什么是"CV_EXPORTS_W"；方法 [英] What "CV_EXPORTS_W" means

问题描述

最近，我尝试在OpenCV库中查找"calcOpticalFlowPyrLK"函数的源代码.当我搜索它的定义时，我发现了一个名为"CV_EXPORTS_W"的宏.有人知道这是什么意思吗?

Recently, I try to find out the source code of the "calcOpticalFlowPyrLK" function in OpenCV library. When I searched it's definition, I found a macro named "CV_EXPORTS_W". Anybody knows it's meaning?

推荐答案

CV_EXPORTS定义为:

CV_EXPORTS_W is defined in modules/core/include/opencv2/core/types_c.h as an alias for CV_EXPORTS, and in the same file CV_EXPORTS is defined as:

#if (defined WIN32 || defined _WIN32 || defined WINCE) && defined CVAPI_EXPORTS
# define CV_EXPORTS __declspec(dllexport)
#else
# define CV_EXPORTS
#endif

换句话说，它是在定义了CVAPI_EXPORTS的Windows平台上 __declspec(dllexport) 的别名，否则它是空的.

In other words, it's an alias for __declspec(dllexport) on a windows platform where CVAPI_EXPORTS is defined, otherwise it's empty.

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