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ESTART

Draft MDC Standard

8.2.10 ESTArt

ESTA[RT] postcond

[ SP ]
SP estartargument


Editor’s note:
The above definition allows for at most one estartargument.
Should it not be:
    ESTA[RT] postcond

[ SP ]
SP L estartargument


    estartargument::=

L wevclass
( L wevclass )


    wevclass::=

evclass
expr V "WAPI"


ESTArt enables synchronous event processing for the selected event classes. The additional class "WAPI" is provided to enable just the synchronous event processing specified in X11.6, the MWAPI. If any of the event classes being enabled for synchronous event processing is currently enabled for asynchronous event processing, an error occurs with ecode = "M102". It is not an error to enable an event class which is already enabled for synchronous event processing.

Synchronous event processing remains activated until the termination of execution of the ESTArt command, except that synchronous event processing is implicitly deactivated at the initiation of call back processing for each event. At the conclusion of call back processing for each event, synchronous event processing is implicitly reactivated.

The three forms of ESTArt are given the following names:

   a) L evclass Selective ESTArt
b) (L evclass) Exclusive ESTArt
b) Empty argument list: ESTArt All

In the Selective ESTArt, the named event classes are enabled for synchronous event processing as described below. In the Exclusive ESTArt, all event classes except the named event classes are enabled for synchronous event processing as described below. In the ESTArt All, all event classes are enabled for synchronous event processing as described below.

When synchronous event processing is enabled for a given event class, events of that class will cause the execution of the registered event handler, if any, for that specific event (call back processing). Event classes are enabled by ESTArt only for the process executing the ESTArt command.

Call back processing can execute an ESTArt command. In this case, the effect is to change the event classes which are enabled for subsequent synchronous event processing. ESTArt commands are not nested. It is not an error to issue multiple ESTArt commands on the same event class.

The execution of an ESTArt command which starts synchronous event processing is terminated when an ESTOp command is executed during call back processing for that ESTArt command. When execution of an ESTArt command which starts synchronous event processing is terminated, execution continues with the command following that ESTArt command.

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Copyright © Standard Documents; 1977-2024 MUMPS Development Committee;
Copyright © Examples: 1995-2024 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2024 Ed de Moel.

Some specifications are "approved for inclusion in a future standard". Note that the MUMPS Development Committee cannot guarantee that such future standards will indeed be published.

This page most recently updated on 14-Nov-2023, 21:36:27.

For comments, contact Ed de Moel (demoel@jacquardsystems.com)