Class: Thread::ConditionVariable
Relationships & Source Files | |
Inherits: | Object |
Defined in: | thread_sync.c, thread_sync.c |
Overview
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 Method Summary
-
.new
constructor
Creates a new condition variable instance.
Instance Method Summary
-
#broadcast
Wakes up all threads waiting for this lock.
-
#signal
Wakes up the first thread in line waiting for this lock.
-
#wait(mutex, timeout = nil)
Releases the lock held in
mutex
and waits; reacquires the lock on wakeup. -
#marshal_dump
Internal use only
Alias for Queue#marshal_dump.
Constructor Details
.new
Creates a new condition variable instance.
# File 'thread_sync.c', line 1497
static VALUE rb_condvar_initialize(VALUE self) { struct rb_condvar *cv = condvar_ptr(self); ccan_list_head_init(&cv->waitq); return self; }
Instance Method Details
#broadcast
Wakes up all threads waiting for this lock.
# File 'thread_sync.c', line 1571
static VALUE rb_condvar_broadcast(VALUE self) { struct rb_condvar *cv = condvar_ptr(self); wakeup_all(&cv->waitq); return self; }
#marshal_dump
Alias for Queue#marshal_dump.
#signal
Wakes up the first thread in line waiting for this lock.
# File 'thread_sync.c', line 1557
static VALUE rb_condvar_signal(VALUE self) { struct rb_condvar *cv = condvar_ptr(self); wakeup_one(&cv->waitq); return self; }
#wait(mutex, timeout = nil)
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
.
# File 'thread_sync.c', line 1531
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); }