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

Serializing a vector containing an unsupported data type
by Tim Burgess 13 May '12

13 May '12

Hi, I have a vector: Std::vector <std::pair< std::string, wxAny> > myParameters; I need to serialize this as part of the class it belongs to and I'm confused as to how to do it, given that the wxWidgets wxAny class isn't supported by Boost. A colleague suggested using lexical cast and I think I can see how this would help if I was just serializing an individual wxAny variable, but how would I cope with it within the vector? I'm serializing out to XML, if this is an issue. Can anybody help, please? Best wishes. Tim Burgess Raised Bar Ltd Phone: +44 (0)1827 719822 Don't forget to vote for improved access to music and music technology at <http://www.raisedbar.net/petition.htm> http://www.raisedbar.net/petition.htm

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[interprocess] interprocess_barrier missing
by Sebastian Messerschmidt 12 May '12

12 May '12

Hello, I just upgraded my boost version from 1.42 to 1.49. Unfortunately the interprocess_barrier is not longer part of the interprocess library. I've checked the SVN and the file /boost/interprocess/sync/interprocess_barrier has been removed in revision 76106. Is there a reason for the removal? Or can someone point me to replacement? Right now I can live without it, but in order to get some of my components working again, I need a shared memory barrier. Any hints? cheers Sebastian

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Boost libraries on MacOS X: libboost_foo.dylib vs libboost_foo-mt.dylib (+)
by Nick Zavaritsky 12 May '12

12 May '12

Hi all! Please enlighten me what is the difference between libboost_foo.dylib and libboost_foo-mt.dylib? I guess -mt naming convention originates from Windows which once had both signle- and multithreaded CRT (-mt). However there is neither a single-threaded CRT nor a single-threaded program on Mac, thanks to GCD. Is there any use for non-MT libboost_foo.dylib or not? And let me squeeze another vaguely related question in the same letter. Are Boost debug and normal library variants binary-compatible? The reason I am curious is because Mac dynamic library linker (dyld) has a promising feature to load a different library variant without program recompilation. This feature is activated through the environment variable DYLD_IMAGE_SUFFIX. Ex: setting DYLD_IMAGE_SUFFIX=_debug will result in dyld attempting to load libfoo_debug.dylib instead of libfoo.dylib. Thanks in advance.

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BGL: get(p, g, x) and get(get(p, g), x)
by Shaun Jackman 11 May '12

11 May '12

Hi, I’ve implemented a graph that’s quite similar to adjacency_list. get(get(vertex_index, g), u) works as expected, but get(vertex_index, g, u) does not work. Is their a default implementation in boost/graph somewhere that translates the latter call to the first, or does my graph have to implement the following function? template <typename Tag, typename Key> typename property_map_value<MyGraph, Tag>::type get(Tag tag, const MyGraph& g, Key key) { return get(get(tag, g), key); } When I include this implementation, the get(tag, g, u) call works as expected. Cheers, Shaun

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multiprecision (/sandbox/big_number/) - pow function
by Ryan Lichtenwalter 11 May '12

