This procedure gets the first message in the message queue for the specified message port and removes the message from the queue.
Arguments
mp
The item number of the message port from which to get the message.
Return Value
The procedure returns the item number of the first message in the message queue or an error code (a negative value) if an error occurs. Possible error codes include the following:
0
The queue is empty.
BADITEM
The mp argument does not specify a message port.
NOTOWNER
The message port specified by the mp argument is not owned by this task.