Linker Error when building Xcode project using external library

Question

I am attempting to build a very simple command line application, in Xcode, that will print out basic information about MXF video files. In order to do this I need to use the libmxf, libbmx, and libbmx libraries available for download here:

http://sourceforge.net/p/bmxlib/home/Home/

My C++ code is incredibly simple at this point:

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cerrno>
#include <vector>

#include <bmx/mxf_reader/MXFFileReader.h>
#include <bmx/mxf_reader/MXFGroupReader.h>
#include <bmx/mxf_reader/MXFSequenceReader.h>
#include <bmx/mxf_reader/MXFFrameMetadata.h>
#include <bmx/MXFUtils.h>
#include <bmx/Utils.h>

using namespace std;
using namespace bmx;

#define MXF_OPEN_READ(fn, pf)   mxf_disk_file_open_read(fn, pf)

int main(int argc, const char * argv[])
{
    std::vector<const char *> filenames;
    std::cout << "mxfheader: execution beginning...\n";
    for (int cmdln_index = 0; cmdln_index < argc; cmdln_index++) {
        if (!check_file_exists(argv[cmdln_index])) {
            if (argv[cmdln_index][0] == '-') {
                fprintf(stderr, "Unknown argument '%s'\n", argv[cmdln_index]);
            } else {
                fprintf(stderr, "Failed to open input filename '%s'\n", argv[cmdln_index]);
            }
            return 1;
        }
        filenames.push_back(argv[cmdln_index]);
    }

    std::cout << filenames[0] << "\n";
    return 0;
}

When I compiled the BMX library, I was sure to run configure with 64-bit support, like so:

./configure --build=x86_64-apple-darwin11.4.2 --host=x86_64-apple-darwin11.4.2 CFLAGS="-arch x86_64" CXXFLAGS="-arch x86_64" LDFLAGS="-arch x86_64" CC=clang CXX=clang++

In the XCode Project under Build Settings, I have added /usr/local/lib to my Search Paths. Under Build Phases, I have added "libbmx-0.1.3.dylib", "libMXF-1.0.4.dylib", and "libMXF++-1.0.4.dylib" to the "Link Binary With Libraries" section.

I have verified that these libraries are, indeed, 64-bit ( file libbmx-0.1.3.dylib returns libbmx-0.1.3.dylib: Mach-O 64-bit dynamically linked shared library x86_64 ).

Every time I try and build the application, I get the following linker error:

Ld /Users/ned/Library/Developer/Xcode/DerivedData/mxfheader-bkwawmplsoqpdadfxartceqkbolo/Build/Products/Debug/mxfheader normal x86_64
    cd /Users/ned/Documents/src/mxfheader
    setenv MACOSX_DEPLOYMENT_TARGET 10.7
    /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk -L/Users/ned/Library/Developer/Xcode/DerivedData/mxfheader-bkwawmplsoqpdadfxartceqkbolo/Build/Products/Debug -L/usr/local/lib -F/Users/ned/Library/Developer/Xcode/DerivedData/mxfheader-bkwawmplsoqpdadfxartceqkbolo/Build/Products/Debug -filelist /Users/ned/Library/Developer/Xcode/DerivedData/mxfheader-bkwawmplsoqpdadfxartceqkbolo/Build/Intermediates/mxfheader.build/Debug/mxfheader.build/Objects-normal/x86_64/mxfheader.LinkFileList -mmacosx-version-min=10.7 -stdlib=libc++ -lbmx-0.1.3 -lMXF-1.0.4 -lMXF++-1.0.4 -o /Users/ned/Library/Developer/Xcode/DerivedData/mxfheader-bkwawmplsoqpdadfxartceqkbolo/Build/Products/Debug/mxfheader

Undefined symbols for architecture x86_64:
  "bmx::check_file_exists(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >)", referenced from:
      _main in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Any help would be appreciated. Thanks!

score 9 · Accepted Answer · answered Oct 16 '12 at 18:03

9

Your problem is the option: -stdlib=libc++ in the command line. It's causing a link to the wrong libc++, you need to make it -stdlib=libstdc++, as this is the stdlib that the libbmx library is compiled against.

under the Apple LLVM compiler options for the C++ standard library, select: libstdc++, or pick compiler default (which should choose libstdc++ also)

answered Oct 16 '12 at 18:03

Anya Shenanigans

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Petesh, My reputation prohibits me from voting this up, but this is the exact solution. ONE MILLION TIMES THANK YOU!!! I was tearing my hair out on this one. – Ned W. Oct 17 '12 at 02:03
For the n00bs, like myself, here is a (hopefully) idiot-proof guide. Within Xcode, click on the "Show the Project Navigator" icon, a little folder in the top left. Click on the top level item, which will be your project. In the window that is displayed, select your primary target. In the build settings tab, select All settings, and select "Combined" instead of "Levels". Scroll down until you see the "Apple LLVM compiler 4.1 - Language" group. Locate the "C++ Standard Library" key, and change its value from libc++ to libstdc++. – Ned W. Oct 17 '12 at 02:09

Linker Error when building Xcode project using external library

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