stdcall and cdecl stack alignment size

I have two questions:

1. Is the stack alignment for the stdcall calling convention always 4 bytes, or is it 4 for a 32 bit mach开发者_如何学编程ine and 8 for a 64 bit machine?
2. What is the stack alignment size for cdecl?

I am using Microsoft Visual Studio 2010.

Stack alignment for stdcall is always 4 bytes.

The stack alignment for cdecl is usually the size of the argument, but may be affected by compiler settings.