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14. Main program

14. Main program

The main program is where execution begins. Every executable program has exactly one (§14).

      PROGRAM PAYROLL
      ...
      END
  • The PROGRAM statement, if present, is the first statement and names the program. The name is documentation; it has no other use. The PROGRAM line is optional — a unit with no header that isn't a FUNCTION/SUBROUTINE/BLOCK DATA is the main program.
  • A main program may contain any statements except FUNCTION, SUBROUTINE, BLOCK DATA, ENTRY, or RETURN — it is not a procedure and is never called.
  • Reaching the main program's END (or executing a STOP) terminates the program.

That is the whole of it; the substance of a program lives in its statements (earlier chapters) and its subprograms (Chapter 15).

forterp notes. PROGRAM is optional and, when present, named, exactly as specified; execution starts at the main program's first executable statement regardless of where the unit appears in the source.