substr.c

操作系统SunOS 4.1.3版本的源码

/*	Copyright (c) 1984 AT&T	*/
/*	  All Rights Reserved  	*/

/*	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T	*/
/*	The copyright notice above does not evidence any   	*/
/*	actual or intended publication of such source code.	*/

#ident	"@(#)substr.c 1.1 92/07/30 SMI" /* from S5R3 acct:lib/substr.c 1.3 */
/*
	Place the `len' length substring of `as' starting at `as[origin]'
	in `aresult'.
	Return `aresult'.
 
  Note: The copying of as to aresult stops if either the
	specified number (len) characters have been copied,
	or if the end of as is found.
	A negative len generally guarantees that everything gets copied.
*/

char *substr(as, aresult, origin, len)
char *as, *aresult;
int origin;
register unsigned len;
{
	register char *s, *result;

	s = as + origin;
	result = aresult;
	++len;
	while (--len && (*result++ = *s++)) ;
	if (len == 0)
		*result = 0;
	return(aresult);
}