- Boost-users - lists.boost.org

Placeholders and iterator arithmetic in MPL
by Rob Platt 18 Aug '10

18 Aug '10

Hello folks. I'm trying to use the iter_fold and reverse_iter_fold algorithms in MPL, since I want to operate on sub-ranges of an input sequence. Now if I do just the trivial case of dereferencing the current element, then all is well: struct works { typedef typename reverse_iter_fold< T, vector_c<long>, push_front<_1, deref< _2 > > >::type type; }; I can successfully instantiate this with, for example, vector_c<int,1,2,3,4>. But when I do iterator arithmetic (e.g. prior, next or begin) I run into trouble: struct fails { typedef typename reverse_iter_fold< T, vector_c<long>, push_front<_1, deref< next<_2> > > >::type type; }; -- error messages about arg 3 - I suspect that prior is being applied to the placeholder arg type itself, not to the iterator. I'm wondering if I should be using lambda/apply, but I've tried that without success. What's a would-be template metaprogrammer to do? Regards Rob

3 2

[1.44] PDF build of documentation is now available
by John Maddock 18 Aug '10

18 Aug '10

The PDF build of the documentation for Boost-1.44 is now available for download from https://sourceforge.net/projects/boost/files/ The direct links are: https://sourceforge.net/projects/boost/files/boost-docs/1.44.0/boost_1_44_p… https://sourceforge.net/projects/boost/files/boost-docs/1.44.0/boost_1_44_p… https://sourceforge.net/projects/boost/files/boost-docs/1.44.0/boost_1_44_p… https://sourceforge.net/projects/boost/files/boost-docs/1.44.0/boost_1_44_p… As usual please note that this only includes the subset of Boost documentation that is authored in quickbook/boostbook/docbook and so has an automatic conversion to PDF format. Enjoy! Regards, John.

1 0

boost asio sequential?
by Lloyd 18 Aug '10

18 Aug '10

hi, I have a simple boost asio server (copied from asio sample), multiple clients can connect to the server, but the operation performed only in a sequential manner. that is only after completing the first reqest, the second one is performed. Is this the defined behavior? Thanks, Lloyd ______________________________________ Scanned and protected by Email scanner

3 4

thread problem - incorrect checksum for freed object - object was probably modified after being freed
by Kraus Philipp 17 Aug '10

17 Aug '10

Hi, I create some boost::threads: std::vector< worker<T,D> > l_worker; boost::thread_group l_threadgroup; for(std::size_t i=0; i < p_threads; ++i) { l_worker.push_back( worker<T,D>(p_iteration, p_stepsize, m_fulltable, m_derivation, m_optimize, m_static, p_batch) ); l_threadgroup.create_thread( boost::bind( &worker<T,D>::optimize, l_worker[i] ) ); } l_threadgroup.join_all(); In the constructor of my worker-object makes a copy of the parameters ( p_iteration = std::size_t, p_stepsize = T (double), p_batch = std::vector and the others are std::map): ... ) : m_iteration( p_iteration ), m_stepsize( p_stepsize ), m_symbols(), m_derivation(), m_initvalues(), m_staticvalues(), m_batch() { std::copy( p_derivation.begin(), p_derivation.end(), std::inserter(m_derivation, m_derivation.begin())); std::copy( p_initvalues.begin(), p_initvalues.end(), std::inserter(m_initvalues, m_initvalues.begin())); std::copy( p_syms.begin(), p_syms.end(), std::inserter(m_symbols, m_symbols.begin())); } in the optimize-method I use this code: GiNaC::exmap l_dynamic; // exmap is == std::map for(typename std::map<std::string, std::pair<T,T> >::iterator it = m_initvalues.begin(); it != m_initvalues.end(); ++it) l_dynamic[ m_symbols[it->first] ] = it->second.first; If I create only one thread, everything works fine. On more thread I'll get main(4398,0xa07ad720) malloc: *** error for object 0xd2b880: incorrect checksum for freed object - object was probably modified after being freed. *** set a breakpoint in malloc_error_break to debug My idea is to create p_threads number of my worker objects and add some data with the constructor parameters. Than I call the join_all method so every object can work with their own data and after join_all is finished I receive the data from every object. Can someone please explain to me what I did wrong. Thanks Phil

1 0

Problem with nested bind
by przemyslaw.sliwa＠uk.bnpparibas.com 17 Aug '10

17 Aug '10

Hello, I am trying to make a simple nested bind in boost. I have the fillowing structure: struct eventInterval { double start, finish, weight; }; and a typedef typedef boost::shared_ptr<eventInterval> eventIntervalPtr; and then I am trying to copy (actually push back to a vector) all elements which have weight > 0.0. I cannot sompile this bit of code: std::vector<eventIntervalPtr> posIntervals, negIntervals, intervals(eventPtr->decomposeIntervals(anchorDate, today)); std::transform(intervals.begin(), intervals.end(), std::back_inserter(posIntervals), boost::bind(std::greater<double>(), boost::bind(&eventInterval::weight, _1), 0.0)); Could someone help me with this issue? Thanks ___________________________________________________________ This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is prohibited. Please refer to http://www.bnpparibas.co.uk/en/information/legal_information.asp?Code=ECAS-… for additional disclosures.

