Volume 7A: XView Programming Manual

NOTE

The X protocol restricts an unmapped window from holding the input focus.

Another way to grab keyboard focus for a window is to grab all the input for that window.

This can be accomplished in various ways, including the use of the FULLSCREEN package

described in Chapter 15, Nonvisual Objects. However, a much more convenient method is to

use the WIN_GRAB_ALL_INPUT attribute. Setting this attribute to TRUE causes a grab that

forces all input to be directed to that window. Setting it to FALSE releases the grab.

This is useful when you want to display a dialog box having panel items and confirmation or

cancel buttons that the user must respond to before interacting with any other portion of the

application. In this case, you should set the grab on the panel. Be sure to reset this attribute

once it is no longer needed. Also, be careful when you code the segment of the program that

uses the grab, or you might generate a grab you cannot get out of.

6.6.1.3 Selection events

Selection events may be delivered to a window’s event procedure if the window owns a

selection or is making selection requests. Generally, these events should be ignored if the

application is using XView’s

SELECTION package. If the application is doing its own selec-

tions by calling Xlib functions directly, then these events will be of interest.

6.7 Interpreting Client Messages

Client messages may be delivered to your event handler for a variety of reasons. For

instance, the event may have been sent by another source using XSendEvent() ...