PxToRequest_EvWait()

Request a timeout object while waiting for events.

APPLIES TO

1.0.0

SYNOPSIS

PxTo_t PxToRequest_EvWait (PxOpool_t OpoolId, PxTicks_t timeout, PxEvents_t events, PxEvents_t abortevents);

ARGUMENTS

OpoolId: The object pool to request the timeout object from

timeout: Number of ticks after which the event is signalled

events: Events to be signalled after period ticks

abortevents: Event mask with events making the call return

RETURN VALUES

Invalid timeout object on failure
Timeout object on success
Events, if request aborted by an event

ERROR CODES

PXERR_OPOOL_ILLOPOOL

The passed object pool handle is invalid

PXERR_OBJ_NOOBJ

No free object is available

PXERR_OBJ_ABORTED

The request was aborted by an event

PXERR_OBJ_ILLOBJ

The passed object handle is not valid

PXERR_GLOBAL_ILLEGAL_CORE

The requested object pool is not on the same core

PXERR_EVENT_ZERO

The given event mask is zero

PXERR_ACCESS_RIGHT

The calling task has not the right to access the object pool

PXERR_INTERNAL_INCONSISTENCY-

Inconsistency of internal structures

PXERR_TO_ILLTO

The given object is no timeout object

DESCRIPTION

PxToRequest_EvWait creates and initializes a timeout event handler object, which is returned. It is associated with period and events. System resources are allocated, as needed, to signal events to the calling task after a period of ticks has passed since the timeout is started (PxToStart). It is necessary to finish up with PxToRelease, when the timeout event is no longer used. If there is no object available in the object pool OpoolId, the PxToRequest_EvWait waits until a free object is available or until an event from mask of the events occurs.

IMPLEMENTATION GUIDELINES

Before call

OpoolId must be a valid PXROS-HR object pool and the calling task must have the access right to take objects from this object pool (V). The validity of OpoolId may also be checked by the PxOpoolIsValid macro (F). The object pool must be created on the same core as the caller runs on. The creator core id can be read with the macro PxOpoolCoreId and the own core id with PxGetCoreId (C). Typically the task’s default object pool PXOpoolTaskdefault is used for this purpose.
The timeout parameter must have a plausible value. It should be a constant or the result of a PxTickGetTicksFromMilliSeconds call (V);
The parameter events contains an event bit and should not be zero. Typically the event is a constant (V).
The parameter abortevents contains a bitmask of events awaited and should not be zero. Typically the event mask is a constant (V).

After call

The returned value is a structure of type PxToEvent_t. The received events are stored in the events part, the delay id is given in the to part of the structure. This id may be checked with one of the following macros:
- PxToIdIsValid() must be true.
- PxToIdGet() must not be _PXIllegalObjId.
- PxToIdError() must be PXERR_NOERROR otherwise the returned error code has to be interpreted (C).

Best Practice

PxToRequest_EvWait may block, if no PXROS-HR object is available and no instance (task or handler) sends an event. If blocking calls are prohibited, PxToRequest_NoWait() should be used instead or the call should be monitored by the PXROS-HR PxTo mechanism.
PxToRequest_EvWait should only be called during initialization to ensure the availability of the timeout object.

SEE ALSO

USAGE

#include "pxdef.h"

#define MY_EVENT 0x1l
#define TICKS 0x1l

PxTo_t To = PxToRequest_EvWait(OpoolId, TICKS, MY_EVENT, abortevents);

if (PxToIdError(To) != PXERR_NOERROR){
    // Report error
}