RXTRCTST tests for an external trace indicator.
When called: When the interpreter polls for an external trace event. The exit is called after completion of every REXX instruction.
Default action: None.
Exit Action: Return the current state of external tracing (either TRUE or FALSE).
Continuation: When the exit handler switches from FALSE to TRUE, the REXX interpreter enters REXX interactive debug mode using TRACE ?R level of tracing. When the exit handler switches from TRUE to FALSE, the REXX interpreter exits interactive debug mode.