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[proto] Manipulating _data
by David A. Greene 01 Feb '10

01 Feb '10

So I've had fun tinkering with my lambda-like language. I moved on to try to introduce scoping, but I'm having some trouble. I've attached a simplified example. Compiling as-is, the test outputs what I would expect. It seems like the LookupSymbol transform works brilliantly, so symbol lookup is a go. However, convincing the grammar to match an expression that invokes the AddScope transform seems more difficult. Commenting the #if clause results in an error about converting a Wrapper<...> to a shared_ptr<Base> which I can only guess means the grammar is not matching the proto expression. I've tried all sorts of different things. I don't think the UnaryPassThrough transform should be neccessary, but maybe it does't hurt either. With or without it, the error is the same. What am I missing here? Thanks! -Dave

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boost::weak_ptr usage in multithreaded environments
by Virgil Palanciuc 01 Feb '10

01 Feb '10

Hello all, [long story short: I'd like to know whether a weak_ptr.lock() counts as a "shared pointer read" or as a "shared pointer write" ] I'm using boost shared pointers in an multi-threaded app. Basically, my app maintains a "forest" of "context trees" - i.e. I have a map from a "file name" to a "global context" that organizes the information for that file. The "global context" in the map is basically the root node of a tree of "local contexts" in that file. The tree is kept with boost:shared_ptr<> on the way down (father-son relations) and boost::weak_ptr<> on the way up (son->father pointers). I have added proper synchronization to the data structure... I think. I use reader/writer locks (only one writer allowed, but arbitrary number of readers) and I'm still getting sporadic crashes, especially when constructing a "global context" (root node) shared_ptr<> from a weak_ptr<> - using lock(). I am assuming in my app. that weak_ptr<>.lock() only requires a "read lock", not a "write lock".. is this true? I've checked out the page at http://www.boost.org/doc/libs/1_41_0/libs/smart_ptr/shared_ptr.htm#ThreadSa…, but there's nothing about weak_ptr there... Thanks, Virgil.

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BoostCon 2010 preliminary program
by Hartmut Kaiser 01 Feb '10

01 Feb '10

Hey all, please find below a list of accepted submissions to BoostCon 2010. A tentative, fully scheduled program will be available soon. The keynote will be held by Maurice Herlihy. Maurice Herlihy is a computer scientist active in the field of multiprocessor synchronization. Herlihy has contributed to the design of concurrent algorithms, and in particular to the exposition and quantification of the properties and uses of hardware synchronization operations. He is currently (2009) a professor of computer science at Brown University and one of the leading visionaries in the field of transactional memory. Following up on this keynote we will have a full day sessions and panel discussion where we plan for 4 different groups to talk about their work on transactional memory (Mark Moir (Sun), Tatiana Shpeisman (Intel), Michael Wong (IBM), Vicente Botet (TBoost.STM)) In addition we have a high quality, distinctive, fully packed, and very diverse list of accepted talks: João P. R. Abecasis: Cross-platform development with Qt and Boost Ruediger Berlich: Distributed parametric optimization with the Geneva library Dean Michael Berris: Techniques in Flexible Header-Only C++ Network Library Implementations Michael Caisse: Using Spirit 2.1: Qi and Karma An Asio Based Flash XML Server Marshall Clow: A (proposed) MIME library for Boost Tony Van Eerd: The Basics of Lock-free Programming Joel Falcou and Jean-Thierry Lapresté: The Numerical Template Toolbox: BOOST'ed Generic Array Library for High Performance Computing Joachim Faulhaber: Boost.Alabaster (proposed): A Law Based Tester Barend Gehrels, Bruno Lalande and Mateusz Loskot: Generic Programming for Geometry Justin Gottschlich: TBoost.STM's Engine: An Efficient Software Transactional Memory Using Commit-Time Invalidatio Douglas Gregor: Clang: An Open-Source C++ Compiler Library C++ Tool-Builders Workshop Christophe Henry: Tutorial: The Meta State Machine Library V2 Ken Joyner: Revisiting Guidelines to Using Exceptions in C++ Hartmut Kaiser and Joel de Guzman: RAD Spirit Spirit History and Evolution Zachary Laine and Matt Calabrese: Instantiations Must Go! Stephan Lavavej: Data Structure Visualizers in Visual Studio 2010 Nevin Liber: Type Erasure Eric Niebler: Practical DSEL Design with Proto Roshan Naik: Logic Paradigm for C++ Stjepan Rajko: Patterns Library: a generic library for modeling, recognition, and synthesis of sequential patterns Gennadiy Rozental: Production use of Boost.Test David Sankel: Functional Programming in C++ Jeremy Siek: Generic Programming and the Boost Graph Library Robert Ramey: Is Boost Broken? Michael Wong: C++0x Update C++0x Concurrency We believe this program is reason enough to come to BoostCon this year (Aspen, CO, USA, May 10-14th)! For registration, accommodation, and more information please visit the conference website at http://www.boostcon.com. Please note the reduced early registration fee! Regards Hartmut Program Chair BoostCon 2010 --------------- Meet me at BoostCon www.boostcon.com

