CONTIGUOUS

The CONTIGUOUS attribute can be specified in a type declaration statement or an CONTIGUOUS statement, and takes one of the following forms:

Type Declaration Statement:

type, [att-ls,] CONTIGUOUS [, att-ls] :: object [, object] ...

Statement:

CONTIGUOUS [::] object [, object] ...

type	Is a data type specifier.
att-ls	Is an optional list of attribute specifiers.
object	Is an assumed-shape array or an array pointer.

Description

This attribute explicitly indicates that an assumed-shape array is contiguous or that a pointer will only be associated with a contiguous object.

An entity can be contiguous even if CONTIGUOUS is not specified. An object is contiguous if it is one of the following:

• An object with the CONTIGUOUS attribute

• A nonpointer whole array that is not assumed-shape

• An assumed-shape array that is argument associated with an array that is contiguous

• An array allocated by an ALLOCATE statement

• An pointer associated with a contiguous target

• A nonzero-sized array section in which the following is true:

  • Its base object is contiguous.

  • It does not have a vector subscript.

  • The elements of the section, in array element order, are a subset of the base object elements that are consecutive in array element order.

  • If the array is of type character and a substring-range appears, the substring-range specifies all of the characters of the parent-string.

  • Only its final reference to a structure component, if any, has nonzero rank

  • It is not the real or imaginary part of an array of type complex.

An object is not contiguous if it is an array subobject, and all of the following are true:

• The object has two or more elements.

• The elements of the object in array element order are not consecutive in the elements of the base object.

• The object is not of type character with length zero.

• The object is not of a derived type that has no ultimate components other than zero-sized arrays and characters with length zero.

The CONTIGUOUS attribute can make it easier to enable optimizations that rely on the memory layout of an object occupying a contiguous block of memory.

Examples

The following examples show valid CONTIGUOUS statements:

REAL, CONTIGUOUS, DIMENSION(:,:) :: A
REAL, POINTER, CONTIGUOUS :: MY_POINTER(:)