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The Scope of Variables
Variable names must be unique in their scope. The EQUEL/Fortran preprocessor understands scoping of variables if your program adheres to the following rules:
To declare a scope for a program or subprogram, use the ## signal on the program, subroutine or function statement line and also on the line where the matching end statement appears. EQUEL considers the scope of variables declared in such a program or subprogram to be exactly that program unit. The variables can be local variables, common variables or subprogram dummy arguments (formal parameters).
Be aware that without scoping information, the preprocessor considers the declare and declare forms statements to signal the closing of the previous scope and the opening of a new one. In other words, if your program has not used the ## signal on a program, subroutine or function statement, a declare statement begins a new scope. For a discussion of the EQUEL/Fortran declare statement, see The Declare and Declare Forms Statements.
The following program fragments illustrate the scope of variables in an EQUEL/Fortran program:
## program emp
## declare

C The following two declarations will be visible to the
C preprocessor until the end of program 'emp'.

## integer empid
## real empsal
## real raise

C EQUEL statements using 'empid', 'empsal' and 'raise'

       call prcemp (empid)
       call prcsal (empsal, raise)
## end

## subroutine prcemp (empid)
## declare
C 'empid' must be redeclared to EQUEL because of new 
C  scope

## integer empid

C EQUEL statements using 'empid'

## end

## subroutine prcsal (esal, raise)
## declare

C Declare only those formal parameters to EQUEL that
C will be used in EQUEL statements.

## real esal

C EQUEL statements using 'esal'

## end
Last modified date: 06/10/2024