To set a parameter, you send a ``SET'' message with the message name set to the parameter name in the form action:parameter (eg. stats:ndf) and the value field to the desired parameter value. The task will respond with a setresponse message with a status field set to SAI__OK if the parameter was sucessfully set. If not, it will send one of more inform messages containing error messages followed by a setresponse message with a status other than SAI__OK (for example, SUBPAR__NOPAR if the parameter didn't exist). When the task executes the coresponding action it will behave exactly as if the parameter had been set with a command line argument in the ``OBEY'' message.
STARTCL --- Starlink Extensions to Tcl & Tk