The ENABLE AST command enables the delivery of ASTs while your
    program is running, including any pending ASTs (ASTs waiting
    to be delivered). If ASTs are delivered while the debugger is
    running (processing commands, and so on), they are queued and are
    delivered when control is returned to the program. Delivery of
    ASTs in your program is initially enabled by default.

                                   NOTE

       Any call by your program to the $SETAST system service that
       disables ASTs overrides a previous ENABLE AST command.

    Related commands:

       (DISABLE,SHOW) AST