The following lists the service calls provided by the RI78V4 as the synchronization and communication functions (mailboxes).

Table 12-13 Synchronization and Communication Functions (Mailboxes)

Service Call	Function	Origin of Service Call
snd_mbx	Send to mailbox.	Task, Non-task
rcv_mbx	Receive from mailbox (waiting forever).	Task
prcv_mbx	Receive from mailbox (polling).	Task, Non-task
trcv_mbx	Receive from mailbox (with timeout).	Task
ref_mbx	Reference mailbox state.	Task, Non-task