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=-0.9 required=5.0 tests=BAYES_00,FORGED_GMAIL_RCVD,
	FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: a07f3367d7,d8ff1403929a72c0
X-Google-Attributes: gida07f3367d7,public,usenet
X-Google-NewGroupId: yes
X-Google-Language: ENGLISH,ASCII-7-bit
Received: by 10.66.88.168 with SMTP id bh8mr1479477pab.10.1344322802267;
        Tue, 07 Aug 2012 00:00:02 -0700 (PDT)
Path: 
 p10ni243pbh.1!nntp.google.com!npeer03.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!border3.nntp.dca.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!ctu-peer!ctu-gate!news.nctu.edu.tw!usenet.stanford.edu!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail
From: awdorrin <awdorrin@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: Interfacing between Ada and C: records and structs
Date: Tue, 31 Jul 2012 11:44:11 -0700 (PDT)
Organization: http://groups.google.com
Message-ID: <5813d3d2-8a9f-4a08-bf09-db3c62847593@googlegroups.com>
References: <296e271a-967b-4dfb-8dca-f278ecfae03d@googlegroups.com>
 <a7qi6qFoc3U1@mid.individual.net>
NNTP-Posting-Host: 192.91.173.36
Mime-Version: 1.0
X-Trace: posting.google.com 1343760594 18753 127.0.0.1 (31 Jul 2012 18:49:54
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Tue, 31 Jul 2012 18:49:54 +0000 (UTC)
In-Reply-To: <a7qi6qFoc3U1@mid.individual.net>
Complaints-To: groups-abuse@google.com
Injection-Info: glegroupsg2000goo.googlegroups.com;
 posting-host=192.91.173.36;
 posting-account=YkFdLgoAAADpWnfCBA6ZXMWTz2zHNd0j
User-Agent: G2/1.0
X-Received-Bytes: 2736
Content-Type: text/plain; charset=ISO-8859-1
Date: 2012-07-31T11:44:11-07:00
List-Id: <comp.lang.ada>

On Tuesday, July 31, 2012 1:16:10 PM UTC-4, Niklas Holsti wrote:
> 
> How is pthread_mutex_t declared in Ada form? And in C form?
> 

Digging into the POSIX module:

private
  type Dummy is tagged null record;
  type Mutex is record
    Mutex : aliased POSIX.C.pthread_mutex_t;
    D : Dummy;
  end record

> 
> Have you checked that in Ada, pthread_mutex_t'Size is 192?
> 

In the POSIX.C package:
ALIGNMENT : constant := Natural'Min(Standard'Maximum_Alignment, 8);
type pthread_mutex_t'Alignment use ALIGNMENT;
type pthread_mutex_t'Size use 192;

However, when I write a simple test program I get 256 bits from 'Size, I'm not sure why...
But that is probably the source of my problem.
 
> 
> What is the storage unit of your target processor? 8 bits?

The system is an Intel core2Duo E4600 - so a 64bit processor running x86_64 variant of Debian. (32-bit mode) So the storage unit is 8 bits.

> 
> That is a strange alignment. Do you see any need for it? If not, try
> removing it.

That was a typo on my part, should have read 'Alignment use 8;

> 
> Do you see any need for this representation clause? If not, remove it.
> 
> Or change it to use 192 bits per component.

That is the output from the -gnatR3 parameter, I don't have the rep spec defined in the code.

> 
> (What are the "-" characters after the "at" keywords? Shouldn't it read
> "at 0 range"?)

Sorry, that was apparently another typo on my part. (Cut and paste isn't working between my Linux VNC session and my desktop Windows PC)