usr/src/lib/libc/stdio/perror.c

/*
 * Copyright (c) 1988 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 MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)perror.c    5.6 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <sys/uio.h>

int errno;
extern int sys_nerr;
extern char *sys_errlist[];

perror(s)
        char *s;
{
        struct iovec iov[4];
        register struct iovec *v = iov;

        if (s && *s) {
                v->iov_base = s;
                v->iov_len = strlen(s);
                v++;
                v->iov_base = ": ";
                v->iov_len = 2;
                v++;
        }
        v->iov_base = (u_int)errno < sys_nerr ?
            sys_errlist[errno] : "Unknown error";
        v->iov_len = strlen(v->iov_base);
        v++;
        v->iov_base = "\n";
        v->iov_len = 1;
        (void)writev(2, iov, (v - iov) + 1);
}

char *
strerror(errnum)
        int errnum;
{
        return((u_int)errnum < sys_nerr ?
            sys_errlist[errnum] : "Unknown error");
}