Locator variables

Because a locator variable identifies the location of any generation, you can refer at any point in a program to any generation of a based variable by using an appropriate locator value.

The following example declares that references to X, except when the reference is explicitly qualified, use the locator variable P to locate the storage for X.

  dcl X fixed bin based(P);

The association of a locator reference in this way is not permanent. The locator reference can be used to identify locations of other based variables and other locator references can be used to identify other generations of the variable X. When a based variable is declared without a locator reference, any reference to the based variable must always be explicitly locator-qualified.

In the following example, the arrays A and C refer to the same storage. The elements B and C(2,1) also refer to the same storage.

  dcl A(3,2) character(5) based(P),
      B char(5) based(Q),
      C(3,2) character(5);
  P = addr(C);
  Q = addr(A(2,1));

Note: When a based variable is overlaid in this way, no new storage is allocated. The based variable uses the same storage as the variable on which it is overlaid (C(3,2) in the example).