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=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,6b7062ec13fd16a9,start
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2001-12-04 06:01:13 PST
Path: 
 archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.online.be!195.129.110.18.MISMATCH!bnewspeer00.bru.ops.eu.uu.net!bnewsifeed00.bru.ops.eu.uu.net!bnewsifeed01.bru.ops.eu.uu.net!bnewspost00.bru.ops.eu.uu.net!emea.uu.net!read.news.de.uu.net!not-for-mail
Message-ID: <3C0CD717.F720A1DB@meppen.sema.slb.com>
Date: Tue, 04 Dec 2001 15:00:55 +0100
From: Vincent Smeets <VSmeets@meppen.sema.slb.com>
Organization: CCI - SchlumbergerSema
X-Mailer: Mozilla 4.77 [en] (X11; U; SunOS 5.6 sun4m)
X-Accept-Language: nl, en, de
MIME-Version: 1.0
Newsgroups: comp.lang.ada
Subject: Abort of C-code in a asynchronous_select
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
NNTP-Posting-Host: zerberus.cci.de
X-Trace: 1007474456 read.news.de.uu.net 187 193.103.165.100
X-Complaints-To: abuse@de.uu.net
Xref: archiver1.google.com comp.lang.ada:17381
Date: 2001-12-04T15:00:55+01:00
List-Id: <comp.lang.ada>

Hallo,

I have a driver for reading and writing data written in C. The
C-routines are protected with a semaphores against being called by two
threads at the same time. The code can't be changed.

I want to call the blocking C-Driver.Read routine from Ada but must be
able to abort the call in case of an application state change. I was
thinking of the statements:

select
   State.Not_Active;
then abort
   C_Driver.Read (Data, Data_Last);
end select;

I am assuming that in case the Read-call is aborted, the semaphore in C
isn't freed because C doesn't know anything about the Ada-abort. Am I
correct and how can I do it better?

-- 
Vincent Smeets
SchlumbergerSema -
Competence Center Informatik GmbH 
Lohberg 10 - 49716 Meppen - Germany
tel:  +49 5931-805-461
fax:  +49 5931-805-175
mail: VSmeets@slb.com
web:  www.cci.de