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Ranges and primitive arrays and argument forwarding
by John M. Dlugosz 11 Jul '11

11 Jul '11

In a nutshell, I want to use ranges to unify several different ways of representing "strings" in the program. This includes subranges of an existing sequence, so for consistancy a "fixed" sized container does not need a nul termination but can fill the container completely. The point here is that I want to treat arrays differently from pointers, which is unlike boost::as_literal. The idea is that I can apply a pre-conditioning function to any supported type, and get a iterator_range back out. Here is an example of a trivial function to test it out, that just returns the length: namespace internal { template <typename RangeT> size_t Strlen (RangeT s) { return boost::size(s); } } template <typename T> size_t Strlen (T s) { return internal::Strlen (internal::as_literal(s)); } For a more complex function, every argument that is meant to be a generalized "string" will be so-wrapped, and pass on to the underlying internal form which expects that they are all Ranges. The conditioning needed is almost the same as boost::as_literal, so I copied and modified that: template <typename CharT> inline boost::iterator_range<CharT> measure_fixed (CharT* p, std::size_t capacity) { // The deduced CharT will include the const if called on a const array. Char* found= std::find (p, p+capacity, CharT(0)); // the find algorithm naturally does what I want, returning the same 'end' if not found. return boost::iterator_range<CharT> (p, found); } // Copied directly from Boost: pointers and containers template< class Range > inline boost::iterator_range<typename boost::range_iterator<Range>::type> as_literal( Range& r ) { return boost::range_detail::make_range( r, boost::range_detail::is_char_ptr(r) ); } // Ditto, with const. Duplication needed because && not available on VS8 template< class Range > inline boost::iterator_range<typename boost::range_iterator<const Range>::type> as_literal( const Range& r ) { return boost::range_detail::make_range( r, boost::range_detail::is_char_ptr(r) ); } // Actual arrays: I want to treat differently from pointers. template <typename Char, std::size_t sz > inline boost::iterator_range<Char*> as_literal( Char (&arr)[sz] ) { return measure_fixed (arr, sz); } // Duplicate needed for const form. template< typename Char, std::size_t sz > inline boost::iterator_range<const Char*> as_literal( const Char (&arr)[sz] ) { return measure_fixed (arr, sz); } However, I find that it is NOT distinguishing arrays: char cA[4]= { 'a', 'b', 'c', 'd' }; // fixed size array, no termination size_t result= Strlen (cA); This is calling the regular form, not the arragy form. The top-level function's call to internal::as_literal is going to the first form, not the third. The parameter, r, is of type char*& from what the debugger tells me, so the template argument Range must be deduced as char*. The original Strlen see s as a char*, so it's already lost it at this point. If I have to write every top-level function to take separate array and non-array template forms, besides being less elegant it will be a combinitational explosion on functions that take multiple arguments. Is there a way around this that work in Visual Studio 2005 (a.k.a. VS8)? When the project finally moves to a newer compiler, does rvalue references ("perfect forwarding") fix this issue, or is it still losing the arrayness by design? Thanks, —John

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Re: [Boost-users] [PropertyTree] wasRE: [Program_options] sections in config files
by Sean Farrow 11 Jul '11

11 Jul '11

Hi: Ok, I've just takan a look at property tree and it seems to do what I want, however if I use xml, and for example have an element such as: <Person id=121> <Name="bla"/> <age=33/> </Person> How will propertytree handle the attribute on person, i.e the id member? Secondly, How do I go about having a number of person entries-i.e persons. I was thinking of using a vector of propertyTrees, will this work? Any help appreciated! Cheers Sean. > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Sebastian Redl Sent: 11 July 2011 13:43 To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [Program_options] sections in config files On 11.07.2011 14:34, Sean Farrow wrote: Hi: I'm new to using the program_options library. I have a requirement to use an ini file style configuration file. I have a file of the form: [Section 1] Key 1 =value1 Key2=value2 [section2] Key1=value1 Key2=value2 What I'd like to be able to do is: Firstly enumerate the sections assuming the form above. Then secondly enumerate the keys and values in any section of my coosing. Will program_options allow me to do this? No, but PropertyTree will. Sebastian

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Sleeping a Boost.thread for some Boost.date_time nanoseconds
by Emer Rodriguez Formisano 11 Jul '11

