Usenet 1994 January/usenetsourcesnewsgroupsinfomagicjanuary1994.iso/sources/std_unix/volume.20/text0043.txt

Internet Message Format | 1990-08-02 | 9.0 KB

From:  <[e-mail]>


           An Update on UNIX*-Related Standards Activities

                               May 1990

                 USENIX Standards Watchdog Committee

                   Jeffrey S. Haemer, Report Editor

IEEE 1003.9: FORTRAN bindings

Michael Hannah <[e-mail]> reports on the April 23-27 meeting
in Salt Lake City, UT:

FORTRAN bindings committee prepares to go to ballot

The FORTRAN bindings committee is preparing the official call for a
ballot group.  Because the POSIX work is all done under the auspices
of the IEEE Technical Committee on Operating Systems Standards
Subcommittee (TCOS-SS), all members of the ballot group must be both
regular IEEE or Computer Society members.  and members of the TCOS-SS
(no extra charge to join).  Non-members may submit informative
ballots, but such ballots cannot count towards the required response
percentage (75%), or percentage of affirmative responses (also 75%)
required for passage of the standard.  [Editor: Institutional
Representatives are exceptions to this rule.  See IEEE 1003.1-1988,
p. 177 for a detailed explanation of the rules.]

For more information, the appropriate membership forms, and
instructions for returning the forms to the proper IEEE offices,
contact the committee chair, John McGrory, at the address listed at
the end of this article.  This information/sign-up packet will be
available by the end of June, but you may contact the chair as soon as
you want your name added to the distribution list.

The formal sign-up period is expected to be August 15 through October
19, 1990.  The ballot period is expected to last from November 9, 1990
through January 4, 1991.  We are especially eager to attract a large,
representative balloting group, and encourage interested individuals
to sign up.  While the views represented on the P1003.9 working group
have been appropriate and varied, the number of active members has
been small (typically, around a dozen).

__________

  * UNIX is a registered trademark of AT&T in the U.S. and other
    countries.

May 1990 Standards Update                IEEE 1003.9: FORTRAN bindings


                - 2 -

Some history

As the committee prepares to go to ballot, it might be of value to
review some of the more sticky issues that the working group has
addressed.  The formal, adopted charter of the committee is to provide
access to the POSIX-defined, standard operating system interface and
environment, directly from the FORTRAN language.  There are two major
issues of scope that bear comment: ``Access to how much of POSIX?''
and ``Which FORTRAN?''

Some POSIX features are easily imagined as useful to a FORTRAN
application (e.g., chmod, exec, etc.); some are less easily imagined
(pick your favorite obscure system call).  It was unclear where to
draw the line, so the committee took the attitude of ensuring access
to all features defined in 1003.1 (IEEE 1003.1-1988, or ISO/IEC 9945-
1:1990).  It seemed clear that full functional access would be
provided by most vendors, so full standardization seemed called for.
Some diehard C language addicts continue to ask, ``Why have any
FORTRAN bindings?'' Although most vendors provide a method of calling
C functions from FORTRAN, they vary from vendor to vendor.  Further,
any library of C routines provided by a vendor to map FORTRAN
constructs to the POSIX defined procedures is bound to differ among
vendors.  The P1003.9 bindings are silent on implementation, so the
FORTRAN subprograms defined in the bindings could be implemented as
just such a library.  The bindings just standardize the interface.
Keeping in mind the POSIX goal of application portability, only a
truly complete FORTRAN binding would provide portability of any
FORTRAN application.

A harder issue was, ``Which FORTRAN?'' Our choices were:

  1.  FORTRAN 77 [ANSI X3.9-1978, ISO 1539-1980 (E)],

  2.  a codification of common extensions/enhancements to FORTRAN 77,
      or

  3.  the revised FORTRAN standard emerging from the ANSI X3J3
      committee --  previously referred to as FORTRAN 8X but now
      called Fortran 90.  (The working group has been delighted to
      have an officially appointed representative of X3J3 as an active
      member.) [Editor: Note that Fortran 90 will finally let us type
      the name of the language without using the caps-lock key.  ``And
      gain is gain, however small.''  --  Robert Browning]
We chose the first.

