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[Boost.Move] [Boost.Container] Compiling with older version of Boost and performance
by Thomas Jordan 07 Jan '12

07 Jan '12

Hi, I am interested in experimenting with v1.48 Boost.Move and Boost.Container. However, I am otherwise constrained to using Boost libraries v1.33.1 with a Sun C++ v5.10 compiler. I couldn't seem any 'Boost library dependencies' listed in the Move/Container documentation, but a quick look through the header files suggests that it is mainly MPL and Type Traits. So... First question: would it be feasible for me to combine the headers for these two libraries with the v1.33.1 libraries and get it to work (albeit maybe with a little customisation), or would it be a big job/non-starter? Second question - I don't see any performance analysis published for Boost.Move. I know that move semantics is about more than improved performance, but am interested in that side of things, especially as the above compiler appears suboptimal in terms of copy elision and RVO. I am wondering for example whether are there any (compiler-specific) factors which could mitigate against the performance benefits of doing a move vs a copy of a vector, using these libraries, for example. Regards, T.

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[Boost.smart_ptr] Thread Safety
by Thomas Jordan 07 Jan '12

07 Jan '12

Hi, Is shared_array completely thread-safe. including destruction/reference counting? http://www.boost.org/doc/libs/1_33_1/libs/smart_ptr/shared_ptr.htm#ThreadSa… // thread A p3 = p2; // reads p2, writes p3 // thread B // p2 goes out of scope: undefined, the destructor is considered a "write access" /bb/source/boost/boost_1_33_1/boost/detail/sp_counted_base_pt.hpp

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On the lack of manpower: (Apache stdcxx)
by Jim Bell 06 Jan '12

06 Jan '12

Though this isn't news, I just came across it and it speaks to our common problem. (And it's of interest to boost users in general.) Note that ARM and Sun are even invested in stdcxx to some extent. From Apache's C++ Standard Library project <http://stdcxx.apache.org/status/2011-02.txt>: Stdcxx continues to be dormant. All but [1] committer have moved on to other projects. The only remaining committer (the VP of the project) is too busy with his day job to make even small changes, or to put out the long-awaited patch release, stdcxx 4.2.2. A number of users and organizations have been using the project and expressed interest in contributing to it. Several submitted patches, others have offered help with the project build and test infrastructure. Unfortunately, since no committer is available to review patches and guide the contributors through the ASF process to enable them to gain commit privileges there seems to be little hope of reviving stdcxx. A possible solution that would allow contributions to resume is to grant commit privileges to the handful of contributors who have already submitted some patches or expressed serious interest in contributing going forward. Another alternative is to move stdcxx to a repository outside of ASF such as SPI (http://www.spi-inc.org/) where interested developers could start committing changes on their own right away, without going through the "training" process. This seems to the preferred solution among at least some of the interested users. Are there any other options? Future plans: Unless the issue with contributions can be resolved in the next quarter I suggest to retire the project.

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[Boost.Lambda] Some new features are suggested: return, iterating yield, & local var
by Huang Huan 06 Jan '12

06 Jan '12

Hi boosters, I'm intrested in Lambda, so I have worked out some new features, and suggest boost lib add them. What can I do next? NEW features: 1. return. why lambda lib do not include this? 2. generate iterator/iteration by lambda using yield return/yield break. 3. local/global var declare and using. 1. return e.g. boost::function<char(int)> f = ( if_ ( _1 >= 0 ) [ return_('a') ], return_('b') ); p.s. return should be supported. 2. iterator/iteration generation by lambda using yield return/yield break const char* p; // we shuld use the local var inside lambda instead of this var p. refer to section 3 iteration<char> it = ( for_(var(p) = _1, *var(p), var(p)++) [ if_(*var(p) != ' ') [ yield_return(*var(p)) ] if_(*var(p) == ';') [ yield_break() ] ] ) ("I love this game; no use"); p.s. The packing iteration interface is very like the yield keyword in C# IEnumeable 3.local/global var declare and using e.g. char a; var_name x, y, z; global_var<int>(y); // put this line inside lambda is ok, just before use it ( ( local_var<int>(x), // local var declare // global_var<int>(y), var(a) = 'a', var<int>(x) = _2, // using local var x ), ( local_var<char>(z), var(a), var<int>(x) = _1, // error! x is not local var here. var<int>(y), // ok for global even if another lambda var<char>(z) = 'b', ) ) p.s. Now, in my work. It's hard to simplify var<T>(x) to var(x). It's a hard template working.

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Re: [boost] [log] Status (was: Is there any interest in a Group of library like to Application System!)
by Andrey Semashev 06 Jan '12

06 Jan '12

On Wednesday, January 04, 2012 09:08:16 Renato Tegon Forti wrote: > Hi Andrey, > > Thanks for your response! What is status of your lib? Do you need any help? The library is moving slowly to v2 release. Right now I'm wrapping up bounded async frontends, I intend to finish them by the weekend. Other things left to be done before the release are: - Port filters and formatters to Phoenix v3. As a part of it, improve error messages in exceptions and make filters and formatters not throw by default. - Introduce "default" sink concept to mitigate problems with trivial and advanced logging coexistence. Trivial logging will no longer initialize the library under the hood. - Implement a common attribute registration mechanism to simplify library extension. This should solve problems with settings file parser not recognizing user-defined attribute types. - Update the documentation. There are many other things to be done but they are not showstoppers for the release. Yes, help would be much appreciated, most notably in the porting to Phoenix v3 part. If anyone is willing to help, please contact me privately or through this list.

