Function parking_lot::unpark_requeue

pub unsafe fn unpark_requeue(key_from: usize, key_to: usize, validate: &mut FnMut() -> RequeueOp, callback: &mut FnMut(RequeueOp, usize)) -> usize

Removes all threads from the queue associated with key_from, optionally unparks the first one and requeues the rest onto the queue associated with key_to.

The validate function is called while both queues are locked and can abort the operation by returning RequeueOp::Abort. It can also choose to unpark the first thread in the source queue while moving the rest by returning RequeueOp::UnparkFirstRequeueRest. Returning RequeueOp::RequeueAll will move all threads to the destination queue.

The callback function is also called while both queues are locked. It is passed the RequeueOp returned by validate and the number of threads that were removed from the original queue.

This function returns the number of threads that were removed from the original queue.

Safety

You should only call this function with an address that you control, since you could otherwise interfere with the operation of other synchronization primitives.

The validate and callback functions are called while the queue is locked and must not panic or call into any function in parking_lot.