usr/src/lib/libc/string/strncmp.c

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not 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 defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)strncmp.c   5.4 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <sys/stdc.h>
#include <string.h>

int
strncmp(s1, s2, n)
        register const char *s1, *s2;
        register size_t n;
{

        if (n == 0)
                return (0);
        do {
                if (*s1 != *s2++)
                        return (*(unsigned char *)s1 - *(unsigned char *)--s2);
                if (*s1++ == 0)
                        break;
        } while (--n != 0);
        return (0);
}