11 May '12

I am using the multiprecision library from /sandbox/big_number compiling with boost 1.49.0. Specifically, I am using cpp_int. I can successfully compile and run the following example: #include <boost/multiprecision/cpp_int.hpp> using namespace boost::multiprecision; cpp_int u = 1; for(unsigned i = 1; i <= 100; ++i) u *= i; std::cout << u << std::endl; // prints 100! which I obtained from: https://svn.boost.org/svn/boost/sandbox/big_number/libs/multiprecision/doc/… When I add the following code: cpp_int x; x = pow( u, 2 ); I receive the following compiler error (g++ 4.1.2): ./boost/boost/multiprecision/detail/functions/pow.hpp: In function ‘void boost::multiprecision::default_ops::eval_pow(T&, const T&, const U&) [with T = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, U = int]’: ./boost/boost/multiprecision/detail/default_ops.hpp:1250: instantiated from ‘void boost::multiprecision::detail::pow_funct<Backend>::operator()(Backend&, const Backend&, const Arithmetic&) const [with Arithmetic = int, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >]’ ./boost/boost/multiprecision/mp_number.hpp:1089: instantiated from ‘void boost::multiprecision::mp_number<Backend, ExpressionTemplates>::do_assign_function_2(const F&, const Exp1&, const Exp2&, const boost::multiprecision::detail::terminal&, const boost::multiprecision::detail::terminal&) [with F = boost::multiprecision::detail::pow_funct<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> > >, Exp1 = boost::multiprecision::detail::mp_exp<boost::multiprecision::detail::terminal, boost::multiprecision::mp_number<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, true>, void, void>, Exp2 = boost::multiprecision::detail::mp_exp<boost::multiprecision::detail::terminal, int, void, void>, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, bool ExpressionTemplates = true]’ ./boost/boost/multiprecision/mp_number.hpp:1084: instantiated from ‘void boost::multiprecision::mp_number<Backend, ExpressionTemplates>::do_assign_function(const Exp&, const mpl_::int_<3>&) [with Exp = boost::multiprecision::detail::mp_exp<boost::multiprecision::detail::function, boost::multiprecision::detail::pow_funct<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> > >, boost::multiprecision::mp_number<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, true>, int>, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, bool ExpressionTemplates = true]’ ./boost/boost/multiprecision/mp_number.hpp:973: instantiated from ‘void boost::multiprecision::mp_number<Backend, ExpressionTemplates>::do_assign(const Exp&, const boost::multiprecision::detail::function&) [with Exp = boost::multiprecision::detail::mp_exp<boost::multiprecision::detail::function, boost::multiprecision::detail::pow_funct<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> > >, boost::multiprecision::mp_number<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, true>, int>, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, bool ExpressionTemplates = true]’ ./boost/boost/multiprecision/mp_number.hpp:570: instantiated from ‘void boost::multiprecision::mp_number<Backend, ExpressionTemplates>::do_assign(const boost::multiprecision::detail::mp_exp<tag, Arg1, Arg2, Arg3>&, const mpl_::true_&) [with tag = boost::multiprecision::detail::function, Arg1 = boost::multiprecision::detail::pow_funct<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> > >, Arg2 = boost::multiprecision::mp_number<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, true>, Arg3 = int, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, bool ExpressionTemplates = true]’ ./boost/boost/multiprecision/mp_number.hpp:95: instantiated from ‘boost::multiprecision::mp_number<Backend, ExpressionTemplates>& boost::multiprecision::mp_number<Backend, ExpressionTemplates>::operator=(const boost::multiprecision::detail::mp_exp<tag, Arg1, Arg2, Arg3>&) [with tag = boost::multiprecision::detail::function, Arg1 = boost::multiprecision::detail::pow_funct<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> > >, Arg2 = boost::multiprecision::mp_number<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, true>, Arg3 = int, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, bool ExpressionTemplates = true]’ vcp_translator_test.cpp:24: instantiated from here ./boost/boost/multiprecision/detail/functions/pow.hpp:89: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>’ Different invocations of pow with the arbitrary precision argument as the base, exponent, or both yield different compiler errors, but all of them seem to be broken. Am I doing something wrong? Is there some other fast way to achieve exponentiation with this library? Thanks, Ryan

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Interval Timers - Boost 1.49.0
by asif saeed 11 May '12

11 May '12

Hi, >From 1.49.0 release notes: "ASIO : Added a new class template basic_waitable_timer based around the C++11 clock type requirements. It may be used with the clocks from the C++11 <chrono> library facility or, if those are not available, Boost.Chrono. The typedefs high_resolution_timer, steady_timer and system_timer may be used to create timer objects for the standard clock types". I haven't yet looked into these facilities much - I only want to know if I can use any one or more of these facilities to create a periodic interval timer that could call my callback after every, say, 10 milliseconds. Has this been incorporated? Someone in an earlier thread said that ASIO deadline timer could be used but that doesn't work if system clock gets modified by the code itself. I look forward to receiving your feedback on this. -Asif

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[BGL] remove all children of a given vertex in a directed graph
by NsPx 11 May '12