11 Jul '11

Good morning, I want a boost thread to sleep for some nanoseconds. The following code is a sample that compiles without errors. However, it does not work as expected and I cannot figure out why. It seems that the application get stacked when executes the instruction: sleep(time1) and it does not execute any thing else. #include <iostream> #include <boost/thread.hpp> #include <boost/date_time/posix_time/posix_time.hpp> #include <boost/date_time.hpp> //Building options: //-DBOOST_DATE_TIME_POSIX_TIME_STD_CONFIG -lboost_date_time-mt -lboost_thread-mt void replay() { boost::posix_time::time_duration time1, time2; time1=boost::posix_time::seconds(3); std::cout << boost::posix_time::to_simple_string(time1) << std::endl; boost::this_thread::sleep(time1); time2=boost::posix_time::nanoseconds(987654321); std::cout << boost::posix_time::to_simple_string(time2) << std::endl; boost::this_thread::sleep(time2); } int main(int argc, char* argv[]) { boost::thread replaythread(replay); replaythread.join(); return 0; } The BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG is a preprocessor definition required in order to work with nanoseconds (http://www.boost.org/doc/libs/1_44_0/doc/html/date_time/details.html#date_t…) The thread sleeps perfectly for 3 seconds if you remove the mentioned definition from the building options and if you also comment out the code related to nanoseconds (lines 15-17). Thank you very much for your time This question was also posted to stackoverflow (http://stackoverflow.com/questions/6636731/) -- Emer Rodríguez Formisano

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[Program_options] sections in config files
by Sean Farrow 11 Jul '11

11 Jul '11

Hi: I'm new to using the program_options library. I have a requirement to use an ini file style configuration file. I have a file of the form: [Section 1] Key 1 =value1 Key2=value2 [section2] Key1=value1 Key2=value2 What I'd like to be able to do is: Firstly enumerate the sections assuming the form above. Then secondly enumerate the keys and values in any section of my coosing. Will program_options allow me to do this? Cheers Sean.

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[Interprocess] : problem with large vector of maps in memory mapped file
by Steven Maenhout 11 Jul '11

