trcv_mbx

Outline

Receive from mailbox (with timeout).

C format

 ER      trcv_mbx (ID mbxid, T_MSG **ppk_msg, TMO tmout);

Parameter(s)

I/O	Parameter	Description
I	ID mbxid;	ID number of the mailbox from which a message is received.
O	T_MSG **ppk_msg;	Start address of the message packet received from the mailbox.
I	TMO tmout;	Specified timeout (unit:millisecond). TMO_FEVR: Waiting forever. TMO_POL: Polling. Value: Specified timeout.

[Message packet: T_MSG]

typedef struct t_msg { struct t_msg *msgnext; /*Reserved for future use*/ } T_MSG;

[Message packet: T_MSG_PRI]

typedef struct t_msg_pri { struct t_msg msgque; /*Reserved for future use*/ PRI msgpri; /*Message priority*/ } T_MSG_PRI;

Explanation

This service call receives a message from the mailbox specified by parameter mbxid, and stores its start address in the area specified by parameter ppk_msg.

If no message could be received from the target mailbox (no messages were queued to the wait queue) when this service call is issued, this service call does not receive messages but queues the invoking task to the target mailbox wait queue and moves it from the RUNNING state to the WAITING state with timeout (message reception wait state).

The receiving WAITING state for a mailbox is cancelled in the following cases, and then moved to the READY state.

Receiving WAITING State for a Mailbox Cancel Operation	Return Value
A message was transmitted to the target mailbox as a result of issuing snd_mbx.	E_OK
A message was transmitted to the target mailbox as a result of issuing isnd_mbx.	E_OK
Forced release from waiting (accept rel_wai while waiting).	E_RLWAI
Forced release from waiting (accept irel_wai while waiting).	E_RLWAI
Polling failure or timeout.	E_TMOUT

Note 1 Invoking tasks are queued to the target mailbox wait queue in the order defined during configuration (FIFO order or priority order).

Note 2 If the message reception wait state is cancelled because rel_wai or irel_wai was issued or the wait time elapsed, the contents in the area specified by parameter ppk_msg become undefined.

Note 3 TMO_FEVR is specified for wait time tmout, processing equivalent to rcv_mbx will be executed. When TMO_POL is specified, processing equivalent to prcv_mbx /iprcv_mbx will be executed.

Note 4 For details about the message packet, refer to "15.2.6 Message packet".

Return value

Macro	Value	Description
E_OK	0	Normal completion.
E_PAR	-17	Parameter error. - tmout < TMO_FEVR
E_ID	-18	Invalid ID number. - mbxid < 0x0 - mbxid > Maximum ID number
E_CTX	-25	Context error. - This service call was issued from a non-task. - This service call was issued in the CPU locked state. - This service call was issued in the dispatching disabled state.
E_NOEXS	-42	Non-existent object. - Specified mailbox is not registered.
E_RLWAI	-49	Forced release from the WAITING state. - Accept rel_wai/irel_wai while waiting.
E_TMOUT	-50	Timeout. - Polling failure or timeout.