Data Object Declarations and Specifications

The Cray Fortran compiler accepts the following extensions to declarations.

The Cray Fortran compiler accepts the following extensions to declarations. The maximum rank is equal to 31. The standard requires a maximum rank of 15.

BOZ Constraints in DATA Statements

The Cray Fortran compiler permits a default real object to be initialized with a BOZ, typeless, or character (used as Hollerith) constant in a DATA statement. BOZ constants are formatted in binary, octal, or hexadecimal. No conversion of the BOZ value, typeless value, or character constant takes place.

The Cray Fortran compiler permits an integer object to be initialized with a BOZ, typeless, or character (used as Hollerith) constant in a type declaration statement. The Cray Fortran compiler also allows an integer object to be initialized with a typeless or character (used as Hollerith) constant in a DATA statement.

If the last item in the data_object_list is an array name, the value list can contain fewer values than the number of elements in the array. Any element that is not assigned a value is undefined.

The following alternate forms of BOZ constants are supported:


`literal-constant`	is	`typeless-constant`
`typeless-constant`	is	`octal-typeless-constant`
`octal-typeless-constant`	is	`digit` `digit`... B
	or	" `digit` `digit`... "O
	or	' `digit` `digit`... 'O
`hexadecimal-typeless-constant`	is	X' `hex-digit` `hex-digit`... '
	or	X" `hex-digit` `hex-digit`... "
	or	' `hex-digit` `hex-digit`... 'X
	or	" `hex-digit` `hex-digit`... "X

The Cray Fortran AUTOMATIC attribute specifies stack-based storage for a variable or array. Such variables and arrays are undefined upon entering and exiting the procedure. The following is the format for the AUTOMATIC specification:

type, AUTOMATIC  , attribute-list  :: entity-list


`automatic-stmt`	is	AUTOMATIC :: `entity-list`

entity-list

For entity-list, specify a variable name or an array declarator. If an entity-list item is an array, it must be declared with an explicit-shape-spec with constant bounds. If an entity-list item is a pointer, it must be declared with a deferred-shape-spec.

If an entity-list item has the same name as the function in which it is declared, the entity-list item must be scalar and of type integer, real, logical, complex, or double precision.

If the entity-list item is a pointer, the AUTOMATIC attribute applies to the pointer itself and not to any target that may become associated with the pointer.

Subject to the rules governing combinations of attributes, attribute-list can contain the following:

DIMENSION
TARGET
POINTER
VOLATILE

The following entities cannot have the AUTOMATIC attribute:

Pointers or arrays used as function results
Dummy arguments
Statement functions
Automatic array or character data objects

An entity-list item cannot have the following characteristics:

It cannot be defined in the scoping unit of a module.
It cannot be a common block item.
It cannot be specified more than once within the same scoping unit.
It cannot be initialized with a DATA statement or with a type declaration statement.
It cannot also have the SAVE or STATIC attribute.
It cannot be specified as a Cray pointee.

IMPLICIT Statement

Implicit Extensions: The Cray Fortran compiler accepts the IMPLICIT AUTOMATIC or IMPLICIT STATIC syntax. It is recommended that none of the IMPLICIT extensions be used in new code.

Storage Association of Data Objects

EQUIVALENCE Statement Extensions: The Cray Fortran compiler allows equivalencing of character data with noncharacter data. The Fortran standard does not address this. It is recommended that equivalencing is not performed in this manner, however, because alignment and padding differs across platforms, thus rendering the code less portable.

The Cray Fortran compiler treats named common blocks and blank common blocks identically, as follows:

Variables in blank common and variables in named common blocks can be initialized.
Named common blocks and blank common are always saved.
Named common blocks of the same name and blank common can be of different sizes in different scoping units.