ret, retn, retf - how to use them

Question

I have the following asm code:

; int __stdcall wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR lpCmdLine, int nShowCmd)
_wWinMain@16 proc near
         


        

Answer 1

In the mnemonic ret N, N is the size of parameters on the stack. In this case it is 4 * 4 = 16 (10h) for 4 DWORDs.
But this only applies to calling conventions when the callee is responsible for stack cleanup. In case of cdecl convention the ret should be without any numbers, as the caller is responsible for stack cleanup.