Macro compilation preprocessing header Win32_ LEAN_ AND_ MEAN

   In many windows In projects under , We can often see in stdafx.h There is such a macro definition in #define WIN32_LEAN_AND_MEAN, Its function is actually when our project includes <windows.h> Remove the inclusion of some header files , Speed up compilation , You can jump into <windows.h> Search for WIN32_LEAN_AND_MEAN You can see which header files have been removed , According to the Internet, it is not used MFC Can include the preprocessing header , I also tested it with a small project , Basically, it has little impact on the compilation speed and the generated files , So I personally think that as long as everyone knows that there is such a thing , When reading other people's code, if there is such a thing that can know what it is doing .