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-Thread: a07f3367d7,4215feeab2a8154a X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!news1.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!newsfeed00.sul.t-online.de!t-online.de!news.buerger.net!aioe.org!not-for-mail From: John McCabe Newsgroups: comp.lang.ada Subject: Re: C++0x and Threads - a poor relation to Ada's tasking model? Date: Wed, 12 Aug 2009 13:25:00 +0100 Organization: Aioe.org NNTP Server Message-ID: References: <7q2385104kihs87d79p8kfphuoki6r01vq@4ax.com> <7961a91c-a5af-40e2-bbc0-6bf69a98176d@z31g2000yqd.googlegroups.com> NNTP-Posting-Host: RXEkuaSUwmKe0XIGFYSK7A.user.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org X-Notice: Filtered by postfilter v. 0.7.9 X-Newsreader: Forte Agent 2.0/32.652 Cancel-Lock: sha1:kzbHxNOuvthuZer+9PrGmeqkWJs= Xref: g2news2.google.com comp.lang.ada:7694 Date: 2009-08-12T13:25:00+01:00 List-Id: On Tue, 11 Aug 2009 13:51:35 -0700 (PDT), Maciej Sobczak wrote: >On 11 Sie, 17:30, John McCabe wrote: <..snip..> >> So, are we seeing something arriving in C++ that need only be >> supported by implementations running on a 3rd party OS > >Absolutely not, see above. There is nothing that prevents vendors from >implementing stand-alone run-times. Actually, with the API that is >borrowed from *existing implementations* (read: maturity, industrial >experience, etc.), implementing such a stand-alone run-time is >actually much easier than being forced to work with API that is >constructed in isolation from the existing practise. >You might even pick a source code from the Linux kernel and build on >that. Why not? This is the comfort that Ada vendors did not have. >> or will threads need to be supported for bare machines >> as well? >No standard can force anybody to provide implementations. Vendors will >do it if they will see a business opportunity in it. My point/question really was whether it will be acceptable for a C++ compiler to NOT support the threading library (i.e. if a vendor chooses not to provide a bare board run-time system with built in threading). I think you've got the gist of the question, but you've split it in to two when it's only really one question. >> This may seem like a C++ question, but it's >> more a question of "why will Ada's threading model remain vastly >> superior"! >Why do you think it is "vastly superior"? It is certainly more >complex, but the most visible effect of complexity is the cost (both >in time and money) of implementation and this is where we come back to >what you have stated at the beginning - the complexity of run-time has >*hurt* Ada heavily at the beginning and the consequences of it are >still visible in low adoption of the language. > >Being complex does not guarantee higher expressiveness, either. It seems to me that Ada's model started off with a clean slate and was designed from the ground up whereas with C++ it's always been a case of "how can we bolt this on". That's primarily what I was getting at. As I mentioned earlier I've not read a huge amount about this yet, but I've seen little evidence that there are any standards proposed in C++ to handle thread priorities, dispatching policies and so on.