The equation part causes the simple variable being declared to have the same address as the simple variable associated with the second identifier. This action is called address equation. An identifier can be address-equated only to a previously declared local identifier or to a global identifier. The first identifier must not have been previously declared within the block of the equation part. An equation part is not allowed in the global part of a program.

Address equation is allowed only between INTEGER, REAL, and BOOLEAN variables. Because both identifiers of the equation part have the same address, altering the value of either variable affects the value of both variables. For more information, see Type Coercion of One-Word and Two-Word Operands.

The OWN specification has no effect on an address-equated identifier. The first identifier of an equation part is OWN only if the second identifier of the equation part is OWN.