Calling Conventions

http://www.codeproject.com/Articles/1388/Calling-Conventions-Demystified

Because the stack is cleaned by the called function, the __stdcall calling convention creates smaller executables than __cdecl, in which the code for stack cleanup must be generated for each function call. On the other hand, functions with the variable number of arguments (like printf()) must use __cdecl, because only the caller knows the number of arguments in each function call; therefore only the caller can perform the stack cleanup.