Statements Affecting Variables

Intel® Fortran Compiler

Developer Guide and Reference

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ID 767251

Date 3/31/2025

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Statements Affecting Variables

The following table lists statements that are used to declare variables of intrinsic and derived types, to declare new types, and that can affect the value of variables. Statements that declare variables can specify attributes of the variables. Attributes are listed in the table following this one.

Name	Description
ASSOCIATE ^¹	Associates a name (alias) with a data designator or expression that can be used to identify that designator or expression in a block of code.
BYTE	Specifies variables as the BYTE data type; BYTE is equivalent to INTEGER(1).
CHARACTER	Specifies variables as the CHARACTER data type.
COMMON	Defines one or more contiguous areas, or blocks, of physical storage (called common blocks) that can be accessed by any of the scoping units in an executable program.
COMPLEX	Specifies variables as the COMPLEX data type.
DATA	Assigns initial values to variables.
DOUBLE COMPLEX	Specifies variables as the DOUBLE COMPLEX data type, equivalent to COMPLEX(8).
DOUBLE PRECISION	Specifies variables as the DOUBLE-PRECISION real data type, equivalent to REAL(8).
ENUM	Begins the definition of an interoperable enumeration and may give the type a name.
ENUMERATOR	Associates integer values with named constant enumerators.
EQUIVALENCE	Specifies that two or more variables or arrays share the same memory location.
FINAL	Indicates a derived type is finalizable and specifies what its final subroutines are.
IMPLICIT	Specifies the default types for variables and functions.
IMPLICIT NONE	Disables implicit typing in the scope, or requires all external procedures to have explicit interfaces if invoked from the scope.
INTEGER	Specifies variables as the INTEGER data type.
LOGICAL	Specifies variables as the LOGICAL data type.
MAP	Within a UNION statement, delimits a group of variable type declarations that are to be ordered contiguously within memory.
NAMELIST	Declares a group name for a set of variables to be read or written in a single statement.
NULLIFY ^¹	Disassociates a variable with the POINTER attribute (sets it to NULL).
REAL	Specifies variables as the REAL data type.
RECORD	Declares one or more variables of a user-defined structure type.
SEQUENCE	Prevents the compiler from optimizing the storage order of components in a derived type.
STRUCTURE	Defines a new variable type, composed of a collection of other variable types.
TYPE	Defines a new variable type, composed of a collection of other variable types.
UNION	Within a structure, causes two or more maps to occupy the same memory locations.
¹ This is an executable statement.

The following table lists statements that give attributes to variables. Attributes also can be given to variables in their type declaration statement.

Name	Description
ALLOCATABLE	Indicates an entity can be dynamically allocated and deallocated.
ASYNCHRONOUS	Indicates a variable may be used in asynchronous input or output, or asynchronous communication.
AUTOMATIC	Declares a variable on the stack, rather than at a static memory location.
BIND	Indicates a variable or common block can interoperate with a C variable whose name has external linkage.
CODIMENSION	Specifies that an entity is a coarray and indicates its corank and cobounds, if any.
CONTIGUOUS	Indicates an array object is contiguous.
DIMENSION	Specifies that an entity is an array and indicates its rank and bounds.
EXTERNAL	Indicates an entity is an external procedure, a dummy procedure, a procedure pointer, or a block data subprogram.
INTENT	Indicates how a dummy argument is to be used: as an input argument (IN), an output argument (OUT), or as both input and output (INOUT).
INTRINSIC	Indicates an entity is an intrinsic procedure.
OPTIONAL	Indicates a dummy argument need not be associated with an actual argument in a procedure invocation.
PARAMETER	Equates a constant expression with a name.
POINTER	Indicates an entity can be associated with different data objects or procedures during the execution of a program. A pointer is either a data pointer or a procedure pointer, but not both.
PRIVATE	Limits the accessibility of a module entity by a particular name, or that of a component of a derived type declared in a module.
PROTECTED	Specifies limitations on the use of module entities.
PUBLIC	Makes a module entity accessible by USE association, or it makes a component of a derived type declared in a module accessible when the derived type is USE associated.
SAVE	Causes variables to retain their values between invocations of the procedure in which they are defined.
STATIC	Declares a variable is in a static memory location, rather than on the stack.
TARGET	Indicates a data object may become associated with a data pointer.
VALUE	Indicates a dummy argument is passed by value rather than by reference.
VOLATILE	Specifies that the value of an object is totally unpredictable based on information available to the current program unit.

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Statements Affecting Variables