FORTRAN Reference Manual

Statements

FORTRAN Reference Manual—528615-001

7-36

EQUIVALENCE Statement

The EQUIVALENCE statement defines the sharing of storage space by two or more

entities in a program unit.

var-list

is a comma-separated list of variable names array names, array element names,

character substring names, or RECORD names.

Considerations

•

The compiler assigns the same storage location to all entities in var-list. If the

equivalenced items are of different data types, the EQUIVALENCE statement does

not cause type conversion nor imply mathematical equivalence.

•

Equivalencing specifies that all entities in var-list share the same first storage

word. For character entities, equivalencing specifies that all entities in the list share

the same first character storage position.

•

If var-list includes an array element, the number of subscript expressions must

be the same as the number of dimensions declared for that array. An

unsubscripted array name in an EQUIVALENCE statement implicitly specifies that

equivalencing begin with the first element of that array.

•

Subscript expressions, and substring expressions used in var-list must be

integer constant expressions.

•

Observe the following restrictions with the EQUIVALENCE statement:

var-list cannot contain names of external procedures, dummy arguments,

or variable names that are also function names.

You cannot use the EQUIVALENCE statement to assign the same storage

location to more than one element of the same array.

You cannot equivalence an entity of character type to an item of any other data

type.

You can equivalence RECORDs only to other RECORDs. For additional

information, see the Records on page 2-20.

EQUIVALENCE ( var-list) [, ( var-list) ]...