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=3.8 required=5.0 tests=BAYES_00,INVALID_MSGID,
	RATWARE_MS_HASH,RATWARE_OUTLOOK_NONAME autolearn=no autolearn_force=no
	version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,5d05ccde5cefb836
X-Google-Attributes: gid103376,public
From: "Jerry van Dijk" <jvandyk@ibm.net>
Subject: Re: Tasks and C/C++ code.
Date: 1998/11/12
Message-ID: <01be0dd2$aaff3da0$0100007f@aptiva>#1/1
X-Deja-AN: 410914289
References: <364702E5.F6987321@hiwaay.net> <729ndu$jfo$1@nnrp1.dejanews.com>
 <72b35b$pll$1@nnrp1.dejanews.com> <3649A4C4.4D3D22A2@hiwaay.net>
X-Notice: should be reported to postmaster@ibm.net
X-Complaints-To: postmaster@ibm.net
X-Trace: 12 Nov 1998 01:14:19 GMT, 139.92.162.214
Organization: JerryWare
Newsgroups: comp.lang.ada
Date: 1998-11-12T00:00:00+00:00
List-Id: <comp.lang.ada>

> So, if I understand correctly defining the pragma to C in the declaration
part of
> the task body will give me multiple binding to the same function if there
are
> multiple tasks?

This is still confused.

Forget about tasks for the moment.

If you call a C function it will be in some C library. Therefore, there is
only one
copy of this function, namely the one in this C library.

The question whether or not this C function is thread (task) safe, depends
on
how the function is written. Consult the documentation or source code of
the 
function to find out. 

All this has absolutely nothing to do with either Ada or Tasking, only with
C.

Now think about tasking again.

Every task that generates a _call_ to this C function will address only
this
single function in this specific library. Ada is not about to generate C
functions
for you!

So, if the C function you want to use is not thread (task) safe, you need
to make
sure that it is only accessed by a single task at the time. One of the
solutions
is to put the C function call in a separate task.

-- 
-- Jerry van Dijk | Leiden, Holland
-- Team Ada       | email: jdijk@acm.org
-- Ada & Win32: http://stad.dsl.nl/~jvandyk