memchr.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 22 行

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

void   *memchr ( s, c, n )
  const void	*s;
  int		 c;
  size_t	 n;
{ register unsigned char  val = (unsigned char)  c;
  register unsigned char *ptr = (unsigned char*) s;
  register unsigned char *end = ptr + n;

    while ( ptr < end )
    {	if ( *ptr++ == val )
	    return ( (void*) (ptr-1) );
    }

    return ( NULL );
}