src/stdio/getc.h

   1 #include "stdio_impl.h"
   2 #include "pthread_impl.h"
   3
   4 #ifdef __GNUC__
   5 __attribute__((__noinline__))
   6 #endif
   7 static int locking_getc(FILE *f)
   8 {
   9         if (a_cas(&f->lock, 0, MAYBE_WAITERS-1)) __lockfile(f);
  10         int c = getc_unlocked(f);
  11         if (a_swap(&f->lock, 0) & MAYBE_WAITERS)
  12                 __wake(&f->lock, 1, 1);
  13         return c;
  14 }
  15
  16 static inline int do_getc(FILE *f)
  17 {
  18         int l = f->lock;
  19         if (l < 0 || l && (l & ~MAYBE_WAITERS) == __pthread_self()->tid)
  20                 return getc_unlocked(f);
  21         return locking_getc(f);
  22 }