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 = Thread::Mutex.new resource = Thread::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 } }
Class Methods
::
thread_sync.c
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static VALUE
rb_condvar_initialize(VALUE self)
{
struct rb_condvar *cv = condvar_ptr(self);
list_head_init(&cv->waitq);
return self;
}
Creates a new condition variable instance.
Instance Methods
thread_sync.c
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static VALUE
rb_condvar_broadcast(VALUE self)
{
struct rb_condvar *cv = condvar_ptr(self);
wakeup_all(&cv->waitq);
return self;
}
Wakes up all threads waiting for this lock.
#
thread_sync.c
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static VALUE
rb_condvar_signal(VALUE self)
{
struct rb_condvar *cv = condvar_ptr(self);
wakeup_one(&cv->waitq);
return self;
}
Wakes up the first thread in line waiting for this lock.
thread_sync.c
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static VALUE
rb_condvar_wait(int argc, VALUE *argv, VALUE self)
{
rb_execution_context_t *ec = GET_EC();
struct rb_condvar *cv = condvar_ptr(self);
struct sleep_call args;
rb_scan_args(argc, argv, "11", &args.mutex, &args.timeout);
struct sync_waiter sync_waiter = {
.self = args.mutex,
.th = ec->thread_ptr,
.fiber = ec->fiber_ptr
};
list_add_tail(&cv->waitq, &sync_waiter.node);
return rb_ensure(do_sleep, (VALUE)&args, delete_from_waitq, (VALUE)&sync_waiter);
}
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.
Returns the slept result on mutex
.