42.3. $newException

$newException returns a STRING consisting of a unique decimal integer followed by a colon. The STRING may be concatenated to the front of another STRING describing an exception to produce a unique exception name, or may be used as an exception name by itself. To avoid conflicts with names created in these ways, users should avoid choosing an exception name that begins with a decimal integer and a colon unless that prefix was obtained by calling $newException.

Values returned by $newException may vary from execution to execution of the same program.