Mac下用g++编译opencv程序报错

问题描述：

在Mac下安装好opencv， 安装：
 
  bash  brew install opencv  
 
 写了一个opencv程序：
 
 ``` C++
//作用就是：取视频的每一帧，然后每隔50帧保存一次。

include

include "opencv2/opencv.hpp"

using namespace cv;
int main(int argc, char argv[])
{
CvCapture capture = cvCaptureFromAVI("./test.mp4");
int i = 0;
IplImage* img = 0;
char image_name[25];
cvNamedWindow( "vivi");
int nFrame = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_COUNT);

while (1) {
	img = cvQueryFrame(capture);
	cvShowImage("vivi", img);
	char key = cvWaitKey(20);
	
	std::cout << i << std::endl;

	i++;
	if (i % 50 != 0) 
		continue;

	sprintf(image_name, "%s%d%s", "image_", i, "_.jpg");

	cvSaveImage(image_name, img);

	if ( i == nFrame ) {
		break;
	}
}

return 0;

```

编辑好后保存为Test.cpp

编译： g++ Test.cpp -o Test

错误：

ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

大概知道是链接错误，google以后发现，是因为找到不到相应的opencv所需要的库。

解决办法:

利用pkg-config 获取相应的库， 安装命令：

brew install pkg-config

重新安装opencv

brew reinstall opencv

编译程序

g++ $(pkg-config --cflags --libs opencv) Test.cpp -o Test 

可以查看具体引用库

pkg-config --cflags --libs opencv

-I/usr/local/include/opencv -I/usr/local/include -L/usr/local/lib -lopencv_shape -lopencv_stitching -lopencv_objdetect -lopencv_superres -lopencv_videostab -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_video -lopencv_photo -lopencv_ml -lopencv_imgproc -lopencv_flann -lopencv_core -lopencv_hal

参考链接：

http://stackoverflow.com/questions/24985713/opencv-undefined-symbols-for-architecture-x86-64-error