memcmp.c

来自「c库的部分源代码 用惯了操作系统提供的内存api,你是否了解系统的运行机制,这是」· C语言 代码 · 共 24 行

/***********************************************************************\
*	Copyright 1990 Software Development Systems, Inc.		*
*	all rights reserved						*
\***********************************************************************/
#include <string.h>

int	memcmp ( s1, s2, n )
  const void	*s1;
  const void	*s2;
  size_t	 n;
{ register unsigned char *p1 = (unsigned char*) s1;
  register unsigned char *p2 = (unsigned char*) s2;
  register unsigned char *end = p1 + n;

    while ( p1 < end )
    {   if ( *p1++ != *p2++ )
	{   if ( *--p1 < *--p2 )      return ( -1 );
				else  return (  1 );
	}
    }

    return ( 0 );		/* memory blocks are equal */
}