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[1.40.0] Beta planned for this weekend
by Beman Dawes 05 Aug '09

05 Aug '09

I'm planning to put together the 1.40.0 beta this weekend. Please ask permission before updating branches/release. Thanks, --Beman

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Important: Boost server downtime on August 5, 2009
by Doug Gregor 05 Aug '09

05 Aug '09

The Boost mailing lists, web server, and Subversion server will be offline tomorrow (Wednesday, August 5th) from 8:00AM EDT to 9:00AM EDT while we upgrade the mailman software. My apologies for the late notice. - Doug

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Boostcon Keynote (finally!) available.
by Marshall Clow 05 Aug '09

05 Aug '09

at http://boostcon.blip.tv Thank you, everyone, for your patience. More videos from Boostcon will be going up there in the near future. -- Marshall

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Interest in a "Heterogenous Container" system?
by Christian Schladetsch 04 Aug '09

04 Aug '09

Hello, After a discussion on a different thread, I came up with an implementation allowing containers to store and retrieve heterogenous instances, and provide correct deep cloning of those containers. A working motivational example is here http://tinyurl.com/larqyy. I have yet to do a comparison with container<boost::any>. This is just an initial proof-of-concept, and there remains a lot of work to do if it were to be a complete proposal. Before I did that work (especially since I have another proposal in the wings), I wanted to ask if there would be any interest in a completed system? The system is based on a modified ptr_container branch (also in the sandbox - I've contacted Thorsten about this), and and allocator adaptor system to deal with cloning. It allows one to place object pointers into a container using syntax such as: /// a vector of heterogenous objects template <class Alloc = std::allocator<char>, class Base = common_base > struct vector; heterogenous::vector<> v; v.push_back<T0>(); // add a default-constructed object of type T0 v.push_back<T1>(a0,a1,...,an); // add an object of type T1, passig a0..an as ctor arguments T1 &obj = v.ref_at<T1>(1); // get a reference of type T1& to the object at index 1 or throw bad_cast heterogenous::vector<> v2 = v; // copy the container; concrete types are preserved assert(v2.is_type_at<T1>(1)); There are many outstanding issues; it may not fly in the end, it may not work for all container types and semantics, but I would like some early opinion on whether it is even worth my pursuing further. One initial issue that may break any interest is that instances put into the container must be of a type T that derives from heterogenous::base<T>. Regards, Christian.

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Pre-compiled headers, Boost.Thread, and boost/date_time/date_facet.hpp
by Patrick Hartling 04 Aug '09

04 Aug '09

I am using Boost 1.39.0 with Visual C++ 9.0 SP1, and I am having problems with pre-compiled headers that include boost/date_time/date_facet.hpp. I have code organized into several DLLs, and one of the lowest level DLLs in that set has a header file that, as of yesterday, includes headers from Boost.Thread. The highest level DLL provides Python bindings made using Boost.Python for all of the other DLLs. We use pre-compiled headers to get a dramatic speed up of the build of the code that uses Boost.Python, and that was working like a charm until Boost.Thread headers came into the mix. Now, I get this linker error for every object file in the Python bindings DLL: error LNK2001: unresolved external symbol "public: static class std::locale::id boost::date_time::date_facet<class boost::gregorian::date,char,class std::ostreambuf_iterator<char,struct std::char_traits<char> > >::id" (?id@?$date_facet@Vdate@gregorian@boost@@DV?$ostreambuf_iterator@DU?$char_traits@D@std@@@std@@@date_time@boost@@2V0locale@std@@A) The only way that I have found to work around this is to keep anything that might include boost/date_time/date_facet.hpp out of the headers that get pre-compiled. At the moment, that is every Boost.Thread header I am using: boost/thread/{thread,mutex,condition_variable}.hpp. It appears that most of the key Boost.Thread headers end up including boost/thread/xtime.hpp, and that header indirectly includes boost/date_time/date_facet.hpp. Is there any way to work around this? I am not entirely sure what the problem is, but my guess is that it has something to do with an aspect of DLL symbol exporting and the way that the static data member boost::date_time::date_facet<...>::id is defined. I think I ran into something like this once (unrelated to Boost) a couple of years ago, but I am still trying to track down that code. -Patrick -- Patrick L. Hartling Senior Software Engineer, Priority 5 http://www.priority5.com/

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[Range] Boost and N2930?
by Beman Dawes 04 Aug '09

04 Aug '09

N2930, Range-Based For Loop Wording (Without Concepts), provides begin() and end() non-member function templates for standard library types. It also provides general range access non-member templates: // 24.7 range access [iterator.range] template<typename C> auto begin(C& c) -> decltype(c.begin()); template<typename C> auto begin(const C& c) -> decltype(c.begin()); template<typename C> auto end(C& c) -> decltype(c.end()); template<typename C> auto end(const C& c) -> decltype(c.end()); template<typename T, size_t N> T* begin(T (&array)[N]); template<typename T, size_t N> T* end(T (&array)[N]); (Until the official WG21 site gets updated, you can see a copy of n2930 at http://mysite.verizon.net/beman/n2930.html) Should Boost.Range and/or RangeEx be modified and/or extended in light of N2930? Can Boost.Range, RangeEx, or some other Boost component help developers and users who want to take advantage of N2930 in C++03 now, and do so in a way that transitions smoothly to C++0x as language and library available? --Beman

