undefined reference to `av_mallocz'
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `groove_file_open':
>>>>>
>>>>> (.text+0x18f): undefined reference to `SDL_CreateMutex'
>>>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libgroove.a(file.c.o): In function `groove_file_open':
>>>>>
>>>>> (.text+0x1a1): undefined reference to `avformat_alloc_context'
>>>>> ...(snip)...
>>>>>
>>>>>
>>>>> libav is a static dependency of libgroove, and SDL2 is a dynamic dependency.
>>>>> test.c uses only libgroove, it does not depend on libav or SDL2.
>>>>>
>>>>>
>>>>> andy@andy-bx:~$ ldd /usr/lib/libgroove.so.2.0.2
>>>>> 	linux-vdso.so.1 =>  (0x00007fff499c9000)
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> 	libbz2.so.1.0 => /lib/x86_64-linux-gnu/libbz2.so.1.0 (0x00007fc04ecde000)
>>>>>
>>>>> 	libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007fc04eac5000)
>>>>> 	libmp3lame.so.0 => /usr/lib/x86_64-linux-gnu/libmp3lame.so.0 (0x00007fc04e837000)
>>>>>
>>>>> 	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fc04e61a000)
>>>>> 	libSDL2-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libSDL2-2.0.so.0 (0x00007fc04e346000)
>>>>>
>>>>> 	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fc04df7d000)
>>>>> 	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fc04dc79000)
>>>>>
>>>>>
>>>>> 	/lib64/ld-linux-x86-64.so.2 (0x00007fc04ff2a000)
>>>>> 	libasound.so.2 => /usr/lib/x86_64-linux-gnu/libasound.so.2 (0x00007fc04d989000)
>>>>> 	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fc04d784000)
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> 	libpulse-simple.so.0 => /usr/lib/x86_64-linux-gnu/libpulse-simple.so.0 (0x00007fc04d580000)
>>>>> 	libpulse.so.0 => /usr/lib/x86_64-linux-gnu/libpulse.so.0 (0x00007fc04d337000)
>>>>>
>>>>> 	libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007fc04d001000)
>>>>> 	libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007fc04cdef000)
>>>>>
>>>>> 	libXcursor.so.1 => /usr/lib/x86_64-linux-gnu/libXcursor.so.1 (0x00007fc04cbe5000)
>>>>> 	libXinerama.so.1 => /usr/lib/x86_64-linux-gnu/libXinerama.so.1 (0x00007fc04c9e1000)
>>>>>
>>>>> 	libXi.so.6 => /usr/lib/x86_64-linux-gnu/libXi.so.6 (0x00007fc04c7d1000)
>>>>> 	libXrandr.so.2 => /usr/lib/x86_64-linux-gnu/libXrandr.so.2 (0x00007fc04c5c7000)
>>>>>
>>>>> 	libXss.so.1 => /usr/lib/x86_64-linux-gnu/libXss.so.1 (0x00007fc04c3c2000)
>>>>> 	libXxf86vm.so.1 => /usr/lib/x86_64-linux-gnu/libXxf86vm.so.1 (0x00007fc04c1bc000)
>>>>>
>>>>> 	librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007fc04bfb4000)
>>>>> 	libpulsecommon-4.0.so => /usr/lib/x86_64-linux-gnu/pulseaudio/libpulsecommon-4.0.so (0x00007fc04bd4c000)
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> 	libjson-c.so.2 => /lib/x86_64-linux-gnu/libjson-c.so.2 (0x00007fc04bb42000)
>>>>> 	libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007fc04b8fc000)
>>>>>
>>>>> 	libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007fc04b6de000)
>>>>> 	libXrender.so.1 => /usr/lib/x86_64-linux-gnu/libXrender.so.1 (0x00007fc04b4d4000)
>>>>>
>>>>> 	libXfixes.so.3 => /usr/lib/x86_64-linux-gnu/libXfixes.so.3 (0x00007fc04b2cd000)
>>>>> 	libwrap.so.0 => /lib/x86_64-linux-gnu/libwrap.so.0 (0x00007fc04b0c3000)
>>>>>
>>>>> 	libsndfile.so.1 => /usr/lib/x86_64-linux-gnu/libsndfile.so.1 (0x00007fc04ae5a000)
