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MWAPI - Data Exchange Events

Draft MDC Standard

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9.1.9 Data Exchange Events

Data Exchange events are associated with Data Exchange links. Unlike other MWAPI events these events are not disabled when the event owner (window or gadget) or any ancestor has its ACTIVE attribute set FALSE. Nor are the events deferred by a nested ESTART.

LINKOPEN occurs for an application window after another application establishes a link with that window. During callback processing for this event, the M[UMPS] process can remove the OK einfoattribute from ^$EVENT. In this case, the link is terminated when the callback completes.

LINKCLOSE occurs for an application window of a server when the link is terminated by the client. It occurs for the gadget of a client when the link is terminated by the server.

LINKACTION is caused when a request to perform an action on the link either completes or is not honoured within the interval defined by the gadget's LINKTIMEOUT attribute.

LINKNOTIFY is caused when a gadget's LINKMODE has the value NOTIFY, and the item defined by the gadget's LINKSOURCE and LINKITEM changes.

LINKUPDATE is caused when a gadget's LINKMODE has the value AUTOMATIC, and the item defined by the gadget's LINKSOURCE and LINKITEM changes. The event is caused after the gadget's VALUE elattribute is changed.

LINKPOKE is caused for a gadget when a client application is about to update the data source item which this gadget represents. During callback processing for this event, the M[UMPS] process can remove the OK einfoattribute from ^$EVENT, in which case the update is denied. Otherwise the new value will be assigned to the gadget immediately after the callback completes and before any other callback is processed.

LINKREQUEST is caused for a gadget when a client application requests the data source item which this gadget represents. During callback processing for this event, the M[UMPS] process can remove the OK einfoattribute from ^$EVENT, in which case the request is denied.

LINKEXECUTE is caused when a window acting as a data source is asked to execute a command. During callback processing for this event, the M[UMPS] process can remove the OK einfoattribute from ^$EVENT. In this case, the application requesting execution of the command is informed that the request failed.

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Copyright © Standard Documents; 1977-2018 MUMPS Development Committee;
Copyright © Examples: 1995-2018 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2018 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 21-Mar-2004, 19:02:24 .

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