Path: utzoo!mnetor!uunet!husc6!mit-eddie!ll-xn!ames!pacbell!att-ih!ihnp4!inuxc!iuvax!pur-ee!uiucdcs!uxc.cso.uiuc.edu!uxe.cso.uiuc.edu!hirchert
From: hirchert@uxe.cso.uiuc.edu
Newsgroups: comp.lang.fortran
Subject: Re: F8X response, MODULE vs. INCLUD
Message-ID: <50500031@uxe.cso.uiuc.edu>
Date: 9 Mar 88 19:01:00 GMT
References: <5714@ames.arpa>
Lines: 24
Nf-ID: #R:ames.arpa:5714:uxe.cso.uiuc.edu:50500031:000:1374
Nf-From: uxe.cso.uiuc.edu!hirchert    Mar  9 13:01:00 1988


There appears to be some confusion about the implementation implications of
MODULE/USE:
1. If you don't make use of MODULE/USE, then your program should be
   independently compilable just as it was in FORTRAN 77.
2. Even if you do use MODULE/USE, it should remain possible to separately
   compile the various program units in your program.
3. The dependency introduced by MODULE/USE is essentially equivalent to that
   introduced by the INCLUDE statement:  To compile a program unit containing
   an INCLUDE statement, you must first make the information available by
   putting it in a file with the appropriate name.  To compile a program
   containing a USE statement, you must first make the information available
   by compiling the MODULE being referenced.
4. Properly implemented, MODULE/USE should be faster than INCLUDE because it
   bypasses the need to repeatedly convert textually represented information
   into the form it is used internally by the compiler.  (This is analogous
   to the fact that unformatted input/output is faster than formatted
   input/output.)

I do not consider INCLUDE an adequate replacement for MODULE/USE.  I would not
object to having INCLUDE in addition to MODULE/USE, but most people seem to
object to the redundancy inherent in that kind of combination.

Kurt W. Hirchert      National Center for Supercomputing Applications