1#include <stdio.h>
2#include <string.h>
3#include <errno.h>
4#include "stdio_impl.h"
5
6void perror(const char *msg)
7{
8 FILE *f = stderr;
9 char *errstr = strerror(errno);
10
11 FLOCK(f);
12
13 /* Save stderr's orientation and encoding rule, since perror is not
14 * permitted to change them. */
15 void *old_locale = f->locale;
16 int old_mode = f->mode;
17
18 if (msg && *msg) {
19 fwrite(msg, strlen(msg), 1, f);
20 fputc(':', f);
21 fputc(' ', f);
22 }
23 fwrite(errstr, strlen(errstr), 1, f);
24 fputc('\n', f);
25
26 f->mode = old_mode;
27 f->locale = old_locale;
28
29 FUNLOCK(f);
30}