Question

Contrast the three common calling conventions - cdecl, stdcall, and fastcall.

Answer 1

cdecl

__cdecl is the default calling convention for C and C++ programs. Because the stack is cleaned up by the caller, it can do vararg functions. The __cdecl calling convention creates larger executables than __stdcall, because it requires each function call to include stack cleanup code. The following list shows the implementation of this calling convention.

__stdcall

The __stdcall calling convention is used to call Win32 API functions. The callee cleans the stack, so the compiler makes vararg functions __cdecl. Functions that use this calling convention require a function prototype.

__fastcall

The __fastcall calling convention specifies that arguments to functions are to be passed in registers, when possible. This calling convention only applies to the x86 architecture. The following list shows the implementation of this calling convention.