August 2012 - Boost-users - lists.preview.boost.org

[fusion] for_each with indices
by Agustín K-ballo Bergé 01 Aug '12

01 Aug '12

I recently needed to iterate over a fusion sequence, calling a function for each element that depends not only on the element type but on its index (position within the sequence) as well. I didn't find anything readily available to use in conjunction with for_each, so I ended up using fold with the index as state. However, I would like to get the index as a compile time value. What would be the simpler/best way to do this? Creating an iterator adaptor that keeps track of advances to the base iterator (should I be using the iterator_facade extension mechanism)? Or perhaps zipping the sequence with some kind of infinite mpl::vector_c sequence? Agustín K-ballo Bergé.- http://fusionfenix.com

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Pool memory and std::forward_list
by Claude 01 Aug '12

01 Aug '12

Hi! I would create a memory pool for the node of a C++11 forward_list. It is possible use the BOOST pool memory with std::forward_list? -- View this message in context: http://boost.2283326.n4.nabble.com/Pool-memory-and-std-forward-list-tp46338… Sent from the Boost - Users mailing list archive at Nabble.com.

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Segfault when using date_time
by Sara Siegal 01 Aug '12

01 Aug '12

I attempted to rebuild my Boost installation with nanosecond support for the date-time library. I did so by adding BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG = 1 ; to boost-build.jam and adding <define>BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG to the jamfile in date_time/build. However, when I add this code to my application and compile, it segfaults: boost::posix_time::time_duration time1, time2; time1=boost::posix_time::seconds(3); std::cout << boost::posix_time::to_simple_string(time1) << std::endl; time2=boost::posix_time::nanoseconds(987654321); std::cout << boost::posix_time::to_simple_string(time2) << std::endl; boost::this_thread::sleep(time2); The segfault is at /archive/home/ssiegal/test/include/boost/date_time/posix_time/posix_time_config.hpp:99: (gdb) list 94 { 95 typedef gregorian::date date_type; 96 typedef time_duration time_duration_type; 97 simple_time_rep(date_type d, time_duration_type tod) : 98 day(d), 99 time_of_day(tod) 100 { 101 // make sure we have sane values for date & time 102 if(!day.is_special() && !time_of_day.is_special()){ 103 if(time_of_day >= time_duration_type(24,0,0)) { Anyone else ever see this? Is there anything else I need to do to turn on nanosecond resolution? Thanks very much!

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[boost] [type_erasure] Review ends today July 27, 2012
by Lorenzo Caminiti 01 Aug '12

01 Aug '12

Hello all, On Mon, Jul 23, 2012 at 9:09 AM, Lorenzo Caminiti <lorcaminiti(a)gmail.com> wrote: > On Wed, Jul 18, 2012 at 1:13 AM, Lorenzo Caminiti <lorcaminiti(a)gmail.com> wrote: >> *** The review of Steven Watanabe's proposed Boost.TypeErasure library >> begins on July 18, 2012 and ends on July 27, 2012. *** > > *** Boost.TypeErasure review ends in 5 days. Please submit your reviews :D *** *** Boost.TypeErasure review ends today July 27, 2012. If you are planning to submit a review, please do so as soon as possible. *** Thank you to everyone who has commented on the library and submitted a review so far! The review manager, --Lorenzo P.S. I am considering extending the review until end of day Sunday July 29, 2012... I will keep you posted. > There have been interesting discussions on the library on the ML but I > have not received any official review yet :( Especially if you are a > user of Boost Any, Function, and Any Iterator, you definitely want to > take a look at Type Erasure as it generalizes solutions provided by > those other libraries. > > Thank you. > > The review manager. > --Lorenzo > >> THE LIBRARY >> >> C++ provides runtime polymorphism through virtual functions. They are >> a very useful feature, but they do have some limitations. >> * They are intrusive. In generic programming, we can design an >> interface which allows third-party types to be adapted to it. >> * They require dynamic memory management. Of course, most of the >> problems can be avoided by using an appropriate smart pointer type. >> Even so, it still acts like a pointer rather than a value. >> * Virtual functions' ability to apply multiple independent concepts to >> a single object is limited. >> The Boost.TypeErasure library solves these problems allowing us to >> mirror static generic programming at runtime. >> >> Library source: >> http://svn.boost.org/svn/boost/sandbox/type_erasure/ >> >> Pre-built documentation: >> http://steven_watanabe.users.sourceforge.net/type_erasure/libs/type_erasure/ >> >> You can also download archives with pre-built documentation from: >> http://sourceforge.net/projects/steven-watanabe.u/files/ >> >> YOUR REVIEW >> >> Please submit a review to the mailing-list by replying to this email >> ("[boost] [type_erasure] Review ..." should be in the subject). >> >> Please state clearly whether you think this library should be accepted >> as a Boost library. >> >> Other questions you may want to consider: >> 1. What is your evaluation of the design? >> 2. What is your evaluation of the implementation? >> 3. What is your evaluation of the documentation? >> 4. What is your evaluation of the potential usefulness of the library? >> 5. Did you try to use the library? With what compiler? Did you have >> any problems? >> 6. How much effort did you put into your evaluation? A glance? A >> quick reading? In-depth study? >> 7. Are you knowledgeable about the problem domain? >> >> Thanks in advance to all who participate in the review discussion -- >> I'm looking forward to it!

