220 3276 <514DE38D.2060605@wanadoo.fr> article Path: news.gmane.org!not-for-mail From: "Vicente J. Botet Escriba" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: interest in is_recursive_mutex type trait Date: Sat, 23 Mar 2013 18:17:01 +0100 Lines: 138 Approved: news@gmane.org Message-ID: <514DE38D.2060605@wanadoo.fr> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="------------020300010208080507060104" X-Trace: ger.gmane.org 1364059022 8234 80.91.229.3 (23 Mar 2013 17:17:02 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 23 Mar 2013 17:17:02 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDH67CONY4PBBDWHW6FAKGQEDCCDANY@isocpp.org Sat Mar 23 18:17:27 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-bk0-f70.google.com ([209.85.214.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UJS4M-0003Ed-10 for gclcip-std-proposals@m.gmane.org; Sat, 23 Mar 2013 18:17:26 +0100 Original-Received: by mail-bk0-f70.google.com with SMTP id jk7sf7140472bkc.5 for ; Sat, 23 Mar 2013 10:17:02 -0700 (PDT) X-Received: by 10.180.106.161 with SMTP id gv1mr1542523wib.4.1364059022403; Sat, 23 Mar 2013 10:17:02 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.89.243 with SMTP id br19ls2288883wib.50.canary; Sat, 23 Mar 2013 10:17:02 -0700 (PDT) X-Received: by 10.205.40.202 with SMTP id tr10mr2986868bkb.24.1364059021956; Sat, 23 Mar 2013 10:17:01 -0700 (PDT) Original-Received: from smtp.smtpout.orange.fr (smtp06.smtpout.orange.fr. [80.12.242.128]) by mx.google.com with ESMTP id ha11si2248116bkc.161.2013.03.23.10.17.01; Sat, 23 Mar 2013 10:17:01 -0700 (PDT) Received-SPF: neutral (google.com: 80.12.242.128 is neither permitted nor denied by best guess record for domain of vicente.botet@wanadoo.fr) client-ip=80.12.242.128; Original-Received: from iMac-de-Vicente-Botet-Escriba.local ([81.53.182.67]) by mwinf5d63 with ME id F5H11l00B1TfKdt035H1bk; Sat, 23 Mar 2013 18:17:01 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:17.0) Gecko/20130307 Thunderbird/17.0.4 X-Original-Sender: vicente.botet@wanadoo.fr X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 80.12.242.128 is neither permitted nor denied by best guess record for domain of vicente.botet@wanadoo.fr) smtp.mail=vicente.botet@wanadoo.fr Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:3276 Archived-At: This is a multi-part message in MIME format. --------------020300010208080507060104 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hi, The user could require that the mutex passed to an algorithm is a recursive one. E.g. providing a io thread safe service needs a recursive mutex. If the mutex type is a template parameter it would be great if a compile time error is provided when the provided mutex is not recursive. Whether a lockable is recursive or not can not be checked using template meta-programming and is something that the developer states "sur parolle". This is the motivation for the following trait. template class is_recursive_mutex: false_type; // EXTENSION template<> class is_recursive_mutex: true_type; // EXTENSION template<> class is_recursive_mutex: true_type; The trait |is_recursive_mutex| is |false_type| by default and is specialized for the provide |recursive_mutex| and |timed_recursive_mutex|. It should be specialized by the user providing other model of recursive mutexes; e.g. null_mutex. Is there an interest on this trait for the standard? Best regards, Vicente P.S. A similar trait is_recursive_mutex_sur_parolle is already included in Boost.Thread. -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/?hl=en. --------------020300010208080507060104 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi,

The user could require that the mutex passed to an algorithm is a recursive one. E.g. providing a io thread safe service needs a recursive mutex. If the mutex type is a template parameter it would be great if a compile time error is provided when the provided mutex is not recursive.

Whether a lockable is recursive or not can not be checked using template meta-programming and is something that the developer states "sur parolle". This is the motivation for the following trait. 

    template<typename L>
    class is_recu=
rsive_mutex: false_type; // EXTENSION
    template&=
lt;>
    class is_recu=
rsive_mutex<recursive_mutex>: true_type; // EXTENSION
    template&=
lt;>
    class is_recu=
rsive_mutex<timed_recursive_mutex>: true_type;
    
    
 The trait is_recursive_mutex
      is false_ty=
pe
      by default and is specialized for the provide recursive_mutex=

      and timed_r=
ecursive_mutex.
    

    
 It should be specialized by the user providing other model of
      recursive mutexes; e.g. null_mutex.

    

    
Is there an interest on this trait for the standard?

    

    
Best regards,

      Vicente

    

    
P.S. A similar trait is_recursive_mutex_sur_parolle is already
      included in Boost.Thread.

    

  





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