snd_dtq

Outline

Send to data queue (waiting forever).

C format

 ER      snd_dtq (ID dtqid, VP_INT data);

Parameter(s)

I/O	Parameter	Description
I	ID dtqid;	ID number of the data queue to which the data element is sent.
I	VP_INT data;	Data element to be sent to the data queue.

Explanation

This service call writes data specified by parameter data to the data queue area of the data queue specified by parameter dtqid.

If there is no available space for writing data in the data queue area of the target data queue when this service call is issued, this service call does not write data but queues the invoking task to the transmission wait queue of the target data queue and moves it from the RUNNING state to the WAITING state (data transmission wait state).

The sending WAITING state for a data queue is cancelled in the following cases, and then moved to the READY state.

Sending WAITING State for a Data Queue Cancel Operation	Return Value
Available space was secured in the data queue area of the target data queue as a result of issuing rcv_dtq.	E_OK
Available space was secured in the data queue area of the target data queue as a result of issuing prcv_dtq.	E_OK
Available space was secured in the data queue area of the target data queue as a result of issuing iprcv_dtq.	E_OK
Available space was secured in the data queue area of the target data queue as a result of issuing trcv_dtq.	E_OK
Forced release from waiting (accept rel_wai while waiting).	E_RLWAI
Forced release from waiting (accept irel_wai while waiting).	E_RLWAI

If a task has been queued to the reception wait queue of the target data queue when this service call is issued, this service call does not write data but transfers the data to the task. As a result, the task is unlinked from the reception wait queue and moves from the WAITING state (data reception wait state) to the READY state, or from the WAITING-SUSPENDED state to the SUSPENDED state.

Note 1 Data is written to the data queue area of the target data queue in the order of the data transmission request.

Note 2 Invoking tasks are queued to the transmission wait queue of the target data queue in the order defined during configuration (FIFO order or priority order).

Return value

Macro	Value	Description
E_OK	0	Normal completion.
E_ID	-18	Invalid ID number. - dtqid < 0x0 - dtqid > 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 data queue is not registered.
E_RLWAI	-49	Forced release from the WAITING state. - Accept rel_wai/irel_wai while waiting.