11 May '12

Hi all, I would like to delete a vertex and all its children vertices in a directed graph. For example, 0 <-- 1 1 <-- 2 1 <-- 3 3 <-- 5 0 <-- 4 Removing 1 will remove 2, 3, 5 too. I have read the doc which explains how to remove all vertices from a graph but for my case it's a little more complicated and I can't find a clean way to do it. Thanks by advance for helping me. Here is what I planned to do but it isn't working : ### typedef adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, vertex_info> Graph; typedef Graph::vertex_descriptor vertexGraph; Graph* myGraph; //given graph vertexGraph vpos; //given vertex vector<vertexGraph> vertsLvl, allChildren; vector<vertexGraph>::iterator it, ite; vertsLvl.push_back(vpos); while( !vertsLvl.empty() ) { vector<vertexGraph> tmp; // all children of the vertsLvl's vertices for( it=vertsLvl.begin(), ite=vertsLvl.end(); it!=ite; ++it) { vector<vertexGraph> children; this->getChildren(*it, children); allChildren.insert( allChildren.end(), children.begin(), children.end()); tmp.insert( tmp.end(), children.begin(), children.end()); // remove edges between vertices from vertsLvl and their children clear_in_edges(*it, *myGraph); } vertsLvl = tmp; } // remove all children and the given vertex : doesn't work for( it=allChildren.begin(), ite=allChildren.end(); it!=ite; ++it) { remove_vertex(*it, *myGraph); } ###

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The callback of the timer inside a thread is not called
by mozdemir 11 May '12

11 May '12

Hi, I am trying to make the attached code run but no luck. I use the compiler, gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3. I tried all combinations. The timer callback, handle_timeout is never called. The weird thing is that the similar code in windows using msvc works fine. Could anybody help me out to figure out the issue in the code below? Thanks a lot in advance, mustafa ============================================================ #include <boost/asio.hpp> #include <boost/thread.hpp> #include <boost/date_time.hpp> #include <boost/date_time/gregorian/gregorian.hpp> #include <ctime> #include <iostream> struct time_t_traits { // The time type. typedef std::time_t time_type; // The duration type. struct duration_type { duration_type() : value(0) {} duration_type(std::time_t v) : value(v) {} std::time_t value; }; // Get the current time. static time_type now() { return std::time(0); } // Add a duration to a time. static time_type add(const time_type& t, const duration_type& d) { return t + d.value; } // Subtract one time from another. static duration_type subtract(const time_type& t1, const time_type& t2) { return duration_type(t1 - t2); } // Test whether one time is less than another. static bool less_than(const time_type& t1, const time_type& t2) { return t1 < t2; } // Convert to POSIX duration type. static boost::posix_time::time_duration to_posix_duration( const duration_type& d) { return boost::posix_time::seconds(d.value); } }; typedef boost::asio::basic_deadline_timer< std::time_t, time_t_traits> time_t_timer; void handle_timeout(const boost::system::error_code&) { std::cout << "handle_timeout\n"; } boost::asio::io_service io_service; void workerFunc() { using namespace boost::gregorian; boost::posix_time::seconds workTime(8); std::cout << "Worker: running" << std::endl; try { boost::asio::strand io_strand(io_service); time_t_timer timer(io_service); timer.expires_from_now(5); std::cout << "Starting synchronous wait\n"; timer.wait(); std::cout << "Finished synchronous wait\n"; timer.expires_from_now(5); std::cout << "Starting asynchronous wait\n"; // timer.async_wait(&handle_timeout); // timer.async_wait(&handle_timeout); // std::cout << "current UTC time is '" << to_simple_string(microsec_clock::universal_time()) << "'" << std::endl; // std::cout << "current local time is '" << to_simple_string(microsec_clock::local_time()) << "'" << std::endl; std::cout << "timer is set to expire at '" << timer.expires_at() << "'" << std::endl; timer.async_wait(io_strand.wrap(&handle_timeout)); std::cout << "Finished asynchronous wait\n"; } catch (std::exception& e) { std::cout << "Exception: " << e.what() << "\n"; } // Pretend to do something useful... boost::this_thread::sleep(workTime); std::cout << "Worker: finished" << std::endl; while(true) { boost::this_thread::sleep(boost::posix_time::seconds(1)); } } int main(int argc, char* argv[]) { std::cout << "main: startup" << std::endl; boost::thread thrd_io(boost::bind(&boost::asio::io_service::run, &io_service)); std::cout << "main: after thrd_io" << std::endl; boost::thread workerThread(workerFunc); std::cout << "main: after workerThread" << std::endl; // std::cout << "main: waiting for thread" << std::endl; while ( true ) { try { // io_service.poll(); io_service.run(); // boost::this_thread::sleep(boost::posix_time::milliseconds( 20 )); } catch (const boost::thread_interrupted&) { // Thread interruption request received, break the loop std::cout << "[" << boost::this_thread::get_id() << "] WorkerThread Thread interrupted. Exiting thread."; break; } catch ( std::exception & ex ) { std::cout << "[" << boost::this_thread::get_id() << "] Exception: " << ex.what(); } } workerThread.join(); std::cout << "main: done" << std::endl; return 0; } ===================================================== this is the output when the exe file is run. You don't see this line: "handle_timeout" ===================================================== $./timer main: startup main: after workerThread main: after thrd_io Worker: running Starting synchronous wait Finished synchronous wait Starting asynchronous wait timer is set to expire at '1336627143' Finished asynchronous wait Worker: finished -- View this message in context: http://boost.2283326.n4.nabble.com/The-callback-of-the-timer-inside-a-threa… Sent from the Boost - Users mailing list archive at Nabble.com.