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[function] should it require rtti?
by Emil Dotchevski 03 Aug '09

03 Aug '09

Line 223 in function_base.hpp uses typeid. Can this be avoided? If not, perhaps it can be refactored to use the workaround found in sp_typeinfo.hpp? Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

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Re: [boost] [xpressive] Performance Tuning?
by raindog＠macrohmasheen.com 03 Aug '09

03 Aug '09

I would be very interested in seeing this too as your numbers look extremely good ------Original Message------ From: OvermindDL1 Sender: boost-bounces(a)lists.boost.org To: boost(a)lists.boost.org ReplyTo: boost(a)lists.boost.org Sent: Jul 17, 2009 3:30 PM Subject: Re: [boost] [xpressive] Performance Tuning? On Wed, Jul 15, 2009 at 6:57 AM, OvermindDL1<overminddl1(a)gmail.com> wrote: > /* snip */ So has anyone tried the code I posted to see how it compared? _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost Sent from my Verizon Wireless BlackBerry

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Timing.
by Edward Grace 03 Aug '09

03 Aug '09

Hello All, Rather than replying to previous messages I felt it would be better to start a new and more appropriately titled thread. In the ongoing quest to try and develop a timing system for in-code use and (now) benchmarking as an example application the original code of Joel de Guzman has been extensively modified and uploaded here: http://tinyurl.com/nmhthy The code uses two techniques for calculating the percentage speedup. It is quite likely that the error estimate for the actual run times is very wrong. I strongly suspect that the random error is over- estimated but the systematic error is under-estimated. Note that changing the machine loading can affect the absolute times noticeably. Burst-like behaviour will not matter too much, but sustained loading will. Consequently if you wish to directly compare the ns/char (nanoseconds per character) values between runs or machines care should be taken to make sure the background load is consistent. When looking at the relative times on a given run - particularly with the Wilcoxon test, this is far less important. I look forward to results anyone gets on other machines. Particularly with respect to robustness of the results against background processes, repeatability and or inter-compiler variations. Cheers, -ed $ echo 1000 15 | ./ejg_uint Enter buffer size: Enter nominal precision (%): initializing input strings... Nominal precision of quantum: 15% Timer overhead (t_c) (ticks): 108.321 Jitter (ticks): 8.24459 Approx clock frequency (GHz): 2.1681 Direct point estimates of actual run time. Function T - delta T (best) T + delta (ns/char) (ns/char) (ns/char) qi_parse 47 67 87 strtol 74 1.1e+02 1.4e+02 atoi 79 1.1e+02 1.5e+02 Speedup percentages based on Wilcoxon matched pair confidence intervals. Func. A vs Func. B Minimum Median Maximum (% faster) (% faster) (% faster) qi_parse atoi 69 69.2 69.3 qi_parse strtol 57.8 57.9 58 strtol atoi 7.14 7.16 7.2 qi_parse qi_parse -0.0762 0.00468 0.0343 Speedup percentages based on the point estimates. Func. A vs Func. B Best - err Best Best + err (% faster) (% faster) (% faster) qi_parse atoi 63.1 69.1 75.1 qi_parse strtol 51.8 57.8 63.8 strtol atoi 1.16 7.16 13.2 qi_parse qi_parse -6 0.00222 6 All done! ------------------------------------------------ "No more boom and bust." -- Dr. J. G. Brown, 1997

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Details on boost::serialization
by Per Nordlöw 03 Aug '09

03 Aug '09

I haven't found any documentation on the header bits of the archive formats supported by boost::serialization. These are added as default when I construct binary and text formats. I am especially interested in skipping these headers completely in my application, that is serializing a char should only result in one byte outputted to stream. Does the headers basic_binary_[io]archive.hpp play any roles in this case? I have tried to use them instead by I got some strange error messages so these are commented out here. Thanks in advance, Nordlöw Compileable sample code follows: #include <fstream> // #include <boost/archive/basic_text_iarchive.hpp> // #include <boost/archive/basic_text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <boost/archive/binary_oarchive.hpp> class gps_position { public: gps_position() {}; gps_position(int d, size_t m, float s) : degrees(d), minutes(m), seconds(s) {} private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & degrees & minutes & seconds; } int degrees; size_t minutes; float seconds; }; template<class OA, class IA> static void test(const gps_position & pos, const char * filename) { std::ofstream ofs(filename); // create and open a character archive for output { OA oa(ofs); oa << pos; } gps_position newg; { std::ifstream ifs(filename); // create and open an archive for input IA ia(ifs); ia >> newg; } } int main() { const gps_position p(35, 59, 24.567f); // test<boost::archive::basic_text_oarchive, // boost::archive::basic_text_iarchive>(p, "boost_serialization_basic_text_archive"); test<boost::archive::text_oarchive, boost::archive::text_iarchive>(p, "boost_serialization_text_archive"); test<boost::archive::binary_oarchive, boost::archive::binary_iarchive>(p, "boost_serialization_binary_archive"); return 0; }

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