opencv源码解读一

　　在opencv中，有CV_EXPORTS是什么意思呢？其定义在cvdef中：

#ifdef CVAPI_EXPORTS
# if (defined _WIN32 || defined WINCE || defined __CYGWIN__)
#   define CV_EXPORTS __declspec(dllexport)
# elif defined __GNUC__ && __GNUC__ >= 4
#   define CV_EXPORTS __attribute__ ((visibility ("default")))
# endif
#endif　　

参考博客：https://blog.csdn.net/weixin_30929295/article/details/95231535