Specifications

Athena Widget Set libXaw 1.0.7

2.7. Processing Events

Nowthat the application has created, managed and realized its widgets, it is ready to process the

ev e nts that will be delivered by the X Server to this client. Afunction call that will process the

ev e nts is XtAppMainLoop.

void XtAppMainLoop(app_context)

XtAppContext app_context;

app_context Speciﬁes the application context of this application. The value is normally

returned by XtAppInitialize.

This function neverreturns: it is an inﬁnite loop that processes the X events. User input can be

handled through callback procedures and application deﬁned action routines. More details are

provided in XToolkit Intrinsics — C Language Interface.

2.8. Standard Widget Manipulation Functions

After a widget has been created, a client can interact with that widget by calling one of the stan-

dard widget manipulation routines provided by the Intrinsics, or a widget class-speciﬁc manipula-

tion routine.

The Intrinsics provide generic routines to give the application programmer access to a set of stan-

dard widget functions. The common widget routines let an application or composite widget per-

form the following operations on widgets without requiring explicit knowledge of the widget

type.

•Control the mapping of widget windows

•Destroyawidget instance

•Obtain an argument value

•Set an argument value

2.8.1. Mapping Widgets

By default, widget windows are mapped (made viewable) automatically by XtRealizeWidget.

This behavior can be disabled by using XtSetMappedWhenManaged,making the client respon-

sible for calling XtMapWidget to makethe widget viewable.

void XtSetMappedWhenManaged(w, map_when_managed)

Widget w;

Boolean map_when_managed;

w Speciﬁes the widget.

map_when_managed

Speciﬁes the newvalue. If map_when_managed is True,the widget is mapped

automatically when it is realized. If map_when_managed is False,the client

must call XtMapWidget or makeasecond call to XtSetMappedWhenMan-

aged to cause the child windowtobemapped.

The deﬁnition for XtMapWidget is:

void XtMapWidget(w)

Widget w;

w Speciﬁes the widget.

When you are creating several children in sequence for a previously realized common parent it is

generally more efﬁcient to construct a list of children as theyare created (using XtCreateWidget)

and then use XtManageChildren to request that their parent managed them all at once. By man-

aging a list of children at one time, the parent can avoid wasteful duplication of geometry pro-

cessing and the associated ‘‘screen ﬂash’’.