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[Boost.Move] Conflict between std::move and boost::move (Boost 1.49.0)
by Jonathan Jones 01 Aug '12

01 Aug '12

Hi folks, Consider the following code (which distilled from a real world example): #include <boost/move/move.hpp> #include <boost/optional/optional.hpp> #include <utility> #include <vector> typedef boost::optional<int> data_type; typedef std::vector<data_type> vector_type; vector_type func() { vector_type vv; return move(vv); } If I compile this code using Boost 1.49 on Visual Studio 2010, or on a recent version of g++ (e.g. 4.7.1) which supports some C++11 features, the code fails to compile, complaining about ambiguity between std::move and boost::move. Strangely, the code compiles fine with Apple Clang version 3.1. Is there a way to work around the compilation problem which doesn't involve explicitly qualifying the calls to move? I'd prefer to use argument-dependent-lookup. Removing the includes of boost/move.hpp is not possible. In the real world example, that header is included indirectly. I did notice that if I define the macro BOOST_MOVE_USE_STANDARD_LIBRARY_MOVE, the compilation errors disappear. Is this the correct approach for compilers which support std::move? I find it odd that this macro isn't already defined for such compilers. Thanks in advance! Jon

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accumulators: not copying doubles into the acc set
by MM 01 Aug '12

01 Aug '12

Hello, Having a list of doubles stored somewhere, is there a way not to copy the doubles into the accumulator set and just iterate somehow through the existing data in order to save memory. Imagine I have a std::vector<double> with 10million entries. Then pushing each double to the accumulator set object, then I'd imagine, at one point, the process would hold the 10 million doubles twice. Rds, MM

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about how to install mpi of the boost1.49
by Kazuhide Ota 01 Aug '12

01 Aug '12

Dear all, Hello all, My name is Kazuhide Ota. I tryied to install boost1.49, but I got a problem. When I tried to install it on cygwin, I ran bootstrap.sh and bjam.exe, and I received the following message: <message> warning: skipping optional Message Passing Interface (MPI) library. note: to enable MPI support, add "using mpi ;" to user-config.jam. note: to suppress this message, pass "--without-mpi" to bjam. note: otherwise, you can safely ignore this message. MPI is necessary for me, so I added "using mpi : mpic++ ;" to user-config.jam in /boost_1_49_0/tools/build/v2, and I ran bjam.exe again. However, I received the same message. Did I edit the different file? If someone know hot to solve this problem, could you teach me? Best regards, Kazuide Ota

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program_options save config example
by Neil Nelson 01 Aug '12

01 Aug '12

This post goes toward providing a config or log file output of the input to Boost program_options. This was a requested capability but apparently without further work. See the lines under 'config out:' at the end. http://boost.2283326.n4.nabble.com/program-options-save-configuration-td256… The following Boost any page provides methods to convert the any values upon iterating the vm map. http://www.boost.org/doc/libs/1_50_0/doc/html/any/s02.html // program_options_wrapper.hpp // Latest boost program_options: // See http://boost-sandbox.sourceforge.net/doc/html/program_options.html // See http://svn.boost.org/svn/boost/trunk/libs/program_options/example/ #ifndef PROGRAM_OPTIONS_WRAPPER_HPP #define PROGRAM_OPTIONS_WRAPPER_HPP #include <boost/any.hpp> #include <boost/program_options.hpp> #include <string> namespace po = boost::program_options; class program_options_wrapper { public: po::variables_map vm; po::options_description cmd_line; po::options_description config; po::options_description hidden; po::options_description version; po::options_description all; // Singleton static program_options_wrapper& instance() { static program_options_wrapper instance_; return instance_; } bool initialize(int argc, char **argv); private: std::string config_file; // Singleton helpers program_options_wrapper() {} program_options_wrapper(program_options_wrapper const& copy); program_options_wrapper& operator=(program_options_wrapper const& copy); bool is_empty(const boost::any & operand); bool is_int(const boost::any & operand); bool is_double(const boost::any & operand); bool is_char_ptr(const boost::any & operand); bool is_string(const boost::any & operand); // void get_typeid(const boost::any & operand); }; // class program_options_wrapper #endif // #define PROGRAM_OPTIONS_WRAPPER_HPP // program_options_wrapper.cpp #include <boost/any.hpp> #include <boost/program_options.hpp> #include <string> #include <vector> #include <fstream> #include "program_options_wrapper.hpp" namespace po = boost::program_options; bool program_options_wrapper::initialize(int argc, char **argv) { version.add_options() ("version: program_options.cpp", "1.0") ("version: program_options.hpp", "1.0") ; cmd_line.add_options() ("help,h", "produce help message") ("version,v", "list component versions") ("config,c", "configuration file name") ("report,r", "report run options") ("vector,x", boost::program_options::value<std::vector<std::string> >(), "test string vector") ("double,d", boost::program_options::value<double>(), "test double") ; all.add(cmd_line).add(config).add(hidden); // po::store(po::parse_command_line(argc, argv, cmd_line), vm); // po::notify(vm); po::parsed_options parsed = po::command_line_parser(argc, argv).options(cmd_line).allow_unregistered().run(); po::store(parsed, vm); // po::store(po::command_line_parser(argc, argv).options(cmd_line).allow_unregistered().run(), vm); po::notify(vm); if (vm.count("config")) { std::ifstream ifs(config_file.c_str()); if (!ifs) { std::cout << "can not open config file: " << config_file << std::endl; return false; } else { po::store(parse_config_file(ifs, config), vm); po::notify(vm); } } if (vm.count("help")) { std::cout << all; return false; } if (vm.count("version")) { std::cout << version; return false; } if (vm.count("report")) { std::cout << all; std::cout << version << std::endl; std::cout << "command-line:"; for(int j=0;j<argc;j++) std::cout << " " << argv[j]; std::cout << std::endl << std::endl; std::cout << "config out:" << std::endl; for (po::variables_map::iterator it=vm.begin(); it != vm.end(); it++ ) { if (is_empty(it->second.value())) std::cout << "# " << it->first << "=is_empty" << std::endl; if (vm[it->first].defaulted()) std::cout << "# " << it->first << "=is_defaulted" << std::endl; if (is_int(it->second.value())) std::cout << it->first << "=" << vm[it->first].as<int>() << std::endl; else if (is_double(it->second.value())) std::cout << it->first << "=" << vm[it->first].as<double>() << std::endl; else if (is_char_ptr(it->second.value())) std::cout << it->first << "=" << vm[it->first].as<const char *>() << std::endl; else if (is_string(it->second.value())) { std::cout << it->first << "="; std::string temp = vm[it->first].as<std::string>(); if (temp.size()) std::cout << temp << std::endl; else std::cout << "true" << std::endl; } else { // Assumes that the only remainder is vector<string> std::vector<std::string> poVector = vm[it->first].as<std::vector<std::string> >(); for (std::vector<std::string>::iterator vecIt=poVector.begin() ; vecIt != poVector.end(); vecIt++ ) std::cout << it->first << "=" << (*vecIt) << std::endl; } } std::vector<std::string> unrecognized_options = po::collect_unrecognized(parsed.options, po::include_positional); if (unrecognized_options.size()) { std::cout << std::endl << "unrecognized options:"; for (int j=0;j<unrecognized_options.size();j++) std::cout << " " << unrecognized_options[j]; std::cout << std::endl; } std::cout << std::endl; } return true; } bool program_options_wrapper::is_empty(const boost::any & operand) { return operand.empty(); } bool program_options_wrapper::is_int(const boost::any & operand) { return operand.type() == typeid(int); } bool program_options_wrapper::is_double(const boost::any & operand) { return operand.type() == typeid(double); } bool program_options_wrapper::is_char_ptr(const boost::any & operand) { try { boost::any_cast<const char *>(operand); return true; } catch(const boost::bad_any_cast &) { return false; } } bool program_options_wrapper::is_string(const boost::any & operand) { return boost::any_cast<std::string>(&operand); } /* void program_options_wrapper::get_typeid(const boost::any & operand) { std::cout << operand.type().name() << std::endl; } */ // test.cpp /* program_options.o: program_options_wrapper.hpp program_options_wrapper.cpp g++-4.7 -g -c -Wall -std=c++11 program_options_wrapper.cpp -o \ program_options_wrapper.o test: test.cpp program_options_wrapper.o g++-4.7 -Wall -g -std=c++11 test.cpp -o test \ program_options_wrapper.o -lboost_program_options */ #include <boost/program_options.hpp> #include <iostream> #include "program_options_wrapper.hpp" int main(int argc, char **argv) { auto& po_wrap = program_options_wrapper::instance(); po_wrap.version.add_options()("version: build_state_tree.cpp", "1.0"); if (!po_wrap.initialize(argc, argv)) exit(0); return 1; } // test output -h [ --help ] produce help message -v [ --version ] list component versions -c [ --config ] configuration file name -r [ --report ] report run options -x [ --vector ] arg test string vector -d [ --double ] arg test double --version: build_state_tree.cpp 1.0 --version: program_options.cpp 1.0 --version: program_options.hpp 1.0 command-line: ./build_state_tree -r -x str1 -x str2 -d 345.67 -z testing config out: double=345.67 report=true vector=str1 vector=str2 unrecognized options: -z testing Neil Nelson

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