November 2008 - Boost - lists.boost.org

Download links on Boost homepage
by Phil Endecott 10 Nov '08

10 Nov '08

Dear All, It seems to take more clicks than necessary to get from the Boost home page to the 1.37.0 download. On the Boost home page there is a heading "News" and under it a link "Version 1.37.0" to http://www.boost.org/users/news/version_1_37_0. To the right of this there's a heading "Downloads" and under it a link "Version 1.37.0" to http://www.boost.org/users/download/version_1_37_0. However, as far as I can see the latter page is identical to the former page; both are news pages listing new and updated libraries etc. The latter page should really have got me closer to being able to download the release, shouldn't it? Phil.

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[thread] shouldn't at_thread_exit work on the main thread?
by vicente.botet 10 Nov '08

10 Nov '08

Hi, in the following example mycallable1 is not called at exit of the main thread. Shouldn't at_thread_exit work on the main thread? What is wrong? Best, Vicente #include <boost/thread.hpp> #include <iostream> struct mycallable1 { void operator()() const { std::cout << "mycallable1" << std::endl; }; }; struct mycallable2 { void operator()() const { std::cout << "mycallable2" << std::endl; }; }; void my_thread() { std::cout << "my_thread" << std::endl; mycallable1 x; boost::this_thread::at_thread_exit(x); } int main() { mycallable2 x; boost::this_thread::at_thread_exit(x); boost::thread th(my_thread); th.join(); return 0; } Output: my_thread mycallable1 EXIT STATUS: 0

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Interest in an Active Object CRTP "decorator"?
by Dean Michael Berris 10 Nov '08

10 Nov '08

Hi Guys, I've recently been working a lot with Active Object implementations. Basically it's an instance of a class that has asynchronous operations scheduled to be executed in its own thread of execution. I'm posting (in-line) a very simple implementation of a CRTP "active object enabler". Any interest in something like this to be included in Boost? --->8-- [NOTE: untested, licensed under the Boost Software License, Copyright 2008 Dean Michael Berris] template <class Derived> struct active { private: shared_ptr<io_service> queue; shared_ptr<io_service::work> sentinel; shared_ptr<thread> lifetime_thread; protected: active() : queue(new io_service()), sentinel(new io_service::work(*queue)), lifetime_thread(new thread(bind(&io_service::run, queue))) { static_cast<Derived*>->init(); }; ~active() { sentinel.reset(); lifetime_thread->join(); static_cast<Derived*>->destroy(); }; void post(function<void()> f) { queue->post(f); }; }; --->8-- Example usage would be something like this: --->8-- struct logger : active<logger> { void init() { }; // required void destroy() { }; // required void operator() (string const & message) { active<logger>::post(bind(&logger::write, this, string(message))); } void write(string message) { cout << message << endl; } }; // ... vector<string> messages; logger log_; for_each(messages.begin(), messages.end(), ref(log_)); --->8-- Hope this helps! -- Dean Michael C. Berris Software Engineer, Friendster, Inc.

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[cryptography] concept
by Kasra Nassiri(Math & ComSci) 10 Nov '08

10 Nov '08

Hi all, I mentioned not a while ago that I am planning to write a boost cryptographic library. I am getting there. We have template classes that implement a certain interface (not virtual functions). These classes are: secure_allocator: An allocator which removes the buffers allocated when they are destructed by overwriting them. block_cipher: Any class that could set a key and encrypt/decrypt a constant size of message. (I have included AES, Serpent, Twofish and MARS, however, we could always add more algorithms) stream_cipher: By definition stream_cipher is a cipher that could process messages of any length. hash_function: Is a class that could compute a cryptographically secure hash signature for an arbitrarily long messages. (I have added whirlpool and will be adding more). wipe_algorithm: An algorithm that provides the patterns of wipe for a given pass and fills a given buffer with patterns (It needs to have a prng template to be used on random patterns). By using a mode of operation we could turn the concept of block_cipher into a stream_cipher. For example cryptolib::ctr<cryptolib::aes> is a stream_cipher concept. I have implemented ictr, ctr and will be implementing XTS, LRW soon. classes: cryptolib::entropy_poll<cryptolib::hash_function>: A class that polls random data and mixes the data using a hash function. cryptolib::entropy_thread<cryptolib::entropy_poll>: Calling the polling function of the entropy_poll at "random" but regulated intervals using boost::thread library. cryptolib::crypto_istream<cryptolib::stream_cipher>: cryptolib::crypto_ostream<cryptolib::stream_cipher>: cryptolib::crypto_oistream<cryptolib::stream_cipher>: classes that behave similar to 'std' iostream ,however, they seamlessly encrypt/decrypt the data as they operate. cryptolib::wipe_fstream<cryptolib::wipe_algorithm>: Wipes the file using the patterns by the template wipe algorithm. This class would determine the cluster size and wipe the entire cluster occupied by the file (this is platform specific, so we need to implement the algorithm for different platforms). finally we have the cryptolib::crypto_fstream that could be given a direction (i.e. encryption or decryption) and will operate seamlessly on the data. What do you think? Anything that I am missing on? Best regards Kasra __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: [boost] [serialization] basic_text_iprimitive destructor throws
by John Salmon 10 Nov '08

