Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide

Execute command for dependents (!)

Syntax: ! command

The exclamation-point command modifier causes the command to be executed for each dependent file if the command uses one of the special macros $? or $**. The $? macro refers to all dependent files out-of-date with respect to the target. The $** macro refers to all dependent files in the description block.

See Special macros.

Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide