Cancellable.disconnect

Disconnects a handler from a cancellable instance similar to [gobject.global.signalHandlerDisconnect]. Additionally, in the event that a signal handler is currently running, this call will block until the handler has finished. Calling this function from a #GCancellable::cancelled signal handler will therefore result in a deadlock.

This avoids a race condition where a thread cancels at the same time as the cancellable operation is finished and the signal handler is removed. See #GCancellable::cancelled for details on how to use this.

If cancellable is null or handler_id is 0 this function does nothing.