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}