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[Graph] Concept check VertexMutablePropertyGraph
by Jens Müller 05 Jan '12

05 Jan '12

Hi, http://www.boost.org/doc/libs/1_48_0/libs/graph/doc/MutablePropertyGraph.ht… (I cannot find docs for VertexMutablePropertyGraph or EdgeMutablePropertyGraph) says that the types boost::graph_traits<G>::vertex_property_type and boost::graph_traits<G>::edge_property_type must exist. However, the concept checks (in boost/graph/graph_concepts.hpp) check for vertex_property_type<G>::type and edge_property_type<G>::type, respectively. Several questions: 1. Should there be separate docs for VertexMutablePropertyGraph and EdgeMutablePropertyGraph? 2. Should there be an actual concept check implementation for MutablePropertyGraph combining the two? 3. Should the concept check look for boost::graph_traits<G>::vertex_property_type instead of ertex_property_type<G>::type? [and the same for edge] 4. For the LEDA adapter, i.e., external adaptation, do I have to specialize vertex_property_type<G> and edge_property_type<G>? Best, Jens

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[graph] VertexListGraph and InputIterator, and LEDA graph
by Jens Müller 05 Jan '12

05 Jan '12

Hi all, I'm currently fixing up leda_graph.hpp so it passes the tests, or indeed, fixing the tests ... A leda::GRAPH<int,int> (=Graph) has to fulfill VertexListGraphConcept. This means that boost::graph_traits<G>::vertex_iterator has to be a MultiPassInputIterator, i.e., also a InputIterator. I cannot read from http://www.sgi.com/tech/stl/InputIterator.html that it must be possible that you can compute the difference between two iterators. But apparently the concept check (which fails) requires a difference type, which must be a signed integer. Is this a bug in the concept check? The vertex_iterator type is defined in leda_graph.hpp using iterator_facade: class vertex_iterator : public iterator_facade<vertex_iterator, leda::node, bidirectional_traversal_tag, const leda::node&, const leda::node*> { public: vertex_iterator(leda::node node = 0, const leda::GRAPH<vtype, etype>* g = 0) : base(node), g(g) {} private: const leda::node& dereference() const { return base; } bool equal(const vertex_iterator& other) const { return base == other.base; } void increment() { base = g->succ_node(base); } void decrement() { base = g->pred_node(base); } leda::node base; const leda::GRAPH<vtype, etype>* g; friend class iterator_core_access; }; Is maybe iterator_facade insufficient? For me, bidirectional_traversal_tag does not indicate that random access is possible ... -- Jens

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[chrono] Possible bug in boost::chrono::process_real_cpu_clock::now() under Windows 32bits
by ivan.lelann＠free.fr 05 Jan '12

05 Jan '12

Hi, As of 1.48 Boost.Chrono contains code below for boost::chrono::process_real_cpu_clock::now() (boost\chrono\detail\inlined\win\process_cpu_clocks.hpp) clock_t c = ::clock(); /* ... */ return time_point( duration(c*(1000000000l/CLOCKS_PER_SEC)) ); duration::rep is int64/nanoseconds, clock_t is long. This is VS2008, Win XP 32bits. I think "c" should be cast to duration::rep before being multiplied. I randomly get negative time_point and this seems to be fixed by replacing "c" with "((duration::rep) (c))" in duration constructor : duration( ((duration::rep) (c)) *(1000000000l/CLOCKS_PER_SEC)) Can someone confirm my view and that the fix is correct ? Regards, Ivan

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Is there any interest in a library for Application System? (Request for comments)
by Renato Tegon Forti 05 Jan '12

05 Jan '12

Some detail (Brainstorm): This library will provide a simple way to create an application that can be: . A Server Application A server application usually starts when system boot, and then remain running as background process, don't matter who is currently logged. In Windows this will a "Windows Service" and in UNIX a "UNIX Daemon", and we can create a "Neutral Application" that is not a daemon and service, but uses "service interface" that will provide methods like an "init", "interrogate", "restart" and so on. Some type of "system global mutex" will be implemented in this flavor, then if user want, he can determine that only one instance of service will run in a system in same time. A web server, data base server and so on area examples. . A Usual Application A usual application is a normal application, that don't need all of features provided by "server application" usually is started by a user and run by a determined period. A command, mail client, MPI master/Slave and so on area examples. . Base Class Both classes will be derivated of environment class that will provide common thinks and proprieties like an "app path", "app name", "app work dir" and so on. For sample: A user that want create a server, extend your class of "server class" and then override methods that want to get needed behavior. // windows service, or daemon class myapp : public boost::application::server{}; // neutral server class myapp : public boost::application::server<neutral>{}; // usual application class myapp : public boost::application::app{}; Note that: 1) Application can be configured using Boost.Program_options 2) I want use Boost.Log to provide log functionality when available. 3) I want create a "service model" then I want use Boost.Extension to provide dynamically late bind extension (Pluf-in System). What Boosters think? This is useful or is fool lib? Boosters think that "this kind of lib" is very specific, and violate: "The library must be generally useful and not restricted to a narrow problem domain." or this kind of system is relevant to boost. Please let me know the correct way to follows! Please make suggestions! What more else? Thanks

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Copyright and authorship notices
by Jens Müller 05 Jan '12

05 Jan '12

Hi all, what is the policy of adding a Copyright notice and entries to the author list when patching existing files? I found http://www.boost.org/development/requirements.html#Ownership, but it is not completely helpful. -- Jens

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