Block Activation Numbers

Activation numbers pertain to only recursive procedures and to languages that allow recursive procedures.

A procedure is active when it has been called during program execution. Each new call to a procedure counts as a new activation. The activation number specifies a unique activation of a procedure when more than one activation exists. Multiple activations occur when a procedure is recursive (A calls A) or indirectly recursive (A calls B calls A). Activation numbers are either absolute or relative.