coyote: GET_OBJECT_ID

NAME
GET_OBJECT_ID
PURPOSE
The purpose of this function is to be able to obtain a unique
object identifier string for a heap variable (object or pointer).
AUTHOR
FANNING SOFTWARE CONSULTING
David Fanning, Ph.D.
1645 Sheely Drive
Fort Collins, CO 80526 USA
Phone: 970-221-0438
E-mail: david@idlcoyote.com
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
CATEGORY
Utility.
CALLING SEQUENCE
objectID = Get_Object_ID(theObject)
INPUTS
theObject:    The object or pointer for which an identifier is requested. If
              this is a null object, the function returns the string
              "NullObject". If it is a null pointer, "NullPointer". 
OUTPUTS
objectID:     The unique object or pointer identifier.
KEYWORDS
NUMBER:       If this keyword is set, the function returns the unique
              number identifier associated with a valid pointer or object.
              The number is returned as a STRING variable. The string 
              "-999" is returned if the pointer or object is invalid and
              this keyword is set.
EXAMPLE
Create a trackball object and obtain its unique object ID.
   IDL> theObject = Obj_New('TRACKBALL', [100,100], 50)
   IDL> objectID = Get_Object_ID(theObject, NUMBER=number)
   IDL> Print, objectID
           ObjHeapVar71(TRACKBALL)
   IDL> Print, number
           71
MODIFICATION HISTORY
Written by: David W. Fanning, 4 September 2003.
Added NUMBER keyword. DWF, 22 September 2008.