For FORTRAN 77 vs. Fortran 90, we were swayed by the fact that FORTRAN
77 is currently the only adopted standard.  (Fortran 90 is scheduled
to be adopted as an ANSI standard after P1003.9 goes to ballot.)
Further, FORTRAN-77-based applications are expected to exist for some
years.  Thus, the working group felt that FORTRAN-77-based bindings
would be of value to the user community.  The working group expects to

May 1990 Standards Update                IEEE 1003.9: FORTRAN bindings


                - 3 -

develop a new set of bindings, based solely on Fortran 90, after
completion of the FORTRAN 77 bindings (and after the Fortran 90
standard is adopted).  One result of this decision is a subprogram-
naming scheme that reflects the version of the language (e.g., CALL
F77MKDIR(...) ).  This will ensure that there will be no name-space
conflict with similar-purpose subprograms in a future Fortran 90
binding.

An even harder issue, once we decided to base the bindings on FORTRAN
77, was whether to define the bindings as extensions and/or
enhancements to the language itself, or simply as a library of
callable FORTRAN subprograms.  While the latter was finally chosen,
there was considerable argument for the former.  In fact, one
extension to FORTRAN 77 was considered minimally essential.  The
current document requires the language to differentiate external names
unique to 31 characters, even though the FORTRAN 77 standard limits
them to six.  The extension seems harmless.  Fortran 90 specifies
uniqueness to 31 characters and all current FORTRAN 77 compilers
researched provide this extension.  Further, since the list of P1003.9
subprogram names is finite, if necessary, a vendor could provide a
preprocessor to convert these names into unique strings of six
characters.

If the P1003.9 bindings had defined changes to the language itself,
then major missing constructs in the FORTRAN 77 language needed for
easy POSIX access (most notably, structures and pointers) could have
been provided by choosing either the emerging Fortran 90 constructs or
an existing vendor solution.  At first the working group felt that
this might be required for some access features.  However, as we
struggled with each issue, working papers and proposals were
introduced that resolved every one with callable FORTRAN subprograms
(though some might argue about elegance or ease of use).  While we
mostly steered clear of ``ease-of-implementation'' arguments, since we
viewed the FORTRAN 77 bindings as an interim, we felt that vendors
would be quicker to implement a library of subprograms than
modifications to compilers.

A final, hard question of standard scope concerned whether to restrict
the standard to 1003.1, or expand it to general, FORTRAN-application
portability issues, both within and outside the POSIX arena.  Both a
lack of resources and a desire to provide a timely bindings on the
heels of 1003.1 made us decide to limit the scope to 1003.1
functionality.

As other base standards are produced (e.g., 1003.2, 1003.4, etc.), we
expect to construct and ballot bindings for those standards.  For
example, we have worked with P1003.2 in defining a standardized
command to invoke the FORTRAN compiler (after a number of iterations,
now named fort77) which is part of their current draft.  Actual
P1003.9 bindings to 1003.2 might include definitions of additional
utilities of use to FORTRAN applications not mentioned in the base
1003.2 standard (e.g., f77split, f77lint, etc.).

May 1990 Standards Update                IEEE 1003.9: FORTRAN bindings


                - 4 -

Another argument against adding features was that many, if not most,
of the problems we saw in portability are solved by new constructs in
Fortran 90.  Many of us felt that as a standards group we should only
provide a minimum set of features for ``perhaps-soon-to-be-obsolete''
FORTRAN 77, and thereby speed up the date for providing full bindings
to the new Fortran 90, which provides more features for application
portability.

How to get involved

If you have strong feelings about these issues, the most effective
avenue to express them at this point is to join the balloting group
being formed.  Nevertheless, if you wish to discuss them before this
you can also directly contact the chair (John McGrory) or me (vice-
chair, Michael Hannah), or join the e-mail discussion group.
Addresses follow:

P1003.9 Chair
John McGrory
Hewlett Packard Co.
Division 2615
19046 Pruneridge Avenue
Cupertino, Ca 95014
[e-mail]

P1003.9 ViceChair
Michael Hannah
Sandia National Labs
Albuquerque, NM 87185
[e-mail]

Un-moderated mailing list:
[e-mail]
To join the list, send request to:
[e-mail]

May 1990 Standards Update                IEEE 1003.9: FORTRAN bindings

Volume-Number: Volume 20, Number 43