Date: Tue, 10 Feb 1998 13:30:58 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Nate Eldredge <eldredge AT ap DOT net>
cc: djgpp AT delorie DOT com
Subject: Re: Suggestion: Portability section for libc docs
In-Reply-To: <199802100441.UAA02948@adit.ap.net>
Message-ID: <Pine.SUN.3.91.980210133039.12622M-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
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On Mon, 9 Feb 1998, Nate Eldredge wrote:

> Each function could say whether it is ANSI, POSIX, available on Unix
> or other DOS compilers, unique to DJGPP, etc.

I think this is a very good idea.

Two comments:

    1) Since most DOS-based compiler don't have POSIX-compliant
       headers such as unistd.h, I suggest that the Portability
       section would also include the headers where the
       functions/variables are declared in the other DOS compilers.
       This will allow people to write code like below when they need
       e.g. to use `dup2', without looking for Borland docs:

       #ifdef unix
       #include <unistd.h>
       #else
       #include <io.h>
       #endif

    2) Sometimes functions which exist on other platforms have
       slightly different functionality.  In such cases, the
       differences should be mentioned.

> Before everyone gets upset, I am willing to work on this myself. However, I
> don't have the ANSI or POSIX standards and don't have much experience with
> other DOS compilers, other than a very old version of Turbo C. Perhaps
> someone can tell me where I can get (by e-mail or FTP only, please)
> summaries or lists of functions defined by the standards (or even the
> standards themselves, though I gather they cost lots of money :( ).

You don't need the standards, it is enough to look into the DJGPP
headers.  Anything that is before ``#ifndef __STRICT_ANSI__'' is ANSI;
anything that is before ``#ifndef _POSIX_SOURCE'' is POSIX and
non-ANSI; everything that's after ``#ifndef _POSIX_SOURCE'' is neither
ANSI nor POSIX.

I can offer help in Borland-related issues up to BC 3.1; I don't have
and never worked with BC 4.x or 5.x.  I can also access SunOS 4.x
(BSD-like), SunOS 5.x (SysV-like), Alpha/Unix, and Linux systems to
see whether a function is available there.