RTEMS 4.7.0 On-Line Library

Memory Pool Manager pget_blk - Poll and Get Variable-Size Memory Block

RTEMS ITRON 3.0 API User's Guide

9.4.4: pget_blk - Poll and Get Variable-Size Memory Block

CALLING SEQUENCE:

ER ercd =pget_blk(
  VP *p_blk,
  ID mplid,
  INT blksz
);

STATUS CODES:

E_OK - Normal Completion

E_ID - Invalid ID number (mplid was invalid or could not be used)

E_NOEXS - Object does not exist (the memorypool specified by mplid does not exist)

E_OACV - Object access violation (A mplid less than -4 was specified from a user task. This is implementation dependent.)

E_PAR - Parameter error (tmout is -2 or less, blksz is negative or invalid)

E_DLT - The object being waited for was deleted (the specified memorypool was deleted while waiting)

E_RLWAI - WAIT state was forcibly released (rel_wai was received while waiting)

E_TMOUT - Polling failure or timeout

E_CTX - Context error (issued from task-independent portions or a task in dispatch disabled state; implementation dependent for pget_blk and tget_blk(tmout=TMO_POL))

DESCRIPTION:

The pget_blk system call has the same function as get_blk except for the waiting feature. Pget_blk polls whether or not the task should wait if get_blk is executed. The meaning of parameters to pget_blk are the same with get_blk. The specific operations by pget_blk are as follows.

- If there is enough free memory to get the memory block of specified size immediately, processing is the same as get_blk: that is, the requested memory is allocated and the system call completes normally.

- If there is not enough free memory, an E_TMOUT error is returned to indicate polling failed and the system call finishes. Unlike get_blk, the issuing task does not wait in this case. Also, the issuing task does not get any memory.

NOTES:

NONE

RTEMS ITRON 3.0 API User's Guide