ref_sem

iref_sem

Outline

Reference semaphore state.

C format

 ER      ref_sem (ID semid, T_RSEM *pk_rsem);

 ER      iref_sem (ID semid, T_RSEM *pk_rsem);

Parameter(s)

I/O	Parameter	Description
I	ID semid;	ID number of the semaphore.
O	T_RSEM *pk_rsem;	Pointer to the packet returning the semaphore state.

[Semaphore state packet: T_RSEM]

typedef struct t_rsem { ID wtskid; /*Existence of waiting task*/ UINT semcnt; /*Current resource count*/ } T_RSEM;

Explanation

Stores semaphore state packet (ID number of the task at the head of the wait queue, current resource count, etc.) of the semaphore specified by parameter semid in the area specified by parameter pk_rsem.

- wtskid
Stores whether a task is queued to the semaphore wait queue.

TSK_NONE: No applicable task

Value: ID number of the task at the head of the wait queue

- semcnt
Stores the current resource count.

Return value

Macro	Value	Description
E_OK	0	Normal completion.
E_PAR	-17	Parameter error. - pk_rsem == NULL
E_ID	-18	Invalid ID number. - semid < 0 - semid > VTMAX_SEM
E_CTX	-25	Context error. - This service call was issued in the CPU locked state. - This service call was issued in the status "PSW.IPL > kernel interrupt mask level". Note When the iref_sem is issued from task or the ref_sem is issued from non-task, the context error is not detected and normal operation of the system is not guaranteed.
E_MACV	-26	Memory access violation. (only for ref_sem) - The operand-write access to the area indicated by pk_rsem has not been permitted to the invoking task.
E_NOEXS	-42	Non-existent object. - The semaphore specified by semid does not exist.