T-Kernel Specification (1.B0.02)

4.6. MEMORY POOL MANAGEMENT FUNCTIONS 151
tk get mpf
Get Fixed-size Memory Block
[C Language Interface]
ER ercd = tk_get_mpf ( ID mpfid, VP *p_blf, TMO tmout ) ;
[Parameters]
ID mpfid Fixed-size memory pool ID
TMO tmout Timeout designation
[Return Parameters]
ER ercd Error code
VP blf Memory block start address
[Error Codes]
E OK
E ID
E NOEXS
E PAR
E DLT
E RLWAI
E DISWAI
E TMOUT
E CTX
Normal completion
Invalid ID number (mpfid is invalid or cannot be used)
Object does not exist (the fixed-size memory pool designated in mpfid does not exist)
Parameter error (tmout ≤ (−2))
The object being waited for was deleted (the memory pool was deleted while waiting)
Wait state released (tk rel wai received in wait state)
Wait released by wait disabled state
Polling failed or timeout
Context error (issued from task-independent portion or in dispatch disabled state)
[Description]
Gets a memory block from the fixed-size memory pool designated in mpfid. The start address of
the allocated memory block is returned in blf. The size of the allocated memory block is the value
designated in the blfsz parameter when the fixed-size memory pool was created.
The allocated memory is not cleared to zero, and the memory block contents are indeterminate.
If a block cannot be allocated from the designated memory pool, the task that issued tk get blf is put
in the queue of tasks waiting for memory allocation from that memory pool, and waits until memory
can be allocated.
A maximum wait time (timeout) can be set in tmout. If the tmout time elapses before the wait release
condition is met (memory space does not become available), the system call terminates, returning
timeout error code E TMOUT.
Only positive values can be set in tmout. The time base for tmout (time unit) is the same as that for
system time (= 1 ms).
When TMO POL = 0 is set in tmout, this means 0 was designated as the timeout value, and E TMOUT is
returned without entering WAIT state even if memory cannot be allocated.
Copyright c○ 2002, 2003 by T-Engine Forum
T-Kernel 1.B0.02