11 Jul '11

Dear all, I'm using Boost 1.47 on Linux x86_64 in combination with gcc version 4.5.1. I'm trying to implement a large vector of maps in a memory mapped file. My code works fine on small example cases but crashes randomly when trying to store larger datasets. The application generally runs fine for a few days before a segementation fault occurs which makes debugging very time consuming. A trimmed down version of the code looks like this: typedef boost::interprocess::managed_mapped_file::segment_manager SegmentManager_t; typedef boost::interprocess::allocator<void, SegmentManager_t> VoidAllocator_t; typedef std::pair<const uint,double> MapValue_t; typedef boost::interprocess::allocator<MapValue_t , SegmentManager_t> MapValueAllocator_t; typedef boost::interprocess::map<uint,double,std::less<uint>,MapValueAllocator_t> Map_t; typedef boost::interprocess::allocator<Map_t,SegmentManager_t> MapAllocator_t; typedef boost::interprocess::vector<Map_t,MapAllocator_t> VectorofMaps_t; boost::interprocess::managed_mapped_file m_mfile=managed_mapped_file(open_or_create, TEMPFILEPATH, TEMPFILEPATHSIZE); VoidAllocator_t alloc_inst (m_mfile.get_segment_manager()); VectorofMaps_t* m_pS=m_mfile.construct<VectorofMaps_t>(anonymous_instance)(numsparserows,Map_t(std::less<uint>(),alloc_inst),alloc_inst); I've managed to obtain a stack trace which pinpoints the problem at the use of the function lower_bound: Map_t::iterator mapiter=(*m_pS)[row].lower_bound(col); I realize that such random segfaults could be the result of a hardware problem (memory corruption, cpu overheating, hard drive storing the memory mapped file (ssd)) but stress testing these components has not revealed any problems. I am therefore hoping that somebody would be able to get some more information from the stack trace provided below. Any help or advice on how to identify the problem would be greatly appreciated. Steven #0 0x0000000000720244 in std::less<unsigned int>::operator() (this=0x7fffffffc390, __x=@0x3ff07fcf9f552438, __y=@0x7fffffffc5c0) at /usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../include/c++/4.5.1/bits/stl_function.h:230 #1 0x0000000000721fc7 in boost::container::containers_detail::value_compare_impl<unsigned int, std::pair<unsigned int const, double>, std::less<unsigned int>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> > >::operator()<std::pair<unsigned int const, double>, unsigned int> (this=0x7fffffffc390, key1=..., key2=@0x7fffffffc5c0) at /home/smaenhout/c++/boost/include/boost/interprocess/containers/container/detail/tree.hpp:78 #2 0x0000000000721b4f in boost::container::containers_detail::rbtree<unsigned int, std::pair<unsigned int const, double>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> >, std::less<unsigned int>, boost::interprocess::allocator<std::pair<unsigned int const, double>, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0u>, 0ul>, boost::interprocess::iset_index> > >::key_node_compare<boost::container::containers_detail::value_compare_impl<unsigned int, std::pair<unsigned int const, double>, std::less<unsigned int>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> > > >::operator()<boost::container::containers_detail::rbtree_node<std::pair<unsigned int const, double>, boost::interprocess::offset_ptr<void> >, unsigned int> (this=0x7fffffffc390, key1=..., key2=@0x7fffffffc5c0) at /home/smaenhout/c++/boost/include/boost/interprocess/containers/container/detail/tree.hpp:337 #3 0x0000000000721747 in boost::intrusive::detail::key_nodeptr_comp<boost::container::containers_detail::rbtree<unsigned int, std::pair<unsigned int const, double>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> >, std::less<unsigned int>, boost::interprocess::allocator<std::pair<unsigned int const, double>, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family>, boost::interprocess::iset_index> > >::key_node_compare<boost::container::containers_detail::value_compare_impl<unsigned int, std::pair<unsigned int const, double>, std::less<unsigned int>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> > > >, boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::container::containers_detail::rbtree_node<std::pair<unsigned int const, double>, boost::interprocess::offset_ptr<void, long, unsigned long, 0u> >, boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void, long, unsigned long, 0u>, true>, (boost::intrusive::link_mode_type)0, boost::intrusive::default_tag, 3>, boost::container::containers_detail::node_compare<boost::container::containers_detail::value_compare_impl<unsigned int, std::pair<unsigned int const, double>, std::less<unsigned int>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> > >, boost::container::containers_detail:: rbtree_node<std::pair<unsigned int const, double>, boost::interprocess::offset_ptr<void, long, unsigned long, 0u> > >, unsigned long, true> > >::operator()<boost::interprocess::offset_ptr<boost::intrusive::compact_rbtree_node<boost::interprocess::offset_ptr<void> >, long, unsigned long, 0u>, unsigned int> (this=0x7fffffffc390, key1=..., key2=@0x7fffffffc5c0) at /home/smaenhout/c++/boost/include/boost/intrusive/detail/utilities.hpp:236 #4 0x00000000007213cc in boost::intrusive::detail::tree_algorithms<boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void, long, unsigned long, 0u>, true> >::lower_bound<unsigned int, boost::intrusive::detail::key_nodeptr_comp<boost::container::containers_detail::rbtree<unsigned int, std::pair<unsigned int const, double>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> >, std::less<unsigned int>, boost::interprocess::allocator<std::pair<unsigned int const, double>, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family>, boost::interprocess::iset_index> > >::key_node_compare<boost::container::containers_detail::value_compare_impl<unsigned int, std::pair<unsigned int const, double>, std::less<unsigned int>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> > > >, boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::container::containers_detail::rbtree_node<std::pair<unsigned int const, double>, boost::interprocess::offset_ptr<void> >, boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void>, true>, (boost::intrusive::link_mode_type)0, boost::intrusive::default_tag, 3>, boost::container::containers_detail::node_compare<boost::container::containers_detail::value_compare_impl<unsigned int, std::pair<unsigned int const, double>, std::less<unsigned int>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> > >, boost::container::containers_detail::rbtree_node<std::pair<unsigned int const, double>, boost::interprocess::offset_ptr<void> > >, unsigned long, true> > > > (header=..., key=@0x7fffffffc5c0, comp=...) at /home/smaenhout/c++/boost/include/boost/intrusive/detail/tree_algorithms.hpp:839 #5 0x0000000000720e32 in boost::intrusive::rbtree_algorithms<boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void, long, unsigned long, 0u>, true> >::lower_bound<unsigned int, boost::intrusive::detail::key_nodeptr_comp<boost::container::containers_detail::rbtree<unsigned int, std::pair<unsigned int const, double>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> >, std::less<unsigned int>, boost::interprocess::allocator<std::pair<unsigned int const, double>, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family>, boost::interprocess::iset_index> > >::key_node_compare<boost::container::containers_detail::value_compare_impl<unsigned int, std::pair<unsigned int const, double>, std::less<unsigned int>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> > > >, boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::container::containers_detail::rbtree_node<std::pair<unsigned int const, double>, boost::interprocess::offset_ptr<void> >, boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void>, true>, (boost::intrusive::link_mode_type)0, boost::intrusive::default_tag, 3>, boost::container::containers_detail::node_compare<boost::container::containers_detail::value_compare_impl<unsigned int, std::pair<unsigned int const, double>, std::less<unsigned int>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> > >, boost::container::containers_detail::rbtree_node<std::pair<unsigned int const, double>, boost::interprocess::offset_ptr<void> > >, unsigned long, true> > > > (header=..., key=@0x7fffffffc5c0, comp=...) at /home/smaenhout/c++/boost/include/boost/intrusive/rbtree_algorithms.hpp:470 #6 0x00000000007207f1 in boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::container::containers_detail::rbtree_node<std::pair<unsigned int const, double>, boost::interprocess::offset_ptr<void, long, unsigned long, 0u> >, boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void, long, unsigned long, 0u>, true>, (boost::intrusive::link_mode_type)0, boost::intrusive::default_tag, 3>, boost::container::containers_detail::node_compare<boost::container::containers_detail::value_compare_impl<unsigned int, std::pair<unsigned int const, double>, std::less<unsigned int>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> > >, boost::container::containers_detail::rbtree_node<std::pair<unsigned int const, double>, boost::interprocess::offset_ptr<void, long, unsigned long, 0u> > >, unsigned long, true> >::lower_bound<unsigned int, boost::container::containers_detail::rbtree<unsigned int, std::pair<unsigned int const, double>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> >, std::less<unsigned int>, boost::interprocess::allocator<std::pair<unsigned int const, double>, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family>, boost::interprocess::iset_index> > >::key_node_compare<boost::container::containers_detail::value_compare_impl<unsigned int, std::pair<unsigned int const, double>, std::less<unsigned int>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> > > > > (this=0x7fc8f21bef08, key=@0x7fffffffc5c0, comp=...) at /home/smaenhout/c++/boost/include/boost/intrusive/rbtree.hpp:1064 #7 0x00000000007202ec in boost::container::containers_detail::rbtree<unsigned int, std::pair<unsigned int const, double>, boost::container::containers_detail::select1st<std::pair<unsigned int const, double> >, std::less<unsigned int>, boost::interprocess::allocator<std::pair<unsigned int const, double>, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0u>, 0ul>, boost::interprocess::iset_index> > >::lower_bound (this=0x7fc8f21bef00, k=@0x7fffffffc5c0) at /home/smaenhout/c++/boost/include/boost/interprocess/containers/container/detail/tree.hpp:853 #8 0x000000000071fea8 in boost::container::map<unsigned int, double, std::less<unsigned int>, boost::interprocess::allocator<std::pair<unsigned int const, double>, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0u>, 0ul>, boost::interprocess::iset_index> > >::lower_bound ( this=0x7fc8f21bef00, x=@0x7fffffffc5c0) at /home/smaenhout/c++/boost/include/boost/interprocess/containers/container/map.hpp:638

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cann't compile Regular Expressions to Split a String code
by Eric Lin 11 Jul '11

11 Jul '11

Dear Boost programers: I copied a piece simple Using Regular Expressions to Split a String code from book(c++ cookbook) chapter 4 section 24, page 196-197, Example code 4.33 --------------------------------------------------------------------- // Example 4-33. Using Boost's regular expressions #include <iostream> #include <string> #include <boost/regex.hpp> int main() { std::string s= "who,lives:in-a,pineapple under the sea?"; boost::regex re(",|:|-|\\s+"); // Create the reg exp boost::sregex_token_iterator // Create an iterator using a p(s.begin(), s.end(), re, -1); // sequence and that reg exp boost::sregex_token_iterator end; // Crate an end_of_reg_exp // marker while (p != end) std::cout << *p++ << '\n'; } ------------------------ source code http://examples.oreilly.com/9780596007614/ > --------------------------------------------- > g++ 4-33.cpp > /tmp/ccx4JXEA.o: In function `boost::basic_regex<char, > boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign(char > const*, char const*, unsigned int)': > 4-33.cpp:(.text._ZN5boost11basic_regexIcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE6assignEPKcS7_j[boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign(char const*, char const*, unsigned int)]+0x22): undefined reference to `boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::do_assign(char const*, char const*, unsigned int)' > /tmp/ccx4JXEA.o: In function `bool > boost::regex_search<__gnu_cxx::__normal_iterator<char const*, > std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char > const*, std::basic_string<char, std::char_traits<char>, > std::allocator<char> > > > >, char, boost::regex_traits<char, > boost::cpp_regex_traits<char> > >(__gnu_cxx::__normal_iterator<char > const*, std::basic_string<char, std::char_traits<char>, > std::allocator<char> > >, __gnu_cxx::__normal_iterator<char const*, > std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >, boost::match_results<__gnu_cxx::__normal_iterator<char const*, > std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char > const*, std::basic_string<char, std::char_traits<char>, > std::allocator<char> > > > > >&, boost::basic_regex<char, > boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, > boost::regex_constants::_match_flags, __gnu_cxx::__normal_iterator<char > const*, std::basic_string<char, std::char_traits<char>, > std::allocator<char> > >)': > 4-33.cpp:(.text._ZN5boost12regex_searchIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS5_EEEcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEEEbT_SD_RNS_13match_resultsISD_T0_EERKNS_11basic_regexIT1_T2_EENS_15regex_constants12_match_flagsESD_[bool boost::regex_search<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >(__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::match_results<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > >&, boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::_match_flags, __gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >)]+0x6c): undefined reference to `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::find()' > /tmp/ccx4JXEA.o: In function > `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char > const*, std::basic_string<char, std::char_traits<char>, > std::allocator<char> > >, > std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char > const*, std::basic_string<char, std::char_traits<char>, > std::allocator<char> > > > >, boost::regex_traits<char, > boost::cpp_regex_traits<char> > > >::perl_matcher(__gnu_cxx::__normal_iterator<char const*, > std::basic_string<char, std::char_t > ------------------------------------------ Thanks your help a lot in advance, Eric

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Time classes and zoneinfo (tz/Olsen) database
by Dom Driver 10 Jul '11

10 Jul '11

Hi List, I'm currently working on a project with a requirement for up-to-date worldwide timezone information, including accurate daylight saving information. How well do the boost time classes handle the tz database? Can I populate the boost classes with up-to-date info easily? Has anyone done this? Ta! D

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[asio] sending and receiving binary
by Wilde, Donald S 10 Jul '11

10 Jul '11

Hello, all - After starting from scratch again, I've been able to climb into boost::asio and am beginning to get it to work. Please bear with me; I'm still a noob when it comes to reading C++ templates. I started by building the little asynchronous daytime server into my primary application, and used the asynch client to successfully talk to it. All well and good. Now, I've built my real message, which is mixed 7-bit ASCII and binary data (counts, checksums, etc.). In experimenting to make it work, I've started changing my code in the server and client to be more like the echo server. It appears to be accepting the message, but when it tries to respond the async_write() function throws an error: ERROR: 'system:0' has occurred. ... and I see 'connection reset by peer' on the client side. I don't THINK it's because I'm sending binary; this is more likely a glitch in my understanding of boost::asio. I'll back up and look at the daytime and echo examples again and try to see what I've messed up, but I thought I'd put this out there as I've been slogging in mud for a few hours now. :) // ---- server code ---- // server using boost::asio::ip::tcp; TCPConnection::TCPConnection(boost::asio::io_service& aIOService) : _socket(aIOService) { } boost::shared_ptr<TCPConnection> TCPConnection::Create(boost::asio::io_service& aIOService) { return boost::shared_ptr<TCPConnection>(new TCPConnection(aIOService)); } tcp::socket& TCPConnection::Socket() { return _socket; } void TCPConnection::CheckMessageAndRespond() { _message = make_my_daytime_string(); boost::asio::async_write( _socket, boost::asio::buffer(_message), boost::bind(&TCPConnection::HandleWrite, shared_from_this(), boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } void TCPConnection::HandleWrite( const boost::system::error_code& aError, std::size_t aNumBytes) { std::cerr << "ERROR: '" << aError << "' has occurred." << std::endl; } std::string TCPConnection::make_my_daytime_string() { std::time_t now = std::time(0); return std::ctime(&now); } static const int QUERYIPADDR = 2000; TCPServer::TCPServer(boost::asio::io_service& aIOService) : _acceptor(aIOService, tcp::endpoint(tcp::v4(), QUERYIPADDR)) { StartAccept(); } void TCPServer::StartAccept() { boost::shared_ptr<TCPConnection> newconnection = TCPConnection::Create(_acceptor.io_service()); _acceptor.async_accept( newconnection->Socket(), boost::bind(&TCPServer::HandleAccept, this, newconnection, boost::asio::placeholders::error)); std::cout << "Extender inquiry server ready for business!" << std::endl; } void TCPServer::HandleAccept( boost::shared_ptr<TCPConnection> aNewConnection, const boost::system::error_code& aError) { if (!aError) { aNewConnection->CheckMessageAndRespond(); StartAccept(); } } //---- main equiv (within another class) ---------------------- ExtenderServer::ExtenderServer(TVED::ITVExtenderDeviceHandler* aEDHandler) { try { boost::asio::io_service ioservice; TCPServer Server(ioservice); ioservice.run(); } catch (std::exception& e) { std::cerr << e.what() << std::endl; } } //-------- client (extracted code) ------------------------- string message; message.reserve(1024); ... size_t mlen = message.length(); const char* mptr = 0; mptr = message.data(); // Create new IO network client service boost::asio::io_service io_service; // Attach a Query Resolver to it tcp::resolver resolver(io_service); // We will talk to a Well Known Port (currently 2000) tcp::resolver::query query(tcp::v4(), argv[3], "2000"); tcp::resolver::iterator iterator = resolver.resolve(query); tcp::socket socket(io_service); socket.connect(*iterator); boost::system::error_code error; size_t lwrite = boost::asio::write(socket, boost::asio::buffer(mptr, mlen)); if (error) { throw boost::system::system_error(error); // Some error occurred. } cout << "Wrote " << lwrite << " bytes" << endl; char buf[1024]; size_t len; while (1) { char buf[1024]; len = socket.read_some(boost::asio::buffer(buf), error); if (error == boost::asio::error::eof) { cout << "eof" << endl; break; } else if (error) { throw boost::system::system_error(error); // Some other error. } } string response; stringstream sbuf (response, stringstream::in | stringstream::out | stringstream::binary); sbuf.write(buf, len); cout << endl << "Message string server returns: " << endl; print_message(&response); } catch (std::exception& e) { std::cerr << "ERR from faker: " << e.what() << std::endl; } // ---------------------------------run data ----------------------- // example data // as sent by client "faker" program Message string client sends: ASCII: I N T C :: :: :: / :: :: :: :: :: :: :: :: 0 0 : 1 3 : 2 0 : f 9 : 2 a : 8 9 | 1 9 2 . 1 6 8 . 0 . 1 0 | 3 0 0 0 F N :: H Binary: 49 4E 54 43 00 00 00 2F 00 00 00 00 00 00 00 00 30 30 3A 31 33 3A 32 30 3A 66 39 3A 32 61 3A 38 39 7C 31 39 32 2E 31 36 38 2E 30 2E 31 30 7C 33 30 30 30 46 4E 8D 48 Wrote 55 bytes ERR from faker: Connection reset by peer TIA for suggestions! :D -- Don Wilde

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[datetime] convert a int32_t to a time
by Sean Farrow 10 Jul '11

10 Jul '11

Hi: I'm working with a piece of code that gives me time as an int32_t I'd like to convert this in to a more intelligible form to store along with the current date. Does boost.datetime allow me to do this? Any help appreciated. Cheers Sean.

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[thread] terminating a thread when a program exits
by Sean Farrow 10 Jul '11

10 Jul '11

Hi: I've got a situation whereby, I've got a number of boost::thread objects being created by classes in my program and run for the duration of the program. What I need to do is when the exit menu item is activated, close down all threads. I was going to use a condition, and have the threads continue until the condition is signalled, and then use notify_all when the exit menu item is activated. Given that I want this condition to be multi-read/exclusive write, what mutex is the best option? Also will I need to use a mutex in the threads I need to terminate. I see the code of the threads being something like: While (Terminate !=false) { //perform actions. }; Normally in this situation I'd use a windows event and the WaitForSingle/multipleObject functions, but as this has to be cross platform I carn't do this. Any help with this appreciated. Cheers Sean.

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