Convert Dec-Fortran from VMS to DEC-UNIX 
Author Message
 Convert Dec-Fortran from VMS to DEC-UNIX

Hello,

Is it difficult, much work, to convert a program written in VAX-fortran
to Fortran under DEC-Unix.
We change our System from VMS 6 AXP to DEC-UNIX 3.0.

Thanx in advance

JR _________________________________________________________________________

  | Jochen Ruckgaber, SYSOP and DBA    |  its for fighting and for wars !!  |
  | University of Ulm, Nuclear Medicine|                                    |
  | Robert-Koch-Str. 8                 |               YES, 90125           |
  | 89060 Ulm / Germany                |                                    |
  | Tel.: 49+ 731/502-4510             |    If it don't fits,               |
  | Fax.: 49+ 731/502-4503             |         use a bigger hammer !!!    |
  \___________________________________/ \___________________________________/



Sun, 17 May 1998 03:00:00 GMT  
 Convert Dec-Fortran from VMS to DEC-UNIX

Quote:

>Is it difficult, much work, to convert a program written in VAX-Fortran
>to Fortran under DEC-Unix.

No, just unfortunate.  I haven't had many problems doing the conversion myself.
The only real nuisance I found was that VMS Fortran allows common blocks and
subroutines to have the same name, whereas Unix Fortran does not.
One thing you will really miss though is the VMS de{*filter*}, which is infinitely
superior to Unix's dbx.

Peter.



Sun, 17 May 1998 03:00:00 GMT  
 Convert Dec-Fortran from VMS to DEC-UNIX
Quote:

>Is it difficult, much work, to convert a program written in VAX-Fortran
>to Fortran under DEC-Unix.
>We change our System from VMS 6 AXP to DEC-UNIX 3.0.

It depends on what your program does.  If the program calls VMS routines
(SYS$, LIB$, etc.), then you will either need to rewrite those sections
of code or use a VMS emulation library like the one we offer.  If the program
depends on indexed files, you would again either need to do significant
rewriting, or else use a tool like the FORTRAN precompiler which we offer.
By the way, indexed file support is provided in the FORTRAN compilers on
some Unix variants...Digital decided not to support this feature, for
whatever reason (one DEC engineer told me that his assumption was that
dependency on indexed files is a dependency on VMS rather than a dependency
on a VAX FORTRAN feature).  There are a number of other possible porting
issues, for example the need to redeclare as INTEGER*8 any variables
which need to hold memory addresses (Digital Unix is 64-bit).  It might
be worthwhile to pick up a copy of DEC's "Open VMS and DEC OSF/1
Interoperability Guide", which is Digital part number EC-N3399-43.  It
discusses a lot of the potential issues.  I hope this is useful, please
let me know if you have any questions about anything I've said.
--



Mon, 18 May 1998 03:00:00 GMT  
 Convert Dec-Fortran from VMS to DEC-UNIX


|>
|>>Is it difficult, much work, to convert a program written in VAX-Fortran
|>>to Fortran under DEC-Unix.
|>
|>No, just unfortunate.  I haven't had many problems doing the conversion myself.
|>The only real nuisance I found was that VMS Fortran allows common blocks and
|>subroutines to have the same name, whereas Unix Fortran does not.
|>One thing you will really miss though is the VMS de{*filter*}, which is infinitely
|>superior to Unix's dbx.

The restriction on COMMON block names comes from the UNIX linker for which
COMMON blocks and routine names share the same namespace.  However, the
Fortran standard also prohibits any two "global" objects from sharing a name,
so you are better off to make them separate for the sake of portability.

You may find that the decladebug de{*filter*} is an improvement over dbx, though
I also find the OpenVMS de{*filter*} to be superior.

We've worked very hard at making DEC Fortran for Digital UNIX as compatible
as possible with the OpenVMS VAX compiler.  The one problem I see most often
doing this port is where the VAX program erroneously passes single precision
values to routines expecting double precision.  On VAX, this seems to work
as the default double type has the same layout in the first 32 bits as
the single type.  On Alpha systems, the default double type doesn't have the
same layout, so you get wrong answers or other errors.  The Alpha compilers
have an "argument checking" warning switch that will detect many such
problems.

Another issue is if the VAX program uses OpenVMS system services and
run-time library routines.  These would have to be recoded to use UNIX
library routines.  Compiling on VAX with /WARN=ULTRIX will point out use
of features not implemented on our UNIX compilers.

I'd be glad to answer questions on this subject - send me mail or post here
(though I won't be reading the newsgroup for the next week as I'll be at
DECUS.)
--


DEC Fortran Development           WWW:   http://www.*-*-*.com/
Digital Equipment Corporation     CompuServe: 75263,3001
110 Spit Brook Road, ZKO2-3/N30
Nashua, NH 03062-2698             "Free advice is worth every cent"

For information on DEC Fortran 90, see http://www.*-*-*.com/



Mon, 18 May 1998 03:00:00 GMT  
 Convert Dec-Fortran from VMS to DEC-UNIX
: Hello,

: Is it difficult, much work, to convert a program written in VAX-Fortran
: to Fortran under DEC-Unix.
: We change our System from VMS 6 AXP to DEC-UNIX 3.0.

I've been transfering own programs from VMS to DEC-UNIX and did not have any
problem. Seemingly, the compilers under both systems support the same
extensions vs. FORTRAN 77 (you even have full F90 under DEC-UNIX). Mind you,
if your programs make use of calls to the VMS system library, you may get
in trouble (I have no idea whether the names used in both systems are the
same, neither do I know whether the same calls are supported at all!)

Some stuff depending on the OS will work differently also, as there is
command line editing and recall (which I failed to get for DEC-UNIX).

I'm sure there's somebody around with more experience concerning this matter!

Hope this already helps a bit,

Andre

: Thanx in advance

: JR _________________________________________________________________________

:   | Jochen Ruckgaber, SYSOP and DBA    |  its for fighting and for wars !!  |
:   | University of Ulm, Nuclear Medicine|                                    |
:   | Robert-Koch-Str. 8                 |               YES, 90125           |
:   | 89060 Ulm / Germany                |                                    |
:   | Tel.: 49+ 731/502-4510             |    If it don't fits,               |
:   | Fax.: 49+ 731/502-4503             |         use a bigger hammer !!!    |
:   \___________________________________/ \___________________________________/



Tue, 19 May 1998 03:00:00 GMT  
 
 [ 5 post ] 

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