Subject: Re: Is there a new tcsh source
To: der Mouse <>
From: Guenther Grau <>
List: current-users
Date: 10/11/1994 15:55:40

I followed the discussion about writing portable programs on current-users.
I don't know if you are interested in this, but I just want to give you
my $0.02 worth :-)

Press 'Delete Mail' now, if you are not interested in it :-)

You're still reading on, fine :-)

> >> In my case, at least, it's simply that there is no header file I can
> >> count on to declare such things for me, so it's either use them
> >> undeclared (which works in only a few instances) or declare them
> >> myself.
> > This is what standards are for.
> Ah, but there are so many standards!  Which one should I use?

You are right here, but there are only a few standards, which I'd
consider important. I think POSIX is _THE_ standard for operating
systems in the future. Almost everybody tries to be POSIX-compliant.

> > Generally, your code should assume a POSIX.1-compliant system
> Why should I pick POSIX.1 as my standard-of-choice, rather than (say)
> traditional BSD, or traditional SysV?  For that matter, where can I
> fetch a description of what "POSIX.1-compliant" means?

IMHO, traditional BSD will stop to exist very soon, SysV, too.
If I remember things correctly, Novell bought the Unix-src from
AT&T and passed the right to call sth. Unix on to X/Open.
The standards from X/Open are the almost same as Posix. X/Open
adopted Posix and the few remaining differences are soon to be removed.
So, if you want to adhere to one standard, choose Posix or XPG4,
which is the current brand for operating systems from X/Open.
There are a lot of books out there on standards. I bought an XPG4
book and it says that things have settled down that way, that they
can announce XPG4, which is essentially POSIX, to be a standard and
to remain unchanged for a long time. It includes all the functions
a proper OS must/may/should provide and describes which headerfiles
have to be included. I admit, that you have to pay a few bucks for
it, but I think it is worth it!!! Whenever I'm in doubt which function
I have to use or how, then I'll fetch the book and the answer is there
in a few minutes. NetBSD is going the POSIX/XPG-way, Linux, too, and
all the commercial Unix-verndors, too, even Windows NT will be POSIX-
compliant. I hope I could make it clear to you, why you should choose
POSIX or X/OPEN. Please don't feel offended by anything I wrote.
I did not try to offend anyone, but my limited knowledge of Englisch
hinders me in expressing my thoughts in the correct way. Everything
I write is just an approximation of what I wanted to express, but I
hope you can understand, what I wanted to say:-)