SAVE

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

Type Declaration Statement:

type,[att-ls,] SAVE [, att-ls] :: entity[, entity ] ...

Statement:

SAVE [[::]entity [, entity ] ...]

type	Is a data type specifier.
att-ls	Is an optional list of attribute specifiers.
entity	Is the name of an object, the name of a procedure pointer, or the name of a common block enclosed in slashes (/common-block-name/).

Description

In Intel® Fortran, certain variables are given the SAVE attribute, or not, by default:

• The following variables are not saved by default:

  • Scalar local variables of intrinsic types INTEGER, REAL, COMPLEX, and LOGICAL without default initialization

  • Variables that are declared AUTOMATIC

  • Local variables that are allocatable arrays

  • Derived-type variables that are data initialized by default initialization of any of their components

  • RECORD variables that are data initialized by default initialization specified in its STRUCTURE declaration

• The following variables are saved by default:

  • COMMON variables

  • Scalar local variables not of intrinsic types INTEGER, REAL, COMPLEX, and LOGICAL of non-recursive subprograms

  • Non-scalar local variables of non-recursive subprograms

  • Module or submodule variables

  • Data initialized by DATA statements

• Local variables that are not described in the preceding two lists are saved by default.

To enhance portability and avoid possible compiler warning messages, Intel recommends that you use the SAVE statement to name variables whose values you want to preserve between subprogram invocations.

When a SAVE statement does not explicitly contain a list, all allowable items in the scoping unit are saved.

A SAVE statement cannot specify the following (their values cannot be saved):

• A blank common

• An object in a common block

• A procedure

• A dummy argument

• A function result

• An automatic object

• A PARAMETER (named) constant

Even though a common block can be included in a SAVE statement, individual variables within the common block can become undefined (or redefined) in another scoping unit.

If a common block is saved in any scoping unit of a program (other than the main program), it must be saved in every scoping unit in which the common block appears.

A SAVE statement has no effect in a main program.

Example

The following example shows a type declaration statement specifying the SAVE attribute:

SUBROUTINE TEST()
  REAL, SAVE :: X, Y

The following is an example of the SAVE statement:

SAVE A, /BLOCK_B/, C, /BLOCK_D/, E

The following shows another example:

  SUBROUTINE MySub
    COMMON /z/ da, in, a, idum(10)
    real(8) x,y
    ...

    SAVE x, y, /z/
! alternate declaration
    REAL(8), SAVE :: x, y
    SAVE /z/