libgo/runtime/go-closed.c

   1 /* go-closed.c -- the builtin closed function.
   2
   3    Copyright 2009 The Go Authors. All rights reserved.
   4    Use of this source code is governed by a BSD-style
   5    license that can be found in the LICENSE file.  */
   6
   7 #include "go-assert.h"
   8 #include "channel.h"
   9
  10 /* Return whether a channel is closed.  We only return true after at
  11    least one nil value has been read from the channel.  */
  12
  13 _Bool
  14 __go_builtin_closed (struct __go_channel *channel)
  15 {
  16   int i;
  17   _Bool ret;
  18
  19   i = pthread_mutex_lock (&channel->lock);
  20   __go_assert (i == 0);
  21
  22   while (channel->selected_for_receive)
  23     {
  24       i = pthread_cond_wait (&channel->cond, &channel->lock);
  25       __go_assert (i == 0);
  26     }
  27
  28   ret = channel->saw_close;
  29
  30   i = pthread_mutex_unlock (&channel->lock);
  31   __go_assert (i == 0);
  32
  33   return ret;
  34 }