RTEMS 4.8.1 On-Line Library

Eventflags Manager pol_flg - Wait for Eventflag (Polling)

RTEMS ITRON 3.0 API User's Guide

4.4.6: pol_flg - Wait for Eventflag (Polling)

CALLING SEQUENCE:

ER pol_flg(
  UINT *p_flgptn,
  ID flgid,
  UINT waiptn,
  UINT wfmode
);

STATUS CODES:

E_OK - Normal Completion

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

E_NOEXS - Object does not exist (the eventflag specified by flgid does not exist)

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

E_PAR - Parameter error (waiptn = 0, wfmode invalid, or tmout is -2 or less)

E_OBJ - Invalid object state (multiple tasks waiting for an eventflag with the TA_WSGL attribute)

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

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

E_TMOUT - Polling failure or timeout exceeded

E_CTX - Context error (issued from task-independent portions or a task in dispatch disabled state)

EN_OBJNO - An object number which could not be accessed on the target node is specified.

EN_PAR - A value outside the range supported by the target node and/or transmission packet format was specified as a parameter (a value outside supported range was specified for waiptn and tmout)

EN_RPAR - A value outside the range supported by the requesting node and/or transmission packet format was specified as a parameter (a value exceeding the range for the requesting node was specified for flgptn)

DESCRIPTION:

The pol_flg system call has the same function as wai_flg except for the waiting feature. pol_flg polls whether or not the task should wait if wai_flg is executed. The meanings of parameters to pol_flg are the same as for wai_flg. The specific operations by pol_flg are as follows.

If the target eventflag already satisfies the conditions for releasing wait given by wfmode, processing is the same as wai_flg: the eventflag is cleared if TWF_CLR is specified and the system call completes normally.
If the target eventflag does not yet satisfy the conditions for releasing wait given by wfmode, an E_TMOUT error is returned to indicate polling failed and the system call finishes. Unlike wai_flg, the issuing task does not wait in this case. The eventflag is not cleared in this case even if TWF_CLR has been specified.

NOTES:

Multiprocessing is not supported. Thus none of the "EN_" status codes will be returned.

RTEMS ITRON 3.0 API User's Guide