SAVE Attribute

The SAVE attribute can be:

• applied to a specified variable. In the following example, NumInvocations is initialised only on the first call (conceptually at program start-up) and then retains its new value between calls,

      SUBROUTINE Barmy(arg1,arg2)
       INTEGER, SAVE :: NumInvocations = 0
        NumInvocations = NumInvocations + 1

• applied to the whole procedure by appearing on a line on its own. This means that all local objects are SAVE d.

      SUBROUTINE polo(x,y)
       IMPLICIT NONE
       INTEGER :: mint, neck_jumper
       SAVE
       REAL :: stick, car

In the above example mint, neck_jumper, stick and car all have the SAVE attribute.

Variables with the SAVE attribute are known static objects and have static storage class.

In fact, the SAVE attribute is given implicitly if an object, which is not a dummy argument or a PARAMETER, appears in an initialising declaration in a procedure, so

    INTEGER, SAVE :: NumInvocations = 0

is equivalent to

    INTEGER :: NumInvocations = 0

however, the former is clearer!

Clearly, the SAVE attribute has no meaning in the main program since when it is exited, the program has finished executing.

Objects appearing in COMMON blocks or DATA statements are automatically static.

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