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Trigger

Description

The Trigger property is used to further specify an RTLoad player in UniCon.

An RTLoad player corresponds to the load that a schedulable process places on a given processor. A load is the total amount of execution time that a single schedulable process requires for execution of the code it contains that applies to a particular event (see the Description section for the RTLoad player type for more information on events). An RTLoad player consists of a trigger and a set of segments. The set of segments describes the total amount of execution time required for the portion of the event that the RTLoad player is responsible for, and the trigger describes how often the set of segments is reactivated per unit of time. Together this information specifies the load that an RTLoad player places on a processor.

The Trigger property is used to specify the trigger part of the RTLoad player. An RTLoad player may only specify one Trigger. The value of the Trigger property is the name of a trigger that is defined in a TriggerDef property in the <interface> property list of the component containing the RTLoad player.

Typically, RTLoad players in client processes will contain Trigger properties, and those in server processes will not. This is because server processes are assumed to have asynchronous triggers which are not used anywhere in UniCon. Only the periodic triggers defined in client processes are used in UniCon, and they are used in the value of the Trace property (see the Description section for the TriggerDef property for more information).

Property Lists

The Trigger property can legally be specified in the property list in the following UniCon language element:

Value Syntax

The syntax of the value part of the Trigger property consists of a single <identifier> or "string" enclosed in parentheses.

Required Rule

Optional

There is no default value for the Trigger property.

Merge Rule

REPLACE

Subsequent duplicate specifications of the Trigger property in a single property list replace earlier specifications (i.e., the last specification is the one that the UniCon compiler uses).

Semantic Checks

The value of a Trigger property in an RTLoad player must name a trigger that is defined by a TriggerDef property in the <interface> property list of the component containing the RTLoad player.

Example

The following is an example of a specification of a Trigger property. It is embedded in an RTLoad player definition:

  PLAYER application1 IS RTLoad
    TRIGGER (external_interrupt1)
    SEGMENTSET (work_block1, work_block2, 
          work_block3)
  END application1
Also refer to the Example section for the TriggerDef property.


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Author: Gregory Zelesnik

Last Modified: May 12, 1996