10 Nov '08

Here's a two-line patch (not counting the comment). This patch simply ignores any ios_base::failure excpetions from is.sync(). There are certainly other possibilities, but I don't see any good reason to prefer, e.g., checking the result of std::uncaught_exception() first or to broaden the class of caught exceptions. John P.S. I've changed the subject to adhere to conventions. salmonj(a)drdblogin6.en.desres$ diff -u boost/archive/impl/basic_text_iprimitive.ipp.orig boost/archive/impl/basic_text_iprimitive.ipp --- boost/archive/impl/basic_text_iprimitive.ipp.orig 2008-11-09 16:32:30.003405292 -0500 +++ boost/archive/impl/basic_text_iprimitive.ipp 2008-11-09 16:38:51.755281718 -0500 @@ -147,7 +147,17 @@ template<class IStream> BOOST_ARCHIVE_OR_WARCHIVE_DECL(BOOST_PP_EMPTY()) basic_text_iprimitive<IStream>::~basic_text_iprimitive(){ - is.sync(); + try{ + is.sync(); + }catch(std::ios_base::failure& e){ + // is.sync might throw ios_base::failure if an error + // occurs and 'is' has the badbit exception + // mask set. Should this exception be allowed to "leak out" + // of this destructor: + // a) never? + // b) only if std::uncaught_exception() is false? + // c) under some other set of circumstances? + } } } // namespace archive salmonj(a)drdblogin6.en.desres$ On Tue, Nov 4, 2008 at 4:17 PM, John Salmon <john(a)thesalmons.org> wrote: > I tried turning on exceptions on the input stream that I use for a > text_iarchive, hoping to catch user-level errors such as an attempt to > treat a non-archive file as an archive. It seems that when exceptions > are enabled on the underlying stream, the basic_text_iprimitive > destructor throws a second(?) basic_ios::failure exception, during > stack unwinding, which lands me unhappily in the terminate handler. > > Can the basic_text_iprimitive destructor be protected against > accidentally throwing? > > Here's an demonstration. This is on a Linux system with gcc/4.1.2. > > John Salmon > > salmonj(a)drdblogin6.en.desres$ cat ser.cpp > #include <boost/archive/text_iarchive.hpp> > #include <boost/serialization/serialization.hpp> > #include <stdexcept> > > #include <fstream> > > struct Foo{ > int i, j; > private: > friend class boost::serialization::access; > template <class Archive> > void serialize(Archive & ar, const unsigned int version) > { > ar & i & j; > } > }; > > int main(){ > Foo foo; > std::ifstream ifs("/dev/null"); > ifs.exceptions(std::istream::failbit | std::istream::badbit); > > try{ > boost::archive::text_iarchive tia(ifs); > tia >> foo; > }catch(std::ios_base::failure &e){ > std::cerr << "Caught std::ios_base::failure. What: " << > e.what() << "\n"; > }catch(std::exception &e){ > std::cerr << "Caught exception. What: " << e.what() << "\n"; > } > > return 0; > } > > salmonj(a)drdblogin6.en.desres$ xmk > g++ -I/proj/desres/root/Linux/x86_64/boost/1_37_0-13/Release/include > -g -L/proj/desres/root/Linux/x86_64/boost/1_37_0-13/Release/lib > -Wl,-rpath,/proj/desres/root/Linux/x86_64/boost/1_37_0-13/Release/lib > ser.cpp -lboost_serialization -o ser > salmonj(a)drdblogin6.en.desres$ ser > terminate called after throwing an instance of 'std::ios_base::failure' > what(): basic_ios::clear > Aborted (core dumped) > salmonj(a)drdblogin6.en.desres$ gdb -c > drdblogin6.en.desres.deshaw.com-6718.core ser > GNU gdb 6.8 > Copyright (C) 2008 Free