An interrupt provides a method of forcing a process to depart from its current point of control and to execute the unlabeled statement that the INTERRUPT declaration associates with the interrupt.

After executing the unlabeled statement associated with an interrupt, a program usually returns to its previous point of control. However, the program does not return to this point if a GO TO statement is executed within the unlabeled statement and the specified designational expression references a statement outside of the unlabeled statement.

Once an interrupt is declared, it is enabled until it is explicitly disabled with the DISABLE statement. The DISABLE statement can temporarily render the associated interrupt ineffective. The ENABLE statement is used to reenable a disabled interrupt.

For an interrupt to be used, the interrupt identifier must be attached to an event through the ATTACH statement. An interrupt can be detached from an event through the DETACH statement.

An INTERRUPT declaration can be thought of as describing an unlabeled statement, which can be a block, that is automatically entered on the occurrence (CAUSE) of an event. The operating system ensures that when a program is executing the unlabeled statement associated with an interrupt, all other interrupts are queued until the program exits the unlabeled statement.

For more information, refer to ATTACH Statement, DETACH Statement, DISABLE Statement, and ENABLE Statement.