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How can i install 32bit libboost lib on Debian6-64bit platform
by clive 11 May '12

11 May '12

Hi,all friends I build my project on Debian6-32bit platform, It works ok. I copy the build result to Debian6-64bit platform and run, it shows:error while loading shared libraries:libboost_regex.so.1.42.0:can not open shared object file:No such file or directory Then i do whereis libboost_regex.so.1.42.0, it shows: libboost_regex.so.1.42: /usr/lib/libboost_regex.so.1.42.0 /usr/lib64/libboost_regex.so.1.42.0 Then i add /usr/lib/ in ld.so.conf, then i run my project, it shows:error while loading shared libraries: libboost_regex.so.1.42.0: wrong ELF class: ELFCLASS64 I'm sure that install libboost-regex on Debian6-64bit platform, the lib don't compatible 32bit. How can i install 32bit libboost lib on Debian6-64bit platform?

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Re: [Boost-users] Is boost::asio::ip::tcp::iostream thread safe?
by boost 11 May '12

11 May '12

Thank you all ----- Original Message -----From: Michael Chisholm <chisholm(a)mitre.org> To: boost-users(a)lists.boost.org On 5/10/2012 5:34 PM, Michael Chisholm wrote: > On 5/10/2012 10:38 AM, Igor R wrote: >>> hi all, >>> I use ip::tcp::iostream but I don't know if it is thread safe, and I >>> cannot find the answer in boost document. >>> I read from ip::tcp::iostream in the receiver thread, and send >>> request in another thread. >>> Now I protected the stream with a mutex. But the problem is that, if >>> I do not send request, the server will not response, >>> and the receiver will block on read with lock, and the sender cannot >>> hold the lock and cannot send the request, deadlock. >>> >>> Is there anyone know that? Please kindly give me an answer. >> >> >> As far as I can see, it's not thread-safe. >> _______________________________________________ >> Boost-users mailing list >> Boost-users(a)lists.boost.org >> http://lists.boost.org/mailman/listinfo.cgi/boost-users >> >> > > Definitely not. I had to create my own socket-based stream with > boost.iostreams to avoid crashes. > > Andy I should add that boost.iostreams isn't thread-safe either. But you can create different istream and ostream objects which wrap the same underlying raw socket descriptor, to get concurrent reads and writes to the socket. Andy _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Is boost::asio::ip::tcp::iostream thread safe?
by boost 10 May '12

10 May '12

hi all, I use ip::tcp::iostream but I don't know if it is thread safe, and I cannot find the answer in boost document. I read from ip::tcp::iostream in the receiver thread, and send request in another thread. Now I protected the stream with a mutex. But the problem is that, if I do not send request, the server will not response, and the receiver will block on read with lock, and the sender cannot hold the lock and cannot send the request, deadlock. Is there anyone know that? Please kindly give me an answer. Best Regards Zhanwei Wang

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[Boost users] [ublas] Type conversion warning with ublas::bounded_vector
by Matija Kecman 10 May '12

10 May '12

Hi Boost users! Is there a way for boost.ublas to warn of type conversions with ublas::bounded_vector's? I'm using this library for scientific computations and I came across this problem, I have quite a large code so I would be useful to know if this mistake occurs elsewhere. Here is a code example: int main() { double d = M_PI; unsigned u = d; cout << "d = " << d << endl; cout << "u = " << u << endl; bounded_vector<double,3> dVec = ublas::scalar_vector<double>(3,M_PI); bounded_vector<unsigned,3> uVec = dVec; // ATTENTION: type conversion! cout << "dVec = " << dVec << endl; cout << "uVec = " << uVec << endl; return 0; } When I compile this using g++ 4.6.1: g++ -g3 -Wall -Wextra -ansi -pedantic -Wconversion -std=c++0x test.cpp -o test I get the following warnings: test.cpp: In function ‘int main()’: test.cpp:11:22: warning: conversion to ‘unsigned int’ from ‘double’ may alter its value [-Wconversion] Program output: $ ./test d = 3.14159 u = 3 dVec = [3](3.14159,3.14159,3.14159) uVec = [3](3,3,3) The compiler produced a warning for the conversion of the scalars but there was no warning for the ublas conversion, is there a way of having the compiler write a warning in that case? -Wconversion or any of the other options don't do this. Best, Matija

