Qt5.1/Qt5.2 + Mac OS 10.9 (Mavericks) + XCode 5.0.2, Undefined symbols for architecture x86_64

问题

Environment : Mac OS 10.9 + Qt5.1/Qt5.2 + OpenCV2.4.7 + XCode(5.0.2)

I can compile the following program via terminal

g++ -L/usr/local/lib -lopencv_core -lopencv_highgui \
    -I/usr/local/include  main.cpp

The program a.out runs normally.

However, when using Qt 5.1/5.2 to run this OpenCV program, I got "Undefined symbols for architecture x86_64".

However, Qt5 works normally for a simple HelloWorld c++ program.

What is going on ?

Here is the code.

#include <iostream>
#include "opencv2/highgui/highgui.hpp"

using namespace std ;
using namespace cv ;

int main()
{
    Mat img ;

    img = imread("image.jpg") ;

    return 0;
}

And this is the project setting

INCLUDEPATH += /usr/local/include

LIBS += -L/usr/local/lib

LIBS += -lopencv_core -lopencv_highgui -v

cache()

TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt

SOURCES += main.cpp

Here is the compile message

/Users/XXX/Qt5.2.0/5.2.0-beta1/clang_64/bin/qmake -spec macx-clang CONFIG+=debug -o Makefile /Users/XXX/Desktop/untitled/untitled.pro

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -headerpad_max_install_names -Wl,-syslibroot

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk -mmacosx-version-min=10.6 -o untitled main.o   -L/usr/local/lib -lopencv_core -lopencv_highgui -v

with -v to show invocation

Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)
Target: x86_64-apple-darwin13.0.0
Thread model: posix

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld" -demangle -dynamic -arch x86_64 -headerpad_max_install_names -macosx_version_min 10.6.0 -o untitled -lcrt1.10.6.o -L/usr/local/lib -syslibroot

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk main.o -lopencv_core -lopencv_highgui -lstdc++ -lSystem

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/5.0/lib/darwin/libclang_rt.osx.a

And here is the error message

Undefined symbols for architecture x86_64:
"cv::imread(std::string const&, int)", referenced from:
      _main in main.o
.... and so on

I checked the problem has nothing to do with -lstdc++ or -std=c++11 or -stdlib=libstdc++. by using command line compile.

Any ideas or suggestion?

回答1:

This issue is answered in this post

http://qt-project.org/forums/viewthread/35646/

and explained by sandy.martel

I quoted here

Qt binary distribution compile with -stdlib=libstdc++ to be compatible with 10.6, Xcode 5 on 10.9 will select -stdlib=libc++ by default (for OS X 10.7 and better only). So symbol using classes from the standard library (like std::string in this case) will not resolve correctly at link time. This is why you’re seeing this error (Undefined symbols for architecture x86_64) . Look with which standard library opencv is built: otool -L libopencv_XXX.dylib. You’ll have to rebuild it with the right one or change Qt’s mkspec to use the newer one.

I solve this by changing ../Qt5.2.0/5.2.0-rc1/clang_64/mkspecs/macx-clang/qmake.conf

from

QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.6

QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.9

And remember clean your project before rebuild.

回答2:

In case you came here, because you changed config+=11 and nothing happend, try to clean your project before rebuild.

回答3:

The problem is not with the system. On Mac you just have to include imgcodecs header and include the respective lib files also. This will solve all the trouble you had.

-lopencv_imgcodecs

来源：https://stackoverflow.com/questions/20342896/qt5-1-qt5-2-mac-os-10-9-mavericks-xcode-5-0-2-undefined-symbols-for-archi

标签

macos

OpenCV

undefined

x86-64