SdsSetWatch - Set a watch routine to watch for events on a given SDS ID.

Function

Set a watch routine to watch for events on a given SDS ID.

Description

This feature is still somewhat experimental. It provides the ablity to watch certain happenings within SDS for a given SDS ID. For example, if a given SDS ID is being free-ed incorrectly - often caused by a double free,. then you can specify the SDS ID number to watch and arrange for the specified function to be invoked when that ID is free-ed.

You specify the ID, a routine to be invoked and the client data item.

Language

Declaration

void SdsSetWatch(SdsIdType id, watchRoutine, clientData, oldId, oldWatchRoutine, oldClientData, status)

Parameters

(">" input, "!" modified, "W" workspace, "<" output)

>	id	SdsIdType	Identifier to be watched. If 0, then cancel watching. If -1, then watch all IDs. Note, it is possible to watch an `ID` which is not currently in use, in that case, you will get a `SDS_WATCH_EVENT_NEWID` event when starts being used.
>	watchRoutine	SdsWatchRoutineType	The routine to be invoked when the watch is triggered. If not specified, then a message is written to stderr.
>	clientData	void `*`	Passed through to watchRoutine as its client data item.
<	oldId	SdsIdType `*`	If non-null, the previous id being watched is returned here. Zero if there was none.
<	oldWatchRoutine	SdsWatchRoutineType `*`	If non-null, any old watch routine address is returned here.
<	oldClientData	void `**`	If non-null, any old watch routine client data is returned here.
`!`	status	StatusType*	Modified status.

Function Prototypes Used

typedef void (*SdsWatchRoutineType)(SdsIdType id, void * client_data, int event);

Parameters

(">" input, "!" modified, "W" workspace, "<" output)

>	id	SdsIdType	The `ID` which triggered the watch event.
>	client_data	void `*`	As supplied to SdsSetWatch().
>	event	int	Indicates the event type. The following event types are supported. Others might be added later and code should allow for this.

`SDS_WATCH_EVENT_FREE`	SdsFree or SdsFreeIdAndCheck.
`SDS_WATCH_EVENT_DELETE`	SdsDelete.
`SDS_WATCH_EVENT_READFREE`	SdsReadFree.
`SDS_WATCH_EVENT_NEW`	SdsNew (on parent).
`SDS_WATCH_EVENT_COPY`	SdsCopy.
`SDS_WATCH_EVENT_INSERT`	SdsInsert.
`SDS_WATCH_EVENT_INSERT_CELL`	SdsInsertCell.
`SDS_WATCH_EVENT_EXTRACT`	SdsExtract.
`SDS_WATCH_EVENT_RESIZE`	SdsResize
`SDS_WATCH_EVENT_NEWID`	Any function that creates an id. "id" is the new `SDS` `ID` number.

Support

Tony Farrell, {AAO}

Version date

14-Sep-2004

Click here for the DRAMA home page and here for the AAO home page.

For more information, contact tony.farrell@mq.edu.au