VMS: logicals UNIX: links, but...

Richard A. O'Keefe ok at quintus.UUCP
Tue Apr 18 07:10:55 AEST 1989


In article <810037 at hpsemc.HP.COM> gph at hpsemc.HP.COM (Paul Houtz) writes:
>ok at quintus.UUCP (Richard A. O'Keefe) writes:
>
>> And what on earth do you think the logical names SYS$INPUT, SYS$OUTPUT,
>>and so on are in VMS?  The VAX-11 C compiler thinks they are stdin, stdout,
>
>Wrong.  Wrong.  Wrong.   The names are similar.  Some of the functionality
>is similar.  But they are NOT stdout and stdin.  Not unless the functionality
>is identical.  You see, Unix stdou and stdin are used a lot by programmers
>because there is a REASON.  You can use them in pipes and you can easily
>redirect them.   There is no such reason on VMS.  So they sound the
>same, but they aint.

Oh well, then, by _that_ criterion *nothing* in VMS has an equivalent in UNIX.
What an easy way to knock down a straw man.  May I respectfully suggest that
before someone claims that VMS hasn't got redirection, they look in the DCL
manual?  Specifically at the RUN command.

Bourne shell:	myprog <source >destination 2>error-log

VMS DCL:	RUN MYPROG /INPUT=SOURCE /OUTPUT=DESTINATION /ERROR=ERROR-LOG

And then of course there is DEC/Shell, but that's another story.  (UNIX is
not the only system with two different CLIs.)

Then again, when you read the Guide to Programming on VAX/VMS (you _did_
read it, didn't you?) you found that Fortran makes it easy to read from
SYS$INPUT (use UNIT=* or omit the unit entirely or use ACCEPT) and write
to SYS$OUTPUT (use UNIT=* or omit the unit entirely or use PRINT or TYPE).
In fact that chunk of the manual explicitly says "A person using your
program can REDIRECT input and output ...".  Then too, LIB$GET_INPUT and
LIB$PUT_OUTPUT encourage you to use SYS$INPUT and SYS$OUTPUT.

Maybe you don't want to call the DCL /INPUT ... facility redirection, but
that's what DEC call it.  And there is no reason why you can't redirect
to a mailbox if that's what takes your fancy.

Stop knocking VMS!  (:-)



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