class Thread::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 = 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 } }
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); ccan_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.
Returns the slept result on mutex
.
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 = nonblocking_fiber(ec->fiber_ptr) }; ccan_list_add_tail(&cv->waitq, &sync_waiter.node); return rb_ensure(do_sleep, (VALUE)&args, delete_from_waitq, (VALUE)&sync_waiter); }