March 2008 - Boost-users - lists.preview.boost.org

Boost Selected for Google Summer of Code 2008
by Jeff Garland 18 Mar '08

18 Mar '08

For the third year in a row Boost has been selected as a mentoring organization for Google Summer of Code. If you're a student this is a great opportunity to contribute to Boost and make a few dollars over the summer. If you're interested here's some links to get you started. http://code.google.com/opensource/gsoc/2008/faqs.html http://code.google.com/soc/2008/boost/about.html We have a few project ideas at: http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?Google_Summe… but, if you've got your own idea that's fine too. Best to put your ideas out on the development list for writing an application -- that's the best way to be sure the mentors think your project has merit. Here's some important dates to keep in mind: March 24: ~12 noon PDT / 19:00 UTC Student application period opens. March 31: 5:00 PM PDT / 00:00 UTC April 1, 2008 Student application deadline. Full timeline is here: http://code.google.com/opensource/gsoc/2008/faqs.html#0.1_timeline Jeff

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BoostCon 2008 -- Session Announcement
by Jeff Garland 17 Mar '08

17 Mar '08

I'm happy to announce that the preliminary 2008 BoostCon program is on the web site. http://www.boostcon.com/program/sessions I'm quite pleased and excited with the program. We have tutorials and lectures on many core Boost libraries with topics including threading, serialization, networking, C++0x features, high performance generic programming, text processing, and more. We will also have a new 'Library in a Week' workshop to extend Boost.Algorithm. A new feature this year, based on feedback from last year, will be Author's Corner sessions where library authors discuss and answer questions about their libraries. And, finally, Bjarne Stroustrup with the keynote address. We hope to have the final program and schedule completed shortly. Note that while these sessions represent the bulk of the program we have a few more sessions in the works and are still looking for a couple more sessions to fill out the program. So, if you've been thinking of submitting a session please do it as soon as possible. http://www.boostcon.com/program/call-for-sessions Thanks, Jeff

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Threads Don't Take Turns Under Linux (Ubuntu Gutsy Gibbon)
by Hal Vaughan 17 Mar '08

17 Mar '08

I apologize if this gets posted more than once. I found the group on GMane, tried to post, joined the email list, then tried to post several times but still have yet to see it show up. I'm learning C++ and found a tutorial on threads with Boost on Dr. Dobb's site. I've copied the code from this url: http://www.ddj.com/cpp/184401518?pgno=5 It's supposed to fill a buffer with data on one thread and remove data on the other thread. I would expect it to add data and remove at almost the same time but when I run it, it adds 10 items, then removes them, then adds ten again, and so on. It's never adding and removing in an "interleaved" fashion. I've also tried the same with simple counters where both threads count to ten, but it doesn't seem to make a difference. It seems no matter how I set it up, one thread either completes, or runs until it has to stop for a mutex, then the other thread runs. It seems that there is never a case of both threads running at the same time. I've never had trouble doing this in Perl with fork() so I'm not at all sure what could be going wrong. As I said, it's not just the program below, it seems to be any program that uses more than one thread. Am I doing something wrong or is there a setting I need to change? I'm compiling it with "g++ -lboost_thread mthrd.cpp -o mthrd && ./mthrd"; Thanks! Hal ------ #include <boost/thread/thread.hpp> #include <boost/thread/mutex.hpp> #include <boost/thread/condition.hpp> #include <iostream> const int BUF_SIZE = 10; const int ITERS = 100; boost::mutex io_mutex; class buffer { public: typedef boost::mutex::scoped_lock scoped_lock; buffer() : p(0), c(0), full(0) { } void put(int m) { scoped_lock lock(mutex); if (full == BUF_SIZE) { { boost::mutex::scoped_lock lock(io_mutex); std::cout << "Buffer is full. Waiting..." << std::endl; } while (full == BUF_SIZE) cond.wait(lock); } buf[p] = m; p = (p+1) % BUF_SIZE; ++full; cond.notify_one(); } int get() { scoped_lock lk(mutex); if (full == 0) { { boost::mutex::scoped_lock lock(io_mutex); std::cout << "Buffer is empty. Waiting..." << std::endl; } while (full == 0) cond.wait(lk); } int i = buf[c]; c = (c+1) % BUF_SIZE; --full; cond.notify_one(); return i; } private: boost::mutex mutex; boost::condition cond; unsigned int p, c, full; int buf[BUF_SIZE]; }; buffer buf; void writer() { for (int n = 0; n < ITERS; ++n) { { boost::mutex::scoped_lock lock(io_mutex); std::cout << "sending: " << n << std::endl; } buf.put(n); } } void reader() { for (int x = 0; x < ITERS; ++x) { int n = buf.get(); { boost::mutex::scoped_lock lock(io_mutex); std::cout << "received: " << n << std::endl; } } } int main(int argc, char* argv[]) { boost::thread thrd1(&reader); boost::thread thrd2(&writer); thrd1.join(); thrd2.join(); return 0; }

