class ConditionVariable
ConditionVariable objects augment class Mutex. Using condition variables, it is possible to suspend while in the middle of a critical section until a resource becomes available.
Example:
mutex = Mutex.new resource = ConditionVariable.new a = Thread.new { mutex.synchronize { # Thread 'a' now needs the resource resource.wait(mutex) # 'a' can now have the resource } } b = Thread.new { mutex.synchronize { # Thread 'b' has finished using the resource resource.signal } }
Public Class Methods
new()
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Creates a new condition variable instance.
static VALUE
rb_condvar_initialize(VALUE self)
{
struct rb_condvar *cv = condvar_ptr(self);;
list_head_init(&cv->waitq);
return self;
}
Public Instance Methods
broadcast()
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Wakes up all threads waiting for this lock.
static VALUE
rb_condvar_broadcast(VALUE self)
{
struct rb_condvar *cv = condvar_ptr(self);
wakeup_all(&cv->waitq);
return self;
}
signal()
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Wakes up the first thread in line waiting for this lock.
static VALUE
rb_condvar_signal(VALUE self)
{
struct rb_condvar *cv = condvar_ptr(self);
wakeup_one(&cv->waitq);
return self;
}
wait(mutex, timeout=nil)
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Releases the lock held in mutex and waits; reacquires the lock
on wakeup.
If timeout is given, this method returns after
timeout seconds passed, even if no other thread doesn't
signal.
static VALUE
rb_condvar_wait(int argc, VALUE *argv, VALUE self)
{
struct rb_condvar *cv = condvar_ptr(self);
VALUE mutex, timeout;
struct sleep_call args;
struct sync_waiter w;
rb_scan_args(argc, argv, "11", &mutex, &timeout);
args.mutex = mutex;
args.timeout = timeout;
w.th = GET_THREAD();
list_add_tail(&cv->waitq, &w.node);
rb_ensure(do_sleep, (VALUE)&args, delete_from_waitq, (VALUE)&w);
return self;
}