control block
A statement block which executes when a certain condition (the activation
clause), becomes true. In 4GL, control blocks like BEFORE FIELD, AFTER INPUT, AFTER
CONSTRUCT, and ON KEY occur in the user interaction statements; in this
context they are often called form management blocks. Control blocks also occur in
the FORMAT section of a report, including PAGE HEADER, AFTER GROUP OF, and ON
EVERY ROW.
See also activation key, report, statement block, user interaction statements.