src/stdio/perror.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <errno.h>
   4 #include "stdio_impl.h"
   5
   6 void 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 }