XtManageChildren(Xt)

Syntax

typedef Widget *WidgetList;
void XtManageChildren(children, num_children)
WidgetList children;
Cardinal num_children;

void XtManageChild(child)
Widget child;

void XtUnmanageChildren(children, num_children)
WidgetList children;
Cardinal num_children;

void XtUnmanageChild(child)
Widget child;

Arguments

child

Specifies the child.

children

Specifies a list of child widgets.

num_children

Specifies the number of children.

Description

• Issues an error if the children do not all have the same parent or if the parent is not a subclass of compositeWidgetClass.

• Returns immediately if the common parent is being destroyed; otherwise, for each unique child on the list, XtManageChildren ignores the child if it already is managed or is being destroyed and marks it if not.

• If the parent is realized and after all children have been marked, it makes some of the newly managed children viewable:

• Calls the change_managed routine of the widgets' parent.

• Calls XtRealizeWidget on each previously unmanaged child that is unrealized.

• Maps each previously unmanaged child that has map_when_managed True.

Managing children is independent of the ordering of children and independent of creating and deleting children. The layout routine of the parent should consider children whose managed field is True and should ignore all other children. Note that some composite widgets, especially fixed boxes, call XtManageChild from their insert_child procedure.

If the parent widget is realized, its change_managed procedure is called to notify it that its set of managed children has changed. The parent can reposition and resize any of its children. It moves each child as needed by calling XtMoveWidget, which first updates the x and y fields and then calls XMoveWindow if the widget is realized.

The XtManageChild function constructs a WidgetList of length one and calls XtManageChildren.

The XtUnmanageChildren function performs the following:

• Issues an error if the children do not all have the same parent or if the parent is not a subclass of compositeWidgetClass.

• Returns immediately if the common parent is being destroyed; otherwise, for each unique child on the list, XtUnmanageChildren performs the following:

  • Ignores the child if it already is unmanaged or is being destroyed and marks it if not.

  • If the child is realized, it makes it nonvisible by unmapping it.

• Calls the change_managed routine of the widgets' parent after all children have been marked if the parent is realized.

XtUnmanageChildren does not destroy the children widgets. Removing widgets from a parent's managed set is often a temporary banishment, and, some time later, you may manage the children again.

The XtUnmanageChild function constructs a widget list of length one and calls XtUnmanageChildren.

See also

X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface