Writing a SCOadmin manager

Processing errors

To catch an error caused by an operation, a procedure must call the operation indirectly by using ErrorCatch(3tlib). This is similar to using catch(1tcl), but ErrorCatch allows you to manage the error stack. If the error is serious enough to stop processing, you can add additional information to the error stack by calling ErrorPush with the error ID that describes the error.

Template sample code: ErrorCatch/Push

if {[ErrorCatch stack 0 [list CallNonStdCmd $cmd $args $errId] data]} {
	ErrorPush stack 0 [IntlErrId WHO_UNABLE]
	UiDisplayErrorStacks WhoGetData $stack
	return {}

UiDisplayErrorStacks uses SaDisplayErrorStacks(3tlib) to display an error box showing the top level error text from the stack. It provides a Details button for viewing the complete stack. The Details dialog also provides a Save button for logging the error stack to a file for future reference. An optional Help button can be included where relevant help attachments are available.

Template procedure: SaDisplayErrorStacks

proc UiDisplayErrorStacks {caller stack {callback ""}} {
	global appvals

	if {$appvals(autorefresh)} {
		SaAutoRefreshPause
	}
	SaDisplayErrorStacks $appvals(vtMain).$caller [list $stack] HELP \
		[list UiDisplayErrorStackCB $callback]
}

SaDisplayErrorInfo provides for displaying a simple text string rather than a fully formed error stack. It creates a standard stack which contains the topErrorText and then calls SaDisplayErrorStacks. This results in consistent error presentation regardless of its source.