HP Fortran Programmer's Reference (September 2007)

Intrinsic procedures

Basic terms and concepts

Chapter 11504

NOTE Some compile-line options—for example, +autodbl—change the default data

type sizes and can cause different or invalid intrinsic procedure references.

Classes of intrinsics

Intrinsic procedures are classiﬁed as:

• Elemental intrinsics

• Transformational functions

• Inquiry functions

The following sections describe each class. The descriptions in “Intrinsic procedure

speciﬁcations” on page 514 identify the class of each intrinsic.

Elemental intrinsics

An intrinsic procedure is elemental if it is speciﬁed as having scalar arguments but will actual

arguments that are arrays. Calling an elemental intrinsic with an array argument causes the

function to perform the scalar operation on each element of the array. MVBITS is the only

elemental subroutine. All other intrinsic subroutines are nonelemental.

An elemental function that is called with all scalar dummy arguments delivers a scalar result.

Calling an elemental function with conformable array arguments, however, results in a

conformable array result. If both array and scalar arguments are speciﬁed to an elemental

function, each scalar is treated as an array in which all elements have the scalar value. The

“scalar array” is conformable with the array arguments.

Transformational functions

Transformational intrinsic functions are nonelemental. Such functions require at least one

array argument and return either a scalar or array result based on actual arguments that

cannot be evaluated elementally. Often, an array result will be of a different shape than the

argument(s). For example, SUM returns a scalar result that represents the sum of all the

elements of the array argument.

Inquiry functions

Inquiry intrinsic functions return information based on the properties of the principal

argument—its value is irrelevant, and the argument need not be deﬁned. For example, the

SIZE inquiry function can be used to return the extent of an array along one dimension or the

total number of elements in the array.