To get a parameter value, send a ``GET'' message with the parameter in the message name field; the task will respond with a getresponse message with the name set to the parameter name and with the parameter's value in the value field. Errors are handled in the same way as for a ``SET''. The ``GET'' message is only really useful if the task is running with its type set to ``I'', otherwise all of an actions parameters are annulled (set to have no value) when an action completes.
STARTCL --- Starlink Extensions to Tcl & Tk