What does APIENTRY do?

Question

I encountered it first time and found no dedicated page on msdn. What does APIENTRY mean?

Answer 1

It's just a #define for WINAPI, which is the standard decoration for a Windows entrypoint.

#define APIENTRY    WINAPI

Answer 2

APIENTRY is an alias for WINAPI.

WINAPI itself is a definition for the type of calling convention used for windows API calls, the stdcall.

Basically this is explaining to the compiler how to handle the stack and arguments when calling this function. You don't usually need to worry about it unless you are making function pointers to these types of functions.