src/stdio/ftell.c

   1 #include "stdio_impl.h"
   2 #include <limits.h>
   3 #include <errno.h>
   4
   5 off_t __ftello_unlocked(FILE *f)
   6 {
   7         off_t pos = f->seek(f, 0,
   8                 (f->flags & F_APP) && f->wpos != f->wbase
   9                 ? SEEK_END : SEEK_CUR);
  10         if (pos < 0) return pos;
  11
  12         /* Adjust for data in buffer. */
  13         if (f->rend)
  14                 pos += f->rpos - f->rend;
  15         else if (f->wbase)
  16                 pos += f->wpos - f->wbase;
  17         return pos;
  18 }
  19
  20 off_t __ftello(FILE *f)
  21 {
  22         off_t pos;
  23         FLOCK(f);
  24         pos = __ftello_unlocked(f);
  25         FUNLOCK(f);
  26         return pos;
  27 }
  28
  29 long ftell(FILE *f)
  30 {
  31         off_t pos = __ftello(f);
  32         if (pos > LONG_MAX) {
  33                 errno = EOVERFLOW;
  34                 return -1;
  35         }
  36         return pos;
  37 }
  38
  39 weak_alias(__ftello, ftello);