The FUNCTION-POINTER phrase defines an item as a function-pointer data item. A function-pointer data item can contain the address of a procedure entry point.
A function-pointer is a 4-byte elementary item. Function-pointers have the same capabilities as procedure-pointers, but are 4 bytes in length instead of 8 bytes. Function-pointers are thus more easily interoperable with C function pointers.
A function-pointer can contain one of the following addresses or can contain NULL:
A VALUE clause for a function-pointer data item can contain only NULL or NULLS.
A function-pointer can be used in the same contexts as a procedure-pointer, as defined in PROCEDURE-POINTER phrase.