hpux man page for xtorderproc

XtOrderProc()															     XtOrderProc()

Name
  XtOrderProc - interface definition for an XtNinsertPosition procedure.

Synopsis
  typedef Cardinal (*XtOrderProc)(Widget);
	 Widget w;

Inputs
  w	    Specifies the widget.

Description
  An XtOrderProc is registered as the value of the XtNinsertPosition resource of a composite widget, and is called by some subclasses of Com-
  posite to determine the position in the Composite children array at which a newly created child should be inserted.

  An XtOrderProc should return the position in the array at which w should be inserted.  A return value of zero means that it should  be  the
  first  widget  in the array, a return value of one means that there should be one widget before it in the array, and so on.  A return value
  equal to the XtNnumChildren resource indicates that the widget should be placed at the end of  the  array,  which  is  the  default  if  no
  XtOrderProc is registered.

Usage
  Note that for many composite widgets, the position of a child in the children array has nothing to do with its position on the screen.  The
  XtNinsertPosition resource will only be interesting if the widget does not provide any other method of positioning its children.

  The Composite class insert_child() method calls the XtOrderProc, if any, registered on the XtNinsertPosition resource.  Most composite sub-
  classes inherit or call this procedure explicitly and will therefore do the same.

  Note	that  the XtNinsertPosition procedure is not a method of the widget class.  It could be considered an "instance method" rather than a
  "class method."  In this way it is similar to the procedure that can be registered on the XtNcreatePopupChildProc resource of a shell  wid-
  get.

Example
  None	of  the  standard  MIT	clients make use of the XtNinsertPosition resource.  An example of where an XtOrderProc might be useful is an
  application that dynamically creates a number of button widgets (to represent mail folders or newsgroups, perhaps) and  places  them	in  a
  simple  Xaw  Box  widget.  Since these buttons will differ from user to user, and can be inserted and deleted during a session, it would be
  logical to place them in alphabetical order.	An XtOrderProc could do this by using XtGetValues() to get the current list of	widget	chil-
  dren, and then comparing the name (using XtName()) of the specified widget against the names of all the existing widgets.

See Also
  Composite(3),
  delete_child(4), insert_child(4).

Xt - Geometry Management													     XtOrderProc()