At the suggestion of Craig Markwardt, all the routines (except the service routine POINTER_SETGETV5) work under IDL5 and IDL4, allowing for easier porting from IDL4 to IDL5. It is also possible to create or free an array of pointers.

POINTER_CREATE: Create a single pointer, or an array of pointers.

This routine mimics the behavior of PTR_NEW (IDL5) and HANDLE_CREATE (IDL4). Differences include:
- Written as a procedure instead of a function. This allows the input argument to be checked to see if it's already a valid pointer. If it is a valid pointer, the pointer is freed and then re-created (this helps to avoid dangling references).
- Does not accept any keywords (HANDLE_CREATE accepts the keywords FIRST_CHILD, NO_COPY, SIBLING, and VALUE).
Examples:
IDL> pointer_create, ptr
IDL> help, ptr
IDL> pointer_create, ptr, npointers=10
IDL> help, ptr

POINTER_FREE: Free a single pointer, or an array of pointers.

This routine mimics the behavior of PTR_FREE (IDL5) and HANDLE_FREE (IDL4).
Example:
IDL> pointer_create, ptr
IDL> pointer_free, ptr

POINTER_VALID: Check a single variable to see if it is a valid pointer.

This routine mimics the behavior of PTR_VALID (IDL5) and HANDLE_INFO (IDL4). Differences include:
- Does not accept any keywords (HANDLE_INFO accepts the keywords FIRST_CHILD, NUM_CHILDREN, PARENT, SIBLING, VALID_ID).
Example:
IDL> pointer_create, ptr
IDL> help, pointer_valid(ptr)

POINTER_VALUE: Set or get the value of a single pointer.

(Requires the service routine POINTER_SETGETV5)
This routine mimics the behavior of the dereference operator * (IDL5) and HANDLE_VALUE (IDL4).
Example:
IDL> pointer_create, ptr
IDL> pointer_value, ptr, dist(256), /set
IDL> pointer_value, ptr, val
IDL> help, val

With the aid of these routines, all I needed to do to convert handles to pointers was:
(1) Convert function calls to HANDLE_CREATE to procedure calls to POINTER_CREATE,
(2) Globally replace all remaining instances of 'handle' to 'pointer'.
Please let me know if you have any comments, suggestions, or questions.