- Boost - lists.boost.org

[thread] to std:: or not to std::
by Michael Caisse 27 Dec '12

27 Dec '12

There seems to be a trend to migrate boost::thread to std::thread. Has there been consideration that perhaps the user community may not want this? There are differing opinions on threads (obviously) and recent breaking changes concern me. For example, the thread destructor now calling terminate instead of detach has made the upgrade to 1.52 more troublesome than it should have been. Will the next move be to remove interruption points? We have purposely selected Boost.Thread on a few projects that are also using C++11 because we prefer the Boost.Thread behaviour and feature set. The purpose of this email isn't to debate the merit of the Boost.Thread feature set but instead to understand the future direction of the library. Can Vicente or someone provide the intended road map or general plan for the library? Thanks! michael -- Michael Caisse ciere consulting ciere.com

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Patch for functional/hash
by Thomas Heller 27 Dec '12

27 Dec '12

Hi, Attached is a patch for functional/hash. The first chunk essentially gets rid of some UB (the same technique was already applied for the remainder so this looks like an oversight). I don't remember why exactly i added the second chunk, it helps on some compilers though (I think gcc on Android). Save to apply that patch? Regards, Thomas

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[proposal] safe_ref<T>
by Fernando Pelliccioni 27 Dec '12

27 Dec '12

Hi all, The motivation is to avoid code like the following... //---------------------------------------------------------------------------- #include <iostream> #include <string> struct A { void do_something( std::string s ) const { std::cout << "do something with " << s << " and " << i_ << "\n"; } int i_ = 99; }; // unsafe traditional code struct Unsafe { void set_ref( A& a ) { a_ptr_ = std::addressof(a); } void use_ref( std::string s ) const { if (a_ptr_ != nullptr) { a_ptr_->do_something(s); } } void use_ref_2( std::string s ) const { //forgot to check for nullptr a_ptr_->do_something(s); } A* a_ptr_ = nullptr; //I can't use A& nor reference_wrapper<A>, need to be nullable. }; void f() { A a; Unsafe unsafe; unsafe.use_ref( "hello" ); //null reference, do nothing, hope! unsafe.set_ref(a); unsafe.use_ref( "hello world!" ); //not-null reference, Ok! Unsafe unsafe2; unsafe2.use_ref( "hello" ); //null reference, do nothing, hope! unsafe2.use_ref_2( "hello" ); //null reference, Ops! } //---------------------------------------------------------------------------- The proposed solution: //---------------------------------------------------------------------------- // Proposed (draft) //---------------------------------------------------------------------------- template <typename T> class safe_ref { public: typedef T type; explicit safe_ref() : t_( nullptr ) {} explicit safe_ref(T& t) : t_( std::addressof(t) ) {} template <typename Func> void use ( Func f ) const { if ( is_initialized() ) { f( *t_ ); } } private: bool is_initialized() const { return t_ != nullptr; } T* t_; }; template <typename T> inline safe_ref<T> const ref(T& t) { return safe_ref<T>(t); } template <typename T> inline safe_ref<T const> const cref(T const& t) { return safe_ref<T const>(t); } //---------------------------------------------------------------------------- // Usage //---------------------------------------------------------------------------- #include <iostream> #include <string> struct A { void do_something( std::string s ) const { std::cout << "A::do_something with " << s << " and " << i_ << "\n"; } int i_ = 99; }; struct Safe { void set_ref( A& a ) { a_ref_ = ref(a); } void use_ref( std::string s ) const { a_ref_.use( [&s] ( A& a ) { a.do_something(s); }); } safe_ref<A> a_ref_; }; void usage1() { A a; Safe safe; safe.use_ref( "hello" ); //null reference, do nothing safe.set_ref(a); safe.use_ref( "hello world!" ); //safe reference, Ok! } void usage2() { safe_ref<int> si; si.use( [] (int& i ) { std::cout << i << std::endl; }); int temp = 15; safe_ref<int> si2(temp); si2.use( [] (int& i ) { std::cout << i << std::endl; }); si = ref(temp); si.use( [] (int& i ) { std::cout << i << std::endl; }); } //---------------------------------------------------------------------------- It is similar to optional<T>, but in this case the idea is to not allow access to internal data if the pointer is null, only allowing a safe usage There is interest to add something like this to Boost? Any comments or remarks? Thanks and regards, Fernando Pelliccioni.

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[GitHelp] Sandbox library to GitHub
by Edward Diener 27 Dec '12

27 Dec '12

Under Windows following the instructions at https://svn.boost.org/trac/boost/wiki/ExtractSandbox for moving an SVN sandbox library to GitHub I am successful in the first step of cloning SVN sandbox library to a temporary local directory. But when I go to that local directory and try: git push --mirror git@github.com:eldiener/variadic_macro_data.git I receive a PuTTY message of: "Disconnected: No supported authentication methods available (server sent: publickey)" I have no idea how PuTTY gets into this. I am using TortoiseGit and Git for Windows and evidently getting Git to work under Windows is difficult in some way. Anybody have any idea how to straighten this out ?

