Tests whether a mailbox is empty.
mp
mailbox-empty-p mailbox => bool
| mailbox⇩ | 
A mailbox. | 
| bool | 
A boolean. | 
The function mailbox-empty-p returns t if the given mailbox is empty and nil otherwise.
mailbox-not-empty-p
mailbox-send
mailbox-peek
mailbox-read
make-mailbox
19.6.3 Communication between processes and synchronization
LispWorks® User Guide and Reference Manual - 01 Dec 2021 19:30:51