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XtManageChildren(3)


NAME

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


SYNTAX

       #include <X11/Intrinsic.h>

       typedef Widget *WidgetList;

       void XtManageChildren(WidgetList children, Cardinal num_children);

       void XtManageChild(Widget child);

       void XtUnmanageChildren(WidgetList children, Cardinal num_children);

       void XtUnmanageChild(Widget child);

       void XtChangeManagedSet(WidgetList unmanage_children, Cardinal
              num_unmanage_children, XtDoChangeProc do_change_proc, XtPointer
              client_data, WidgetList manage_children, Cardinal num_man-
              age_children);

       Boolean XtIsManaged(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 man-
                 aged set.

       num_unmanage_children
                 Specifies the number of entries in the unmanage_children
                 list.

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

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


DESCRIPTION

       The XtManageChildren function performs the following:

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

       o    Returns immediately if the common parent is being destroyed; oth-
            erwise, 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.

       o    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_man-
                 aged True.

       Managing children is independent of the ordering of children and inde-
       pendent 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, espe-
       cially fixed boxes, call XtManageChild from their insert_child proce-
       dure.

       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:

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

       o    Returns immediately if the common parent is being destroyed; oth-
            erwise, for each unique child on the list, XtUnmanageChildren per-
            forms 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.

       o    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:

       o    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.

       o    Returns immediately if the common parent is being destroyed.

       o    If no CompositeClassExtension is defined, or a CompositeClassEx-
            tension is defined but with an allows_change_managed_set field
            with a value of False, and XtChangeManagedSet was invoked with a
            non-NULL do_change_proc procedure then XtChangeManagedSet performs
            the following:

            -    Calls XtUnmanageChildren (unmanage_children, num_unman-
                 age_children).

            -    Calls the do_change_proc specified.

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

       o    Otherwise, if a CompositeClassExtension is defined with an
            allows_change_managed_set field with a value of True, or if no
            CompositeClassExtension is defined, and XtChangeManagedSet was
            invoked with a NULL do_change_proc procedure, then the following
            is performed:

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

            -    If the do_change_proc procedure 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, oth-
                 erwise it is marked as managed

       o    If the parent is realized and after all children have been marked,
            the change_managed method of the parent is invoked and subse-
            quently 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 other-
       wise.


SEE ALSO

       XtMapWidget(3), XtRealizeWidget(3)
       X Toolkit Intrinsics – C Language Interface
       Xlib - C Language X Interface



X Version 11                     libXt 1.1.5.2             XtManageChildren(3)