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[Boost users] [Program_options] Is Boost.Program_options available as a header?
by Matija Kecman 10 May '12

10 May '12

Hi Boost users, I'm quite new to boost. I have written a program using the Boost Program Options library. In order to compile it I have to link with the boost program options library. I would like to run my program on a computer which only has access to boost headers. I was wondering if the program options library is available as a header only? If not, it would be interesting to know the reason for that :) Best, Matija

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time variant uuid
by Victor Whiskey Yankee 10 May '12

10 May '12

Hello List, How can I create uuids so that the first one compares less than the next one.. something like this: boost::uuids::t1 = boost::uuids::random_generator()(); boost::uuids::t2 = boost::uuids::random_generator()(); BOOST_REQUIRE (t1 < t2); I don't see how to replace random_generator() with a time-based variant, if that even makes sense. If this can be done, then is there a way to extract the date+time from it? Thanks, Vic

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[Pool] Why is pool allocator slower than ordinary allocator?
by Mr.C64 10 May '12

10 May '12

Please see this thread on StackOverflow: http://tinyurl.com/chh4yxj Thanks.

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[Statechart] Pass variable parameter to Player ctor?
by Dick Bridges 10 May '12

10 May '12

In the PingPong example, I'm trying to pass a std::string variable to the Player ctor through the fifo_schedular<>create_processor<>() in main(). No joy. Error: no matching signature. I'm missing something obvious. I've stared at that first override in the boost header and tried everything I could think of. Dead give away that I don't understand: I'm "trying" things. %>[ I'd sure appreciate it if someone could point me in the right direction. Are there async examples that pass variables through create_processor() to the ctorS? Thanks for taking the time to read this, Dick

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[build] How can I change how the linker is called?
by Daryle Walker 10 May '12

10 May '12

This is for my PowerPC Tiger Mac system. I've installed GCC 4.7 fromMacPorts on it. I have it set in C++11 mode. Yesterday, I wrote on the list that I couldn't get the example file torun in my new trial project. (It's at<https://github.com/CTMacUser/Unionize>.) As soon as I added acompile-fail test and the corresponding line to Jamfile, everything worked! Sort of. The compile-fail test fails as expected (at compile-time).The example file still doesn't run due to a linking error I've seen before: //========================================[daryle@daryle-walkers-emac:test]$ b2 toolset=gcc-4.7...found 30 targets......updating 14 targets...common.mkdir bincommon.mkdir bin/super_union_basics.testcommon.mkdir bin/super_union_basics.test/gcc-4.7common.mkdir bin/super_union_basics.test/gcc-4.7/debuggcc.compile.c++ bin/super_union_basics.test/gcc-4.7/debug/super_union_basics.ogcc.link bin/super_union_basics.test/gcc-4.7/debug/super_union_basicsld: unknown option: --start-groupcollect2: error: ld returned 1 exit status "g++-mp-4.7" -o "bin/super_union_basics.test/gcc-4.7/debug/super_union_basics" -Wl,--start-group "bin/super_union_basics.test/gcc-4.7/debug/super_union_basics.o" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -g ...failed gcc.link bin/super_union_basics.test/gcc-4.7/debug/super_union_basics......skipped <pbin/super_union_basics.test/gcc-4.7/debug>super_union_basics.run for lack of <pbin/super_union_basics.test/gcc-4.7/debug>super_union_basics...common.mkdir bin/super_union_fail_test.testcommon.mkdir bin/super_union_fail_test.test/gcc-4.7common.mkdir bin/super_union_fail_test.test/gcc-4.7/debuggcc.compile.c++ bin/super_union_fail_test.test/gcc-4.7/debug/super_union_fail_test.oIn file included from super_union_fail_test.cpp:9:0://======================================== Now "ld" points to a version of ld64 from MacPorts, but that error hasshown up before this. I don't think my versions of "ld" have"--start-group" or "--end-group" options. What should they be instead,and where do I make these changes? (Even if no one here can answer thefirst part, they should be able to answer the second. That's where I'llