strchr.c

早期freebsd实现

/*  $Revision: 1.2 $
**
**  This file has been modified to get it to compile more easily
**  on pre-4.4BSD systems.  Rich $alz, June 1991.
*/
#define NULL 0
#define STRCHR

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted provided
 * that: (1) source distributions retain this entire copyright notice and
 * comment, and (2) distributions including binaries display the following
 * acknowledgement:  ``This product includes software developed by the
 * University of California, Berkeley and its contributors'' in the
 * documentation or other materials provided with the distribution and in
 * all advertising materials mentioning features or use of this software.
 * Neither the name of the University nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#if 0
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)index.c	5.6 (Berkeley) 6/23/90";
#endif /* LIBC_SCCS and not lint */

#include <string.h>
#include <stddef.h>
#endif

char *
#ifdef STRCHR
strchr(p, ch)
#else
index(p, ch)
#endif
	register char *p, ch;
{
	for (;; ++p) {
		if (*p == ch)
			return(p);
		if (!*p)
			return((char *)NULL);
	}
	/* NOTREACHED */
}