Software Foundation, Inc. > License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> > This is free software: you are free to change and redistribute it. > There is NO WARRANTY, to the extent permitted by law. Type "show copying" > and "show warranty" for details. > This GDB was configured as "x86_64-unknown-linux-gnu"... > Reading symbols from > /proj/desrad-c/root/Linux/x86_64/boost/1_37_0-13/Release/lib/libboost_serialization.so...done. > Loaded symbols for > /proj/desres/root/Linux/x86_64/boost/1_37_0-13/Release/lib/libboost_serialization.so > Reading symbols from > /proj/desrad-c/root/Linux/x86_64/gcc/4.1.2-10/lib64/libstdc++.so.6...done. > Loaded symbols for > /proj/desres/root/Linux/x86_64/gcc/4.1.2-10/lib64/libstdc++.so.6 > Reading symbols from /lib64/tls/libm.so.6...done. > Loaded symbols for /lib64/tls/libm.so.6 > Reading symbols from > /proj/desrad-c/root/Linux/x86_64/gcc/4.1.2-10/lib64/libgcc_s.so.1...done. > Loaded symbols for > /proj/desres/root/Linux/x86_64/gcc/4.1.2-10/lib64/libgcc_s.so.1 > Reading symbols from /lib64/tls/libc.so.6...done. > Loaded symbols for /lib64/tls/libc.so.6 > Reading symbols from /lib64/ld-linux-x86-64.so.2...done. > Loaded symbols for /lib64/ld-linux-x86-64.so.2 > Core was generated by `ser'. > Program terminated with signal 6, Aborted. > [New process 6718] > #0 0x0000003f72a2e25d in raise () from /lib64/tls/libc.so.6 > (gdb) where > #0 0x0000003f72a2e25d in raise () from /lib64/tls/libc.so.6 > #1 0x0000003f72a2fa5e in abort () from /lib64/tls/libc.so.6 > #2 0x00002b5ab82f5f84 in __gnu_cxx::__verbose_terminate_handler () > at /state/partition1/tmp/tmpXcQw4O/gcc-4.1.2-10/gcc-4.1.2/libstdc++-v3/libsupc++/vterminate.cc:97 > #3 0x00002b5ab82f4106 in __cxxabiv1::__terminate (handler=0x1a3e) > at /state/partition1/tmp/tmpXcQw4O/gcc-4.1.2-10/gcc-4.1.2/libstdc++-v3/libsupc++/eh_terminate.cc:43 > #4 0x00002b5ab82f350b in __cxa_call_terminate (ue_header=0x50b730) > at /state/partition1/tmp/tmpXcQw4O/gcc-4.1.2-10/gcc-4.1.2/libstdc++-v3/libsupc++/eh_call.cc:60 > #5 0x00002b5ab82f3fa7 in __gxx_personality_v0 ( > version=<value optimized out>, actions=6, > exception_class=<value optimized out>, ue_header=0x50b730, > context=0x7ffff29e5610) > at /state/partition1/tmp/tmpXcQw4O/gcc-4.1.2-10/gcc-4.1.2/libstdc++-v3/libsupc++/eh_personality.cc:637 > #6 0x00002b5ab846a068 in _Unwind_RaiseException_Phase2 (exc=0x50b730, > context=0x7ffff29e5610) > at /state/partition1/tmp/tmpXcQw4O/gcc-4.1.2-10/gcc-4.1.2/gcc/unwind.inc:66 > #7 0x00002b5ab846a2db in _Unwind_Resume (exc=0x50b730) > at /state/partition1/tmp/tmpXcQw4O/gcc-4.1.2-10/gcc-4.1.2/gcc/unwind.inc:234 > #8 0x00002b5ab80fd790 in > boost::archive::basic_text_iprimitive<std::istream>::~basic_text_iprimitive > () > from /proj/desres/root/Linux/x86_64/boost/1_37_0-13/Release/lib/libboost_serialization.so > #9 0x00002b5ab8109e0c in > boost::archive::text_iarchive_impl<boost::archive::text_iarchive>::text_iarchive_impl > () > from /proj/desres/root/Linux/x86_64/boost/1_37_0-13/Release/lib/libboost_serialization.so > #10 0x00000000004045ab in text_iarchive (this=0x7ffff29e5ae0, > is=@0x7ffff29e58d0, flags=0) > at /proj/desres/root/Linux/x86_64/boost/1_37_0-13/Release/include/boost/archive/text_iarchive.hpp:110 > #11 0x0000000000402c84 in main () at ser.cpp:24 > (gdb) quit > salmonj(a)drdblogin6.en.desres$ >

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[serialization] "Wrapper Type?"
by David Abrahams 09 Nov '08

09 Nov '08

Hi, The documentation uses this term AFAICT without definition anywhere. How am I supposed to know that what I've defined is a "wrapper type" and is_wrapper should be specialized? TIA, -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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[thread] no documented thread move support functions on reference documentation
by vicente.botet 08 Nov '08

08 Nov '08

Hi, the following move support functions are not docummented on the reference documentation. #ifdef BOOST_HAS_RVALUE_REFS template <class F> thread(F&& f); thread(thread&& other); thread& operator=(thread&& other); thread&& move(); #else #ifdef BOOST_NO_SFINAE #else template <class F> explicit thread(F f,typename disable_if<boost::is_convertible<F&,detail::thread_move_t<F> >, dummy* >::type=0) #endif template <class F> explicit thread(detail::thread_move_t<F> f); thread(detail::thread_move_t<thread> x); thread& operator=(detail::thread_move_t<thread> x); operator detail::thread_move_t<thread>(); detail::thread_move_t<thread> move(); #endif Even if the semantics of these functions could be induced for completud it will be good to add them to the reference documentation. The ticket is Ticket #2486 Thanks, Vicente

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[flyweight] post-review version available
by JOAQUIN M. LOPEZ MUÑOZ 08 Nov '08

08 Nov '08

Hello, I'm happy to announce the availability of the post-review version of Boost.Flyweight: *Online docs:* http://tinyurl.com/2sstyr http://svn.boost.org/svn/boost/sandbox/flyweight/libs/flyweight/index.html *Download as .zip:* http://tinyurl.com/hrdm6 http://www.boost-consulting.com/vault/index.php?&direction=0&order=&directo… *Check out from SVN:* https://svn.boost.org/svn/boost/sandbox/flyweight *Tested with:* MSVC++ 8.0 and GCC 3.4.4. Compilation reports most welcome. Older compilers like MSVC++ 6.5 are no longer supported. *What's new:* I've tried to address most of the suggestions and comments raised during the review. The two most important changes are: 1. Alberto Barbati's insightful review has led to the introduction of so-called key-value flyweights (http://tinyurl.com/5mnwjp ). This type of flyweights is meant for the situations where constructing the underlying type is expensive and must be avoided except if absolutely necessary. I think the design is robust enough and covers the variants (inner/outer key) that arose during the discussion with Alberto. 2. A comprehensive performance section is provided (http://tinyurl.com/5ap5kt ). *What's pending* 1. Some of the suggestions given at the review, like reducing intermodule_holder to static_holder when permissible (Vicente Botet) or studying read/write locking policies are still pending or have been postponed to later releases of the library. I felt the current state is sufficiently robust for publication. 2. Serialization support is currently broken, pending the resolution of a proposed feature to add to Boost.Serialization (run-time archive helpers). I'd be very grateful if you can take a look at the post- review version of Boost.Flyweight (specially if you were a reviewer), test it and comment on it, with emphasis on the new features like key-value flyweights. If people are happy with this revision my target release for inclusion will be Boost 1.38. Thank you, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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[serialization] Query archive consumed?
by David Abrahams 07 Nov '08

07 Nov '08

Hi, I'd like to verify that there's no data left in a particular archive once I've deserialized my stuff out of it. Is there an appropriate check I can use? Thanks, -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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[threadpool] v15 - final version (?)
by Oliver Kowalke 07 Nov '08

07 Nov '08

Hello, version 15 of threadpool is out - I hope it is the final version. The code doesn't use fibers - fork/join is implemented via recursive execution of tasks (in task::get()). Only tasks in the local worker-queue will be recursivly executed. The work-thread will block in task::get() if the local worker-queue is empty (happens if at least one other worker-thread has stolen a task from the local queue). regards, Oliver -- GMX Download-Spiele: Preizsturz! Alle Puzzle-Spiele Deluxe über 60% billiger. http://games.entertainment.gmx.net/de/entertainment/games/download/puzzle/i…

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