Language Reference

Intrinsic Procedures

An intrinsic procedure is a procedure already defined by XL Fortran. See Chapter 12, Intrinsic Procedures for details.

You can reference some intrinsic procedures by a generic name, some by a specific name, and some by both:

A generic intrinsic function

does not require a specific argument type and usually produces a result of the same type as that of the argument, with some exceptions. Generic names simplify references to intrinsic procedures because the same procedure name can be used with more than one type of argument; the type and kind type parameter of the arguments determine which specific function is used.

A specific intrinsic function

requires a specific argument type and produces a result of a specific type.

A specific intrinsic function name can be passed as an actual argument. If a specific intrinsic function has the same name as a generic intrinsic function, the specific name is referenced. All references to a dummy procedure that are associated with a specific intrinsic procedure must use arguments that are consistent with the interface of the intrinsic procedure.

Whether or not you can pass the name of an intrinsic procedure as an argument depends on the procedure. You can use the specific name of an intrinsic procedure that has been specified with the INTRINSIC attribute as an actual argument in a procedure reference.

• An IMPLICIT statement does not change the type of an intrinsic function.
• If an intrinsic name is specified with the INTRINSIC attribute, the name is always recognized as an intrinsic procedure.

Conflicts Between Intrinsic Procedure Names and Other Names

Because intrinsic procedure names are recognized, when a data object is declared with the same name as an intrinsic procedure, the intrinsic procedure is inaccessible.

A generic interface block can extend or redefine a generic intrinsic function, as described in Interface Blocks. If the function already has the INTRINSIC attribute, it is extended; otherwise, it can be redefined.