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XtManageChildren(3Xt)		XT FUNCTIONS		XtManageChildren(3Xt)



NAME
  XtManageChildren, XtManageChild, XtUnmanageChildren, XtUnmanageChild,
  XtChangeManagedSet, XtIsManaged - manage and unmanage children

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;

  void XtChangeManagedSet(unmanage_children, num_unmanage_children,
  manage_children, num_manage_children, post_unmanage_pre_manage_hook,
  client_data)
	WidgetList unmanage_children;
	Cardinal num_unmanage_children;
	WidgetList manage_children;
	Cardinal num_manage_children;
	XtCSMProc post_unmanage_pre_manage_hook;
	XtPointer client_data;

  Boolean XtIsManaged(widget)
	Widget widget

ARGUMENTS

  child	    Specifies the child.

  children  Specifies a list of child widgets.

  num_children
	    Specifies the number of children.

  widget    Specifies the widget.

  manage_children
	    Specifies the list of widget children to add to the managed set.

  num_manage_children
	    Specifies the number of entries in the manage_children list.

  unmanage_children
	    Specifies the list of widget children to remove from the managed
	    set.

  num_unmanage_children
	    Specifies the number of entries in the unmanage_children list.

  post_unmanage_pre_manage_hook
	    Specifies the post unmanage, pre manage hook procedure to invoke.

  client_data
	    Specifies the client data to be passed to the hook precedure.

DESCRIPTION
  The XtManageChildren 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; other-
       wise, 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 indepen-
  dent 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; other-
       wise, for each unique child on the list, XtUnmanageChildren performs
       the following:

       -    Ignores the child if it already is unmanaged or is being des-
	    troyed 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.

  The XtChangeManagedSet function performs the following:

  +    Issues an error if the widgets specified in the manage_children and
       the unmanage_children lists to no all have the same parent, or if that
       parent is not a subclass of compositeWidgetClass.

  +    Returns immediately if the common parent is being destroyed.

  +    If no CompositeClassExtension is defined, or a CompositeClassExtension
       is defined but with an allows_change_managed_set field with a value of
       False, and XtChangeManagedSet was invoked with a non-NULL
       post_unmanage_pre_manage_hook procedure then XtChangeManagedSet per-
       forms the following:

       -    Calls XtUnmanageChildren (unmanage_children,
	    num_unmanage_children).

       -    Calls the post_unmanage_pre_manage_hook specified.

       -    Calls XtManageChildren (manage_children, num_manage_children) and
	    then returns immediately.

  +    Otherwise, if a CompositeClassExtension is defined with an
       allows_change_managed_set field with a value of True, or if no Compo-
       siteClassExtension is defined, and XtChangeManagedSetwas
       post_unmanage_pre_manage_hook procedure, then the following is per-
       formed:

       -    For each child on the unmanage_children list; if the child is
	    already unmanaged or is being destroyed it is ignored, otherwise
	    it is marked as being unmanaged and if it is realized it is made
	    nonvisible by being unmapped.

       -    If the post_unmanage_pre_manage_hook procdedure is non-NULL then
	    it is invoked as specified.

       -    For each child on the manage_children list; if the child is
	    already managed or it is being destroyed it is ignored, otherwise
	    it is marked as managed

  +    If the parent is realized and after all children have been marked, the
       change_managed method of the parent is invoked and subsequently some
       of the newly managed children are made viewable by:

       -    Calling XtRealizeWidget on each of the previously unmanaged child
	    that is unrealized.

       -    Mapping each previously unmanaged child that has map_when_managed
	    True.

  The XtIsManaged function returns True if the specified widget is of class
  RectObj or any subclass thereof and is managed, or False otherwise.

SEE ALSO
  XtMapWidget(3Xt), XtRealizeWidget(3Xt)
  X Toolkit Intrinsics - C Language Interface
  Xlib - C Language X Interface








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