>>>>> 	libasyncns.so.0 => /usr/lib/x86_64-linux-gnu/libasyncns.so.0 (0x00007fc04ac54000)
>>>>>
>>>>> 	libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007fc04aa50000)
>>>>> 	libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007fc04a849000)
>>>>>
>>>>> 	libnsl.so.1 => /lib/x86_64-linux-gnu/libnsl.so.1 (0x00007fc04a62f000)
>>>>> 	libFLAC.so.8 => /usr/lib/x86_64-linux-gnu/libFLAC.so.8 (0x00007fc04a3fe000)
>>>>>
>>>>> 	libvorbisenc.so.2 => /usr/lib/x86_64-linux-gnu/libvorbisenc.so.2 (0x00007fc049f2e000)
>>>>> 	libvorbis.so.0 => /usr/lib/x86_64-linux-gnu/libvorbis.so.0 (0x00007fc049d01000)
>>>>>
>>>>> 	libogg.so.0 => /usr/lib/x86_64-linux-gnu/libogg.so.0 (0x00007fc049af8000)
>>>>> 	libresolv.so.2 => /lib/x86_64-linux-gnu/libresolv.so.2 (0x00007fc0498dd000)
>>>>>
>>>>>
>>>>> # libav is not on this list because libgroove depends statically upon it
>>>>>
>>>>>
>>>>>
>>>>> here's the difference in linker steps for libgroove.so between the working manual build and the not-working PPA build:
>>>>>
>>>>> # ppa link step (broken):
>>>>>
>>>>> /usr/bin/cc  -fPIC -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2  -O2 -g -DNDEBUG -Wl,-Bsymbolic  -Wl,-z,relro -shared -Wl,-soname,libgroove.so.2 -o libgroove.so.2.0.2 CMakeFiles/groove.dir/src/queue.c.o CMakeFiles/groove.dir/src/loudness_detector.c.o CMakeFiles/groove.dir/src/buffer.c.o CMakeFiles/groove.dir/src/encoder.c.o CMakeFiles/groove.dir/src/file.c.o CMakeFiles/groove.dir/src/playlist.c.o CMakeFiles/groove.dir/src/global.c.o CMakeFiles/groove.dir/src/player.c.o deps/libav/install/lib/libavfilter.a deps/libav/install/lib/libavformat.a deps/libav/install/lib/libavcodec.a deps/libav/install/lib/libavresample.a deps/libav/install/lib/libswscale.a deps/libav/install/lib/libavutil.a -lbz2 -lz -lmp3lame -lpthread -Wl,-Bstatic -lSDL2main -Wl,-Bdynamic -lSDL2 -lpthread -Wl,-Bstatic -lebur128 -lSDL2main -Wl,-Bdynamic -lSDL2 -Wl,-Bstatic -lebur128 -Wl,-Bdynamic
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> # see full build log: https://launchpadlibrarian.net/156927161/buildlog_ubuntu-saucy-amd64.libgroove_2.0.2-2_UPLOADING.txt.gz
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> # build manually from source link step (works):
>>>>>
>>>>>
>>>>> /usr/bin/cc  -fPIC  -Wl,-Bsymbolic   -shared -Wl,-soname,libgroove.so.2 -o libgroove.so.2.0.0 CMakeFiles/groove.dir/src/global.c.o CMakeFiles/groove.dir/src/loudness_detector.c.o CMakeFiles/groove.dir/src/playlist.c.o CMakeFiles/groove.dir/src/buffer.c.o CMakeFiles/groove.dir/src/encoder.c.o CMakeFiles/groove.dir/src/queue.c.o CMakeFiles/groove.dir/src/file.c.o CMakeFiles/groove.dir/src/player.c.o deps/libav/install/lib/libavfilter.a deps/libav/install/lib/libavformat.a deps/libav/install/lib/libavcodec.a deps/libav/install/lib/libavresample.a deps/libav/install/lib/libswscale.a deps/libav/install/lib/libavutil.a -lbz2 -lz -lmp3lame -lpthread -Wl,-Bstatic -lSDL2main -Wl,-Bdynamic -lSDL2 -lpthread deps/ebur128/libebur128.a -Wl,-Bstatic -lSDL2main -Wl,-Bdynamic -lSDL2
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Mailing list: https://launchpad.net/~launchpad-users
>>>>> Post to     : launchpad-users@xxxxxxxxxxxxxxxxxxx
>>>>> Unsubscribe : https://launchpad.net/~launchpad-users
>>>>> More help   : https://help.launchpad.net/ListHelp
>>>>>
>>>>>
>>>>
>>>
>>
>