varargs.h

这是DOS系统的源代码,汇编写的,值得看看,对开发操作系统的人员有价值

/***
*varargs.h - XENIX style macros for variable argument functions
*
*   Copyright (c) 1985-1988, Microsoft Corporation.  All rights reserved.
*
*Purpose:
*   This file defines XENIX style macros for accessing arguments of a
*   function which takes a variable number of arguments.
*   [System V]
*
*******************************************************************************/

#ifndef _VA_LIST_DEFINED
typedef char *va_list;
#define _VA_LIST_DEFINED
#endif

#define va_dcl va_list va_alist;
#define va_start(ap) ap = (va_list)&va_alist
#define va_arg(ap,t) ((t *)(ap += sizeof(t)))[-1]
#define va_end(ap) ap = NULL