1. This function moves the selected request to a queue of requests in order to make it available to other server models. The operation is canceled if the current number of elements in the queue exceeds the given limit lim and false is returned. Otherwise, true is returned and the request can no longer be accessed by the calling model.

2. If the provided request is -1 this routine only clears the availability flag of the model ( i.e. it is no longer ready to process a request). In this case the return value indicates whether the flag was reset or not: with a false result the flag was already cleared before the function call.