get_mpf

Outline

Acquire fixed-sized memory block (waiting forever).

C format

 ER      get_mpf (ID mpfid, VP *p_blk);

Parameter(s)

I/O	Parameter	Description
I	ID mpfid;	ID number of the fixed-sized memory pool.
O	VP *p_blk;	Start address of the acquired memory block.

Explanation

This service call acquires the fixed-sized memory block from the fixed-sized memory pool specified by parameter mpfid and stores the start address in the area specified by parameter p_blk.

If no fixed-size memory blocks could be acquired from the target fixed-size memory pool (no available fixed-size memory blocks exist) when this service call is issued, this service call does not acquire the fixed-size memory block but queues the invoking task to the target fixed-size memory pool wait queue and moves it from the RUNNING state to the WAITING state (fixed-size memory block acquisition wait state).

The WAITING state for a fixed-sized memory block is cancelled in the following cases.

WAITING State for a Fixed-sized Memory Block Cancel Operation	Return Value
A fixed-sized memory block was returned to the target fixed-sized memory pool as a result of issuing rel_mpf.	E_OK
A fixed-sized memory block was returned to the target fixed-sized memory pool as a result of issuing irel_mpf.	E_OK
Forced release from waiting (accept rel_wai while waiting).	E_RLWAI
Forced release from waiting (accept irel_wai while waiting).	E_RLWAI
The fixed-sized memory pool is reset as a result of issuing vrst_mpf.	EV_RST
Forced release from waiting (accept del_mpf while waiting).	E_DLT

Note 1 Invoking tasks are queued to the target fixed-size memory pool wait queue in the order defined at creating the fixed-sized memory pool. (FIFO order or current priority order).

Note 2 The contents of the block are undefined.

Note 3 The alignment number of memory block is 1. Please perform the following, in order to enlarge the alignment number of memory blocks.

- Specify the memory block size to a multiple of the desired alignment number at creating the fixed-sized memory pool.

- Make the start address of the fixed-sized memory pool area into the address of the desired alignment number.

Return value

Macro	Value	Description
E_OK	0	Normal completion.
E_PAR	-17	Parameter error. - p_blk == NULL
E_ID	-18	Invalid ID number. - mpfid < 0 - mpfid > VTMAX_MPF
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. - This service call was issued in the status "PSW.IPL > kernel interrupt mask level".
E_MACV	-26	Memory access violation. - Stack pointer points out of user stack for invoking task. - The operand-write access to the area indicated by p_blk has not been permitted to the invoking task.
E_NOEXS	-42	Non-existent object. - The fixed-sized memory pool specified by mpfid does not exist.
E_RLWAI	-49	Forced release from the WAITING state. - Accept rel_wai/irel_wai while waiting.
E_DLT	-51	Waiting object deleted. - Accept del_mpf while waiting.
EV_RST	-127	Released from WAITING state by the object reset (vrst_mpf)