4.3.2 The HALT condition The HALT condition of external origin, which is raised as a result of an action from the user, normally a combination of keys which tries to abort the program. Which combination of keys will vary between operating systems. Some systems might also simulate this event by other means than key combinations. Consult system for more information. The differences between HALT and the standard condition are: · The default-action for the HALT condition is to abort execution, as though a REXX runtime error number 4 (Program interrupted) had been reported. But note that SYNTAX will never be raised if HALT is not trapped. · The delay-action of this condition is to ignore, not queue. The standard allows the interpreter to limit the search for situations that would set the HALT condition, to clause boundaries. As a result, the response time from pressing the key combination to actually raising the condition or triggering the trap may vary, even if HALT is trapped by method SIGNAL. If a clause for some reason has blocked execution, and never finish, you may not be able to break the program. The descriptive text returned by CONDITION() when called with the Description option for condition HALT, is implementation dependent, and may also be a nullstring. In general, it will describe the way in which the interpreter was attempted halted, in particular if there are more than one way to do raise a HALT condition. Consult the implementation documentation for more information.