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[tokenizer] mutable string iterator
by Christian Henning 17 Mar '08

17 Mar '08

Hi there, I would like to use the tokenizer to iterate through a string of words and reverse them. Something like this: string str( " Hello World" ); tokenizer<> tok(str); for(tokenizer<>::iterator beg=tok.begin(); beg!=tok.end();++beg) { reverse( (*beg).begin(), (*beg).end() ); } Why can't I get a mutable string iterator? Thanks, Christian

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[mpl] apply is_base_and_derived to class template and deduce types
by Ares Lagae 17 Mar '08

17 Mar '08

I have a base class template "template <typename T1, typename T2> struct base {};" and a derived class "derived" that publicly derives from several instantiations from the base class template. Given a type "T1", is it possible to decide if the class "derived" is derived from a base "base<T1,X>" and deduce the unknown type "X"? Best regards, -- Ares Lagae Computer Graphics Research Group, Katholieke Universiteit Leuven http://www.cs.kuleuven.be/~ares/

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Features list for v1.34
by Balasubramanyam, Shivakumar 17 Mar '08

17 Mar '08

Hi, Could someone point me to a link that provides features added or major bugs fixed for a major boost release. Currently we are using 1.32 and I would like to know if we need to upgrade to 1.34 releases. I tried in the boost.org but could not find a link. Thanks, Shiva

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GraphProperty with adjacency_list cause a VC++ internal compiler error.
by Schick, Thorben (ITUC; ADITG/DFG) 17 Mar '08

17 Mar '08

Does anybody know if this will be fixed with the upcoming boost release/the new VS 9.0? Or is there some kind of workaround to solve this problem? I've already post this question, but i'm not sure if this worked...so i try again... Regards Thorben

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[GIL] Where I can find docs
by Igor Mikushkin 17 Mar '08

17 Mar '08

Hello. Please tell me where I can find GIL documentation. Thanks Igor Mikushkin

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Question on create_thread()
by Alexander Dong Back Kim 17 Mar '08

17 Mar '08

Hi all, I'm a new user of BOOST library. I'm creating a class that requires to do some multi threading stuff. The class I'm creating has a method... void Calculator::Calc(int value) { ... } In order to run multiple Calc() in different threads, I created another method FindResult() the implementation was... void Calculator::FindResult(int numbers) { thread_group group; boost::function<void (Calculator *, int value)> boostFunction; boostFunction = &Calculator::Calc; for(int i=0; i<3; i++) { boost::thread * th = group.create_thread(&boostFunction); } } However, it seems it doesn't work at all... Is there any idea?? Cheers, -- Alexander Dong Back Kim Australia +61 433 469 100 / Korea +82 10 6357 8840

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Update for Australian DST changes.
by Brendon Oliver 16 Mar '08

16 Mar '08

Hi all, I've had to update my date_time_zonespec.csv file for this year's DST changes for Australia, copy of the file attached for anyone else needing it [all care, no responsibility, etc. etc. - the usual disclaimer :-) ] I generated this file based on the system zoneinfo database contained in FreeBSD 7.0, but that still shows last year's DST changes for Hobart - the attached file was manually updated to correct that. cheers, - Brendon. -- BOFH excuse #96: Vendor no longer supports the product 10:45:49 up 23 days, 20:28, 6 users, load average: 0.12, 0.18, 0.14

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