WtLoop Procedure

PV-WAVE Foundation > Reference Guide > Procedure and Function Reference: W > WtLoop Procedure

WtLoop Procedure

Handles the dispatching of events and calling of callback routines.

Usage

WtLoop

Parameters

None.

Returned Value

None.

Keywords

Noblock — If specified and nonzero, events are dispatched in the background, and WtLoop returns immediately to process PV‑WAVE commands from the command line.

Discussion

WtLoop causes PV‑WAVE to loop indefinitely, processing the events and dispatching callbacks, handlers, and timers.

note

Rogue Wave has ported a subset of the Widget Toolbox (Wt) functionality that is available for Motif to Microsoft Windows. Because the Widget Toolbox under Windows is not a complete implementation, we recommend that Windows developers use the PV‑WAVE Widgets (Ww) layer or the VDA Tools when developing GUI applications.

For interapplication development using cwavec() or cwavefor(), the default behavior of WwLoop is to block, even if the Noblock keyword is set. To force nonblocking, set Noblock = 2 and then call WtProcessEvent periodically to service the event loop.

Motif Example

This example creates a Motif button labeled Done.

PRO example

   COMMON block, top

   @wtxmclasses.pro

   top=WtInit('wt_ex4', 'Examples')

   widget=WtCreate('Done', xmPushButtonWidgetClass, top)

   status=WtAddCallback(widget, 'activateCallback', $

      'CancelHelp')

   status=WtSet(top, /Realize)

   WtLoop

END