getc.h raw

   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  }
  23