Command: call_back
  
Platform: 
  WIN32 , Linux
  
Syntax: 
  a = call_back(i)
  
Description: 
  Get a machine address for the Euphoria routine with id number i.
  This address can be used by Windowsystem as a "call-back" address
  when Windows needs to call the routine.
  
Comments: 
  Use routine_id to get a routine id for any Euphoria procedure
  or function.
  
  In this release you can only have one call-back function
  and it must take 4 arguments. 
  
Example Program: 
 see demo\win32\window.ex

See Also: 
  routine_id
  
