The END statement must appear as the last statement of every
program unit. It simply consists of the word:
END
which may not be followed by any continuation lines (or comments). The
END statement is executable and may have a label attached. If an
END statement is executed in a subprogram unit, i.e. a procedure,
it returns control to the calling unit; if an END statement is
executed in the main program it closes any files which are open, stops
the program, and returns control to the operating system.