2 1

Program Options of Filesystem Path's - confused!
by John Dlugosz 17 Aug '10

17 Aug '10

OK, If I take a po:wvalue<std::wstring>()->notifier(&datadir_set) the string gets passed to datadir_set, and within that function it implicitly converts the string to a fs::wpath instance to call set_me. It works as expected. void set_me (const fs::wpath& p); void datadir_set (const std::wstring& s) { wcout << L"** set data dir to " << s << L".\n"; set_me (s); } However, if I declare the program option as po::wvalue<fs::wpath>()->notifier(&set_me) then when it runs I get "invalid option value". It apparently can't convert the argv token into a wpath? But it's not a compile-time error so it thinks it knows how to, but gets an error actually doing it? I have no trouble passing long string literals to the constructor, e.g. fs::wpath f1 (L"C:\\here\\there.txt"); The program option takes "." on the command line just fine, so it's the specific value of the string it doesn't like! I tried with Unix-style slashes, with no difference. A little experimenting tells me that it doesn't like having spaces in the string! Note that the quotes are understood by the run-time library that calls main, so the whole string (without surrounding quotes) is present in one element of argv. It works just fine when taking the argument as a string. This seems like a bug, somewhere. --John TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

3 7

[1.44.0] Release 1.44.0 is now available
by Beman Dawes 17 Aug '10

17 Aug '10

Release 1.44.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains two new libraies (Meta State Machine & Polygon) and numerous enhancements and bug fixes for existing libraries. For details, including download links, see http://www.boost.org/users/download/version_1_44_0 The release can also be downloaded directly from SourceForge. See http://sourceforge.net/projects/boost/files/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Beman Dawes Daniel James Eric Niebler Rene Rivera Vladimir Prus

1 0

Trac needs more milestones?
by Paul A. Bristow 17 Aug '10

17 Aug '10

I note that a milestone for the next version 1.45? isn't available yet for Trac tickets. Would it be useful to create a few 'spares' 1.45, 1.46, 1.47 ... to avoid this problem each release? I think there is a case for more than one release ahead - sometime one knows that testing time is going to mean it will miss the next release, so setting a milestone further ahead makes perfect sense. (Rare 1.n.1 cases can be added too if they prove necessary). (And/or does adding new milestones need to go the (endless?) list of release managers tasks?) Thanks. Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

3 2

Program options: Set function for an option?
by Ingo Maindorfer 17 Aug '10

17 Aug '10

Hi! Let's assume we have this: (stolen from tutorial): // Declare the supported options. po::options_description desc("Allowed options"); desc.add_options() ("compression", po::value<int>(), "set compression level") ; po::variables_map vm; po::store(po::parse_command_line(ac, av, desc), vm); po::notify(vm); ... if (vm.count("compression")) { cout << "Compression level was set to " << vm["compression"].as<int>() << ".\n"; } else { cout << "Compression level was not set.\n"; } Is there a way to set a new int to "compression" programmatically like this: vm["compression"].set( 42 ) ? Best regards, Ingo

1 0

[Log] Some questions on severity_logger usage
by Olivier Tournaire 17 Aug '10

17 Aug '10

Hi all, I am trying to use Boost.Log for my application. The log code is in shared library (a plugin). Here is how I set up my .so logging, according to the documentation: // ville_numerique_logging.hpp #include <boost/log/common.hpp> #include <boost/log/core.hpp> #include <boost/log/trivial.hpp> #include <boost/log/filters.hpp> #include <boost/log/formatters.hpp> #include <boost/log/utility/init/to_file.hpp> enum severity_level { normal, notification, warning, error, critical }; BOOST_LOG_DECLARE_GLOBAL_LOGGER_INIT(my_logger, boost::log::sources::severity_logger< >) { boost::log::init_log_to_file ( boost::log::keywords::file_name = "/home/olivier/ville_numerique.log", boost::log::formatters::attr< unsigned int >("LineID"), boost::log::keywords::format = "[%TimeStamp%]: %_%" // log record format ); // boost::log::core::get()->set_filter // ( // boost::log::filters::attr< boost::log::trivial::severity_level >("Severity") >= boost::log::trivial::info // ); return boost::log::sources::severity_logger< >(); } In some of my method, I then try lo log: src::severity_logger< >& lg = my_logger::get(); BOOST_LOG_SEV(lg, normal) << "A regular message"; BOOST_LOG_SEV(lg, warning) << "Something bad is going on but I can handle it"; BOOST_LOG_SEV(lg, critical) << "Everything crumbles, shoot me now!"; But, nothing happens. The file is not created. If I uncomment the set_filter lines, it throws an exception: "Requested attribute value not found" Could you please help? I am fighting with this for a too long time now. Regards, Olivier ----------------------------------------------------- Olivier Tournaire MATIS - Institut Géographique National 73, Ave de Paris 94165 St Mandé cedex, France tel: (+33) 1 43 98 84 29 fax: (+33) 1 43 98 85 81

1 0