Re: ISO/IEC 14519 - Ada POSIX binding

[Kilgallen@SpamCop.net (Larry Kilgallen)]

In article <m3he6jsiqi.fsf@insalien.org>, Ludovic Brenta <ludovic.brenta@insalien.org> writes:
> Marin David Condic writes:
> 
>> Ludovic Brenta wrote:

>> > On the contrary, as I said, POSIX _is_ an abstract interface, and
>> > implementations have some freedom in how they implement it.
>> >
>> It is an "abstract interface" for a UNIX-like implementation. There
>> are OS's besides UNIX and possibly in the next ten years or so that
>> an Ada standard would have to live, there may be a bunch more
>> non-UNIX operating systems out there. I have no objection to POSIX
>> or UNIX - just suggesting that an Ada standard would do well to not
>> dictate either POSIX or UNIX as the only possible answer.
> 
> Maybe you have a point here ("all problems can be solved with an
> additional level of indirection", I think was the quote).  It probably
> depends on how difficult it would be to implement POSIX.5 sockets on
> non-POSIX platforms.

It is not just a matter of "how difficult" but rather "how illogical".
VMS direct IP access uses the QIO system service which returns status
on every call and after every IO completion.  Layering a C-language
socket structure on top of that introduces the awful "errno" business.
Now should an IP package for Ada go through that C-language layer and
try to undo the "errno" business, or should it call the QIO system service
directly and never get tied up in "errno" at all ?

> Furthermore, I would think that anyone designing
> a new OS in the next ten years would want to make it POSIX-compliant,
> because it would be too difficult to try an impose an alternative API.
> In fact, you've probably noticed that even the MVS and z/OS mainframe
> operating systems became POSIX-compliant for just that reason.

When VMS added Posix-compliant calls it was to allow C programmers
to use it in a fashion to which they were accustomed.  They did
_not_ force all programmers to use those C conventions.  Is the
MVS situation somehow more restrictive ?