在Ubuntu 14.04上从源代码编译时如何链接到opencv 3.0？

Question

我试图编译和链接，我发现下面的OpenCV程序在线：

main.cpp中：

#include <opencv2/highgui.hpp> 
#include <opencv2/imgproc.hpp> 
#include <opencv2/videoio.hpp> 

#include <iostream> 
#include <stdio.h> 

using namespace std; 
using namespace cv; 
int main(int argc, const char** argv) 
{ 
     VideoCapture capture(0); 

     while(capture.isOpened()) 
     { 
       Mat frame; 
       if (! capture.read(frame)) 
         continue; 

       imshow("lalala", frame); 
       if(waitKey(10) == 27) 
         break; 
     } 



     return 0; 
} 

我filestructure如下：

〜的/ dev/opencv- 1

〜的/ dev/OpenCV的-示例

OpenCV的-1是一个git克隆：https://github.com/Itseez/opencv

我跟着位于中的说明：http://docs.opencv.org/trunk/doc/tutorials/introduction/linux_install/linux_install.html

我的目标是要调试到OpenCV的代码，所以我用了CMAKE_BUILD_TYPE =调试

我能得到OpenCV的代码编译sucessfuly。我写了下面的makefile编译这个样本：

INCPATH =-I../opencv-1/modules/objdetect/include \ 
    -I../opencv-1/modules/highgui/include \ 
    -I../opencv-1/modules/imgproc/include \ 
    -I../opencv-1/modules/core/include \ 
    -I../opencv-1/modules/imgcodecs/include \ 
    -I../opencv-1/modules/videoio/include \ 

LIBPATH =-L../opencv-1/debug/lib 

LIBS =-lopencv_core -lopencv_videoio -lopencv_highgui -lopencv_imgproc -lopencv_video -lopencv_objdetect 

%:%.cpp 
     g++ $(INCPATH) $(LIBS) $(LIBPATH) $^ -o $@ 

编译我跑：使主

发生这种情况时，我得到以下链接错误：

g++ -I../opencv-1/modules/objdetect/include -I../opencv-1/modules/highgui/include -I../opencv-1/module                s/imgproc/include -I../opencv-1/modules/core/include -I../opencv-1/modules/imgcodecs/include -I../open                cv-1/modules/videoio/include -lopencv_core -lopencv_videoio -lopencv_highgui -lopencv_imgproc -lopenc                v_video -lopencv_objdetect -L../opencv-1/debug/lib main.cpp -o main 
/tmp/cc0PMDdW.o: In function `main': 
main.cpp:(.text+0x29): undefined reference to `cv::VideoCapture::VideoCapture(int)' 
main.cpp:(.text+0x69): undefined reference to `cv::VideoCapture::read(cv::_OutputArray const&)' 
main.cpp:(.text+0xce): undefined reference to `cv::imshow(cv::String const&, cv::_InputArray const&)' 
main.cpp:(.text+0xf6): undefined reference to `cv::waitKey(int)' 
main.cpp:(.text+0x131): undefined reference to `cv::VideoCapture::isOpened() const' 
main.cpp:(.text+0x14d): undefined reference to `cv::VideoCapture::~VideoCapture()' 
main.cpp:(.text+0x1b0): undefined reference to `cv::VideoCapture::~VideoCapture()' 
/tmp/cc0PMDdW.o: In function `cv::String::String(char const*)': 
main.cpp:(.text._ZN2cv6StringC2EPKc[_ZN2cv6StringC5EPKc]+0x4f): undefined reference to `cv::String::al                locate(unsigned long)' 
/tmp/cc0PMDdW.o: In function `cv::String::~String()': 
main.cpp:(.text._ZN2cv6StringD2Ev[_ZN2cv6StringD5Ev]+0x14): undefined reference to `cv::String::deallo                cate()' 
/tmp/cc0PMDdW.o: In function `cv::_InputArray::_InputArray()': 
main.cpp:(.text._ZN2cv11_InputArrayC2Ev[_ZN2cv11_InputArrayC5Ev]+0x13): undefined reference to `vtable                for cv::_InputArray' 
/tmp/cc0PMDdW.o: In function `cv::_InputArray::_InputArray(cv::Mat const&)': 
main.cpp:(.text._ZN2cv11_InputArrayC2ERKNS_3MatE[_ZN2cv11_InputArrayC5ERKNS_3MatE]+0x17): undefined re                ference to `vtable for cv::_InputArray' 
/tmp/cc0PMDdW.o: In function `cv::_InputArray::~_InputArray()': 
main.cpp:(.text._ZN2cv11_InputArrayD2Ev[_ZN2cv11_InputArrayD5Ev]+0x13): undefined reference to `vtable                for cv::_InputArray' 
/tmp/cc0PMDdW.o: In function `cv::_OutputArray::_OutputArray(cv::Mat&)': 
main.cpp:(.text._ZN2cv12_OutputArrayC2ERNS_3MatE[_ZN2cv12_OutputArrayC5ERNS_3MatE]+0x23): undefined re                ference to `vtable for cv::_OutputArray' 
/tmp/cc0PMDdW.o: In function `cv::_OutputArray::~_OutputArray()': 
main.cpp:(.text._ZN2cv12_OutputArrayD2Ev[_ZN2cv12_OutputArrayD5Ev]+0x13): undefined reference to `vtab                le for cv::_OutputArray' 
/tmp/cc0PMDdW.o: In function `cv::Mat::~Mat()': 
main.cpp:(.text._ZN2cv3MatD2Ev[_ZN2cv3MatD5Ev]+0x39): undefined reference to `cv::fastFree(void*)' 
/tmp/cc0PMDdW.o: In function `cv::Mat::release()': 
main.cpp:(.text._ZN2cv3Mat7releaseEv[_ZN2cv3Mat7releaseEv]+0x4b): undefined reference to `cv::Mat::dea                llocate()' 
collect2: error: ld returned 1 exit status 
make: *** [main] Error 1 

我不是确定我错过了什么。我已经包含了这个简单程序需要编译的所有库。我在网上搜索了类似的错误，并且我看到的所有答案都建议添加已经存在于我的makefile中的库。

Answer 1

你的问题是，这条线：

g++ $(INCPATH) $(LIBS) $(LIBPATH) $^ -o $@ 

应重新写成这样：

$(CXX) $(INCPATH) $(LIBPATH) $^ $(LIBS) -o $@ 

含-l标志的变量应该总是去后的.cpp或.o文件命令行。

---

但是你可以做得更好。你的Makefile应该看起来像这样：

CPPFLAGS := -I../opencv-1/modules/objdetect/include \ 
       -I../opencv-1/modules/highgui/include \ 
       -I../opencv-1/modules/imgproc/include \ 
       -I../opencv-1/modules/core/include \ 
       -I../opencv-1/modules/imgcodecs/include \ 
       -I../opencv-1/modules/videoio/include 

LDFLAGS  := -L../opencv-1/debug/lib 

LDLIBS  := -lopencv_core -lopencv_videoio -lopencv_highgui \ 
       -lopencv_imgproc -lopencv_video -lopencv_objdetect 

没有更多，没什么。 GNU Make已经有一个隐含的规则来编译一个.cpp文件到一个可执行文件中，只需通过使用内置变量来依赖它。

注意：CPPFLAGS表示预处理器标志，而不是C++标志。使用CXXFLAGS来提供标志，例如-std或-g标志。