pol_sem

ipol_sem

Outline

Acquire semaphore resource (polling).

C format

 ER      pol_sem (ID semid);

 ER      isem_sem (ID semid);

Parameter(s)

I/O	Parameter	Description
I	ID semid;	ID number of the semaphore.

Explanation

This service call acquires a resource from the semaphore specified by parameter semid (subtracts 1 from the semaphore counter).

If a resource could not be acquired from the target semaphore (semaphore counter is set to 0) when this service call is issued, the counter manipulation processing is not performed but "E_TMOUT" is returned.

Return value

Macro	Value	Description
E_OK	0	Normal completion.
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 ipol_sem is issued from task or the pol_sem is issued from non-task, the context error is not detected and normal operation of the system is not guaranteed.
E_NOEXS	-42	Non-existent object. - The semaphore specified by semid does not exist.
E_TMOUT	-50	Polling failure.