定义调用约定的意义是什么? [英] What is the point of defining a calling convention?

问题描述

例如:

  int WINAPI WinMain(HINSTANCE实例，HINSTANCE prev_instance，PSTR cmd_line，int cmd_show) 

WINAPI是一个如下所示的定义:

  #define WINAPI __stdcall 

你为什么不能做

  int __stdcall WinMain(HINSTANCE实例，HINSTANCE prev_instance，PSTR cmd_line，int cmd_show) 

实际上，我认为我的问题是我对typedef的定义感到困惑.谁可以给我解释一下这个?定义有什么作用，为什么您不能只写__stdcall呢?

解决方案

因为 WINAPI 调用约定不能保证作为 __ stdcall .使用 WINAPI 的代码即使没有使用，也仍然是正确的.

您可以如您在后面的示例中那样编写函数，并且可以正常工作-这不是一个好习惯，也不能移植到调用约定是其他东西的平台上./p>

For example:

int WINAPI WinMain ( HINSTANCE instance, HINSTANCE prev_instance, PSTR cmd_line, int cmd_show )

WINAPI is a a define that looks like this:

#define WINAPI      __stdcall

why can't you just do:

int __stdcall WinMain ( HINSTANCE instance, HINSTANCE prev_instance, PSTR cmd_line, int cmd_show )

actually I think my problem is that I'm sort of confusing defines with typedef's. Can someone explain this to me? what does the define do and why can't you just write __stdcall in its place?

解决方案

Because the WINAPI calling convention is not guaranteed to be __stdcall. Code that uses WINAPI will still be correct even when it isn't.

You can write the function as in your latter example, and it'd work fine - it's just not good practice and would not be portable to a platform where the calling convention is something else.

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