Solve boost: asio WinSock. h has already been included

Recently, the code of the new face detection algorithm always prompts WinSock. h has already been included. Someone has provided a solution and reprinted it to remember it.

When you start to use the boost: asio library, the following error occurs during compilation:

Fatal error C1189: # error: WinSock. h has already been pinned DED

Check the boost code that throws this error. It was originally defined as _ WINSOCKAPI _, but not _ WINSOCK2API _

Where do we define _ WINSOCKAPI?

Later, I checked it on the Internet. It turned out that I included the Windows. h header file, and the Windows. h header file included the old WinSock. h file.

It is easy to know the cause. After trying, there are three methods to solve this error:

1. Define the macro WIN32_LEAN_AND_MEAN before Windows. h. (WIN32_LEAN_AND_MEAN indicates that it does not contain materials that are rarely used and biased)

2. Include winsock2.h before Windows. h.

3. Include asio. hpp before Windows. h.

 

From http://blog.csdn.net/gzlyb/article/details/5870326