src/stdio/fflush.c

   1 #include "stdio_impl.h"
   2
   3 /* stdout.c will override this if linked */
   4 static FILE *volatile dummy = 0;
   5 weak_alias(dummy, __stdout_used);
   6 weak_alias(dummy, __stderr_used);
   7
   8 int fflush(FILE *f)
   9 {
  10         if (!f) {
  11                 int r = 0;
  12                 if (__stdout_used) r |= fflush(__stdout_used);
  13                 if (__stderr_used) r |= fflush(__stderr_used);
  14
  15                 for (f=*__ofl_lock(); f; f=f->next) {
  16                         FLOCK(f);
  17                         if (f->wpos != f->wbase) r |= fflush(f);
  18                         FUNLOCK(f);
  19                 }
  20                 __ofl_unlock();
  21
  22                 return r;
  23         }
  24
  25         FLOCK(f);
  26
  27         /* If writing, flush output */
  28         if (f->wpos != f->wbase) {
  29                 f->write(f, 0, 0);
  30                 if (!f->wpos) {
  31                         FUNLOCK(f);
  32                         return EOF;
  33                 }
  34         }
  35
  36         /* If reading, sync position, per POSIX */
  37         if (f->rpos != f->rend) f->seek(f, f->rpos-f->rend, SEEK_CUR);
  38
  39         /* Clear read and write modes */
  40         f->wpos = f->wbase = f->wend = 0;
  41         f->rpos = f->rend = 0;
  42
  43         FUNLOCK(f);
  44         return 0;
  45 }
  46
  47 weak_alias(fflush, fflush_unlocked);