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
   7 int fflush(FILE *f)
   8 {
   9         if (!f) {
  10                 int r = __stdout_used ? fflush(__stdout_used) : 0;
  11
  12                 for (f=*__ofl_lock(); f; f=f->next) {
  13                         FLOCK(f);
  14                         if (f->wpos != f->wbase) r |= fflush(f);
  15                         FUNLOCK(f);
  16                 }
  17                 __ofl_unlock();
  18
  19                 return r;
  20         }
  21
  22         FLOCK(f);
  23
  24         /* If writing, flush output */
  25         if (f->wpos != f->wbase) {
  26                 f->write(f, 0, 0);
  27                 if (!f->wpos) {
  28                         FUNLOCK(f);
  29                         return EOF;
  30                 }
  31         }
  32
  33         /* If reading, sync position, per POSIX */
  34         if (f->rpos != f->rend) f->seek(f, f->rpos-f->rend, SEEK_CUR);
  35
  36         /* Clear read and write modes */
  37         f->wpos = f->wbase = f->wend = 0;
  38         f->rpos = f->rend = 0;
  39
  40         FUNLOCK(f);
  41         return 0;
  42 }
  43
  44 weak_alias(fflush, fflush_unlocked);