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c++linker-errorscentos7g729

Linking G729 library (Library exists and symbols too)

Iam currently struggeling with linking just a simple library.

I compiled and installed successfully the G729 implementation from here Belledonne G729 like this:

cmake . -DCMAKE_INSTALL_PREFIX=/usr    
make
make install

When i check the if the symbols exist they exsist:

nm /usr/lib64/libbcg729.so | less
....
0000000000001fb8 T _init
000000000000de40 T initBcg729CNGChannel
00000000000046dd T initBcg729DecoderChannel
000000000000f5c6 T initBcg729DTXChannel
0000000000005353 T initBcg729EncoderChannel
0000000000010107 T initBcg729VADChannel
....

But when i try to compile this simple main.cpp:

#include <bcg729/decoder.h>             // for bcg729DecoderChannelContextStruct


int main()
{
    bcg729DecoderChannelContextStruct* decoderChannelContext = initBcg729DecoderChannel();

    return 0;
}

I get this as result:

c++ -v main.o -o main -lbcg729

Using built-in specs.
COLLECT_GCC=c++
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu --enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto --enable-plugin --enable-initfini-array --disable-libgcj --with-isl=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/isl-install --with-cloog=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/cloog-install --enable-gnu-indirect-function --with-tune=generic --with-arch_32=x86-64 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.8.5 20150623 (Red Hat 4.8.5-16) (GCC)
COMPILER_PATH=/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/:/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/:/usr/libexec/gcc/x86_64-redhat-linux/:/usr/lib/gcc/x86_64-redhat-linux/4.8.5/:/usr/lib/gcc/x86_64-redhat-linux/
LIBRARY_PATH=/usr/lib/gcc/x86_64-redhat-linux/4.8.5/:/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/:/lib/../lib64/:/usr/lib/../lib64/:/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-o' 'main' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
 /usr/libexec/gcc/x86_64-redhat-linux/4.8.5/collect2 --build-id --no-add-needed --eh-frame-hdr --hash-style=gnu -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o main /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crt1.o /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crti.o /usr/lib/gcc/x86_64-redhat-linux/4.8.5/crtbegin.o -L/usr/lib/gcc/x86_64-redhat-linux/4.8.5 -L/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64 -L/lib/../lib64 -L/usr/lib/../lib64 -L/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../.. main.o -lbcg729 -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/lib/gcc/x86_64-redhat-linux/4.8.5/crtend.o /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crtn.o
main.o: In function `main':
/opt/cppplayground/main.cpp:39: undefined reference to `initBcg729DecoderChannel()'
collect2: error: ld returned 1 exit status

I dont get where the issue is here, since if the library wouldnt be found, the linker would complain it does not exist. But in this case the library exists and the function i want to use does also exists.

Woulbe be nice if anyone could help ;)

Thanks in advance!

Solution

  • Found it .... Since it's a C-Library i forgot to add the 'extern "C" {}' around the includes.