function: set up names for semaphore files, which are used to mark the start and end of
program execution; in action mode, create a semaphore on demand.
sequence: must precede run_setup.
Command syntax, including use of equations and subcommands, is discussed in 7.2.
started — Gives the (incomplete) filename of a file to create when a valid run_setup
command is given.
done — Gives the (incomplete) filename of a file to create when the program exits without
error. If the file exists, it is deleted when a valid run_setup command is given.
failed — Gives the (incomplete) filename of a file to create when the program exits with an
error. If the file exists, it is deleted when a valid run_setup command is given.
immediate — If given, the named file is immediately created. This can be used to synchronize
another process with an elegant run. Other parameters are ignored.