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[git] What about unmaintained libraries?
by Andrey Semashev 26 Dec '12

26 Dec '12

Hi, I have little experience with git and none with GitHub, so apologies if my questions sound silly. We have a number of unmaintained libraries in Boost. With svn anyone with commit rights can apply fixes and even take over these libs. In the end of the day, I think, this is a good thing - community support is better than no support. Even with maintained libs, it is sometimes simpler to just apply the fix instead of filing a ticket and waiting for the maintainer to get to it. Also, remember the bug fixing weeks we had a while ago - anyone could choose a library and resolve tickets against it. I'm not sure how this will work after transition to git. IIUC, every lib will be extracted into a separate git repository, and presumably only the library maintainer will have the commit rights to that repo. Essentially this means that unmaintained libs will become immutable after the transition. Also, every minor fix will have to go through the library maintainer, however busy he may be. I suppose the problem with unmaintained libs could be solved by forking but what if noone is ready to become the official maintainer but occasionally people commit fixes and improvements to the lib? I believe, at least Boost.DateTime is currently in such situation. Also, forking does not solve the problem for minor fixes to maintained libs. I would really like it if there was some kind of a user group (of all Boost maintainers) that could be used to grant commit rights to the libraries. Whatever the git term is, by "commit" here I mean the ability to publish the changes to the repository on GitHub, so that they are visible to other developers, including monolithic Boost release scripts. Is this possible? If yes, I think all repositories produced as a result of the transition to git should grant commit rights to this group by default, so that the access rights are the same as with svn now.

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[move] uninitialized_move
by Adam Wulkiewicz 26 Dec '12

26 Dec '12

Hi, I recently saw how boost::uninitialized_move is implemented, it doesn't check for exceptions thrown by move ctor and don't delete already constructed objects. Is this intentional? Regards, Adam

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Boost SIMD beta release
by joel falcou 25 Dec '12

25 Dec '12

We're rolling a beta release of Boost.SIMD along with a beta release of NT2. This version comes very late because we were busy with other things but hopefully we'll now do rolling releases frequently. Documentation is quite lacking but code is relatively stable and works. * Release Files can be found here: http://nt2.metascale.org/downloads/ * Additional material about the library can be found here : - Boost.SIMD PACT paper : http://www.lri.fr/~falcou/pub/pact-2012.pdf - Boost.SIMD MeetingC++ slides : http://meetingcpp.com/tl_files/mcpp/slides/12/simd.pdf * We welcome comments, questions and random requests/rants/bug reports as to polish the library before actual submission to the boost review. Such comments can be sent there, on our nt2-dev Google groups or in the nt2 issue tracker. Regards

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automatic SVN mirror down?
by Robin Eckert 24 Dec '12

24 Dec '12

Hello, The latest commit on the live boost SVN mirror (git://github.com/ryppl/boost-svn.git) is 11 days old. Is the automatic mirror jammed right now or is the mirror probably shut down due to the modularization effort? Regards, Robin

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[GitHelp] Help desk ready to assist
by Beman Dawes 24 Dec '12

24 Dec '12

See https://svn.boost.org/trac/boost/wiki/GitHelp for details. --Beman

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[Git] ** Attention All Boost Committers **
by Dave Abrahams 24 Dec '12

24 Dec '12

If you have *ever* checked *anything* (e.g. code or documentation) into the Boost Subversion repository, this message applies to you. Git uses email addresses to identify authors and committers. In order to accurately convert Subversion history to Git, we need to map all (or as many as possible) Subversion user IDs to working email addresses. I have posted a provisional UserID mapping table at https://github.com/boost-lib/boost/wiki/AuthorMapping (with a simple mangling of '@'=>'<>' and '.'=>'~'). If your email address is already in the table, you've been Bcc'd on this message, which may explain the appearance of multiple copies in your mailbox. I request that you make corrections to this table. To edit the table directly, you'll need to be logged into GitHub. Direct correction is by far the preferable approach, but if you don't have---and don't want to acquire---a free GitHub account, you can send edits directly to me. Important notes (these also appear on the page with the table) * You may have several userids (e.g. I appear to have "dave," "abrahams," and "david_abrahams" --- probably left over from the transition from SourceForge CVS to our own SVN). Please look carefully to be sure that you have accounted for all your userids, and please use the same name and email address for each of them. Please *make sure that all non-duplicate userids stay in the table*. For example, all three of my userids are still there. * A given userid may appear several times in the table. If that userid belongs to you, please delete all but one line. If you don't, we will just use the first entry with that userid. * If you have a GitHub account, please make sure the email address you use in the table is associated with that account at https://github.com/settings/emails Thanks for your cooperation. -- Dave Abrahams BoostPro Computing Software Development Training http://www.boostpro.com Clang/LLVM/EDG Compilers C++ Boost

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