Thread: Getting a return value from a DLL in (N)ASM

I do this all the time in MASM.....

Functions have different calling conventions......There's the "C" calling convention (__cdecl in VC++) where you push the params on the stack....make the call ....then pop them all back off again..........The windows API - wsprintf() uses this, and most compilers like VC++ use this by default when calling (unless told otherwise)...


Then there's the PASCAL calling convention (often implemented __stdcall in VC++) where stack balancing is done inside the function.....therefore you dont need to pop....99% of Win32 system calls use this........

As to return value.........this is usually put in the EAX register.....that register is 32Bit so it can hold a pointer or any value equal to or less than 32Bit.......

If you passed a pointer to a function you already know this value when making the call....therefore there's no need to be reminded...