From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,8ebde0e81efb7e79
X-Google-Attributes: gid103376,public
From: Matthew Heaney <matthew_heaney@acm.org>
Subject: Re: Importing a Unix function call
Date: 1998/12/06
Message-ID: <m3ogph5b2p.fsf@mheaney.ni.net>#1/1
X-Deja-AN: 419372627
Sender: matt@mheaney.ni.net
References: <36683FA3.2512DECF@ndirect.co.uk> <m33e6t7hqk.fsf@mheaney.ni.net>
 <74e7t5$2deg$1@news.gate.net>
NNTP-Posting-Date: Sun, 06 Dec 1998 11:22:43 PDT
Newsgroups: comp.lang.ada
Date: 1998-12-06T00:00:00+00:00
List-Id: <comp.lang.ada>

"David Botton" <dbotton@hotmail.com> writes:

> Since in Ada non-scalar types are passed by reference (ie as pointers) to C
> functions you could get rid of the Access type and treat it just like C:

The file descriptor array is an out parameter.  The solution you propose
makes the array an in parameter.

I think this is another example of the fact that value-returning
subprograms (which we spell F-U-N-C-T-I-O-N in Ada) should be allowed to
have in out parameters.  

Clearly, what we want is the function

  function Pipe (Files : out File_Descriptor_Array) return Int;

but we can't express this thought using the language.