See the following topics:

• IDL and System Routines Pre-IDL 8.0
• IDL and System Routines Post-IDL 8.0
• System Routine Interface
• Example: Hello World
• Example: MULT2
• Example: Using Routine Design Iteration (RSUM)
• Registering Routines
• Enabling and Disabling System Routines
• Adding System Routines with LINKIMAGE
• DLMs