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boost::random: get same number sequences 32/64 bit?
by Sebastian Mach 01 Feb '10

01 Feb '10

Hello list, today I found out that boost::random, at least the combination boost::mt19937 rng(<seed>); typedef boost::uniform_int<int> dist_t; dist_t dist (<min>, <max>); boost::variate_generator< boost::mt19937&, dist_t > rand_ (rng, dist); will give me different results depending on whether I use "g++ (Debian 4.3.2-1.1) 4.3.2" (with sizeof(long)=8) or "g++.exe (TDM-2 mingw32) 4.4.1" (with sizeof(long)=4). This testcase: ++ #include <boost/random.hpp> boost::mt19937 rng(1); typedef boost::uniform_int<int> dist_t; dist_t dist (0, 16); boost::variate_generator< boost::mt19937&, dist_t > rand_ (rng, dist); int main () { for (int i=0; i<6; ++i) { std::cout << rand_() << std::endl; } } -- will print 16 8 1 6 0 12 with the 64bit variant variant, but 7 16 12 15 0 2 with the 32bit variant. Is there a (preferably portable) way to ensure that they will be the same on all 32bit+ machines? Otherwise this would be a real stopper to use boost::random for me, and I'd have to go back to libcoyotl's Mersenne Twister, which gives consistent results, upon which I really depend. Sincerely Sebastian Mach phresnel(a)gmail.com

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PP: how to use automatic recursion
by Hicham Mouline 01 Feb '10

01 Feb '10

Hello, I am trying to generate many types from 1 struct (for full background, please see thread "generate structs with all combinations of members from a given struct"), with the help of Boost.PP #include <boost/preprocessor/control/if.hpp> #include <boost/preprocessor/seq/size.hpp> #include <boost/preprocessor/seq/seq.hpp> #include <boost/preprocessor/seq/elem.hpp> #include <boost/preprocessor/arithmetic/sub.hpp> #include <boost/preprocessor/seq/pop_front.hpp> #include <boost/preprocessor/seq/push_back.hpp> #define STRUCTMEMBERS ((double,m1))((double,m2))((double,m3))((double,m4))((double,m5)) #define SEQ_LAST_ELEM(seq) \ BOOST_PP_SEQ_ELEM( BOOST_PP_SUB(BOOST_PP_SEQ_SIZE(seq), 1), seq) #define UPDATE_MAIN_SEQ(mainseq, globalseq)\ BOOST_PP_IF( BOOST_PP_SEQ_SIZE(mainseq),\ BOOST_PP_SEQ_PUSH_BACK(\ mainseq,\ ((SEQ_LAST_ELEM(mainseq))(BOOST_PP_SEQ_HEAD(globalseq)))\ ),\ ((BOOST_PP_SEQ_HEAD(globalseq)))\ ) #define COMBINATIONS(seq, combseq)\ BOOST_PP_IF( BOOST_PP_SEQ_SIZE(seq),\ COMBINATIONS( UPDATE_MAIN_SEQ(combseq,seq), BOOST_PP_SEQ_POP_FRONT(seq) ), \ combseq\ ) #define COMBOS COMBINATIONS(STRUCTMEMBERS, BOOST_PP_SEQ_NIL) COMBOS Reading PP docs, I just realized that the preprocessor disallows recursion ( the COMBINATIONS macro calls itself in my case), but I didn't understand the reentrancy topic page. How can I change the above code to make the recursive COMBINATIONS possible? regards,

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[range_ex]"Practical" Status of boost::range, boost::range_ex, and associated algorithms
by Jesse Perla 01 Feb '10

01 Feb '10

Hi there, I am excited to start using ranges in user code with standard algorithms (mostly copy, transform, binary_searches). Is it safe for me to start using code with range/range_ex? Since the http://www.boostpro.com/vault/index.php?directory=Algorithms version hasn't been updated for a while, I was worried that there could be interface changes. I am perfectly willing to use a subset of algorithms that are expected to remain stable -Jesse

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mix usage of boost.thread and pthread?
by Hua Su 01 Feb '10

01 Feb '10

Hi all, Is it OK to use both pthread and boost.thread in the same program under linux? E.g., there are two cases: 1. use pthread api to create/join/detach/cancel threads but use boost.thread's mutex/condition_variable etc. to do thread synchronization, and this_thread/sleep/get_id/thread_local_storage etc.. 2. use boost.thread api to create/join/detach/interrupt thread but use pthread api to do thread synchronization. I know boost.thread is a pthread api wrapper under linux, but I'm afraid of that the two cases above aren't safe if boost.thread uses some tricks I don't understand. Would you kindly give any hints? Thanks! Hua

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[property_tree]problem with equal_range
by Ken Murphy 01 Feb '10

01 Feb '10

Hello all, I am getting an error while trying to compile the following program: #include "boost/property_tree/ptree.hpp" int main(int argc, char* argv[]) { boost::property_tree::ptree t; t.equal_range("KEY"); return 0; } Compiler output: 1>c:\hibbettlinux\src\boost-1.41.0\boost\property_tree\detail\ptree_impl 1>emen tation.hpp(448) : error C2039: 'base' : is not a member of 'boost::multi_index::detail::bidir_node_iterator<Node>' 1> with 1> [ 1> Node=boost::multi_index::detail::ordered_index_node<boost::multi_index::deta il::index_node_base<std::pair<const std::string,boost::property_tree::basic_ptree<std::string,std::string>>,std: :allocator<std::pair<const std::string,boost::property_tree::basic_ptree<std::string,std::string>>>>> 1> ] 1> c:\hibbettlinux\src\boost-1.41.0\boost\property_tree\detail\ptree_implementa tion.hpp(444) : while compiling class template member function 'std::pair<_Ty1,_Ty2> boost::property_tree::basic_ptree<Key,Data>::equal_range(const std::basic_string<_Elem,_Traits,_Ax> &)' 1> with 1> [ 1> _Ty1=boost::property_tree::basic_ptree<std::string,std::string>::assoc_itera tor, 1> _Ty2=boost::property_tree::basic_ptree<std::string,std::string>::assoc_itera tor, 1> Key=std::string, 1> Data=std::string, 1> _Elem=char, 1> _Traits=std::char_traits<char>, 1> _Ax=std::allocator<char> 1> ] 1> c:\hibbettlinux\src\platform\vc80\test\test.cpp(9) : see 1> reference to class template instantiation 'boost::property_tree::basic_ptree<Key,Data>' being compiled 1> with 1> [ 1> Key=std::string, 1> Data=std::string 1> ] 1>c:\hibbettlinux\src\boost-1.41.0\boost\property_tree\detail\ptree_impl 1>emen tation.hpp(449) : error C2039: 'base' : is not a member of 'boost::multi_index::detail::bidir_node_iterator<Node>' 1> with 1> [ 1> Node=boost::multi_index::detail::ordered_index_node<boost::multi_index::deta il::index_node_base<std::pair<const std::string,boost::property_tree::basic_ptree<std::string,std::string>>,std: :allocator<std::pair<const std::string,boost::property_tree::basic_ptree<std::string,std::string>>>>> 1> ] I am using boost 1.41 with VC 7.1 Any help is appreciated!!!!!! Ken Murphy

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Re: [Boost-users] [boost.asio] Flush serial port buffers?
by Pascal Kesseli 01 Feb '10

01 Feb '10

No ideas on this one? > Hi everyone > > My program currently writes some characters to a > device connected over the serial interface and > subsequently changes the baud rate, followed by > sending some more characters. > > The problem is that the first transfer does not > seem to complete before the baud rate switch and > thus is sent with the new baud rate, which is not > supposed to happen. What I am looking for is > something like a flush() before changing the baud > rate. Using: > > boost::asio::write(*port, buffer(buf, size), transfer_all()); > > does not seem to work. Any suggestions? > > Thanks and best regards > Pascal

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Mingw: build, install, .LIB files and boost-config?
by John Pye 01 Feb '10

01 Feb '10

Hi all While I'm aware that MinGW is not one of the 'primary' platforms for MinGW, I wanted to ask a few questions to help me in the task of building a binary copy of Boost for this platform that's as good as it can be. Firstly, what would be the correct build commands to build Boost for MinGW such that I end up with both shared libraries and static libraries? What I've worked out so far is shown here: http://ascendwiki.cheme.cmu.edu/Binary_installer_for_Boost_on_MinGW Secondly, to install Boost at an arbitrary path under MinGW, what is the correct BJAM command? On MinGW, I'm not running ./configure, so the suggestions from the Unix build documentation don't make sense. By default under MinGW, if I run "bjam install", my files end up in c:\Boost but I'd like too have another target directory, so that it's possible to build even without write privileges to that folder. Is there such a thing as "bjam --install-prefix=c:/MinGW install"? Is there a way to strip out all the redundant folder levels like "release" and "gcc-mingw-3.4.5" etc? Third, using BJAM on MinGW results in .LIB files being generated. These .LIB files are NOT correctly names for use with MinGW. As far as I can tell, I have to rename them as .A files, or else do something else with them so that they'll correctly be detected by the the GCC "-l" linker flag. Finally, there was a bit of discussion on the mailing list about a year ago about providing a "boost-config" script. With the ever-changing naming conventions for Boost libs, and the possible presence of static libraries, shared libraries, -mt, -d, and other file suffixes, such a script would be INVALUABLE for people looking to access pre-built Boost binaries for their projects. It would be an almost trivial task to implement such a script -- has there been any progress on this anywhere? Can I suggest that for MinGW, a native shell script, with file paths constructed relative to the boost-config path, would probably be the best way, rather than pkg-config, which is not available in MinGW/MSYS by default. Feel free to direct me to the online documentation of this stuff if it exists -- I couldn't find it though. Cheers JP -- John Pye Dept of Engineering Australian National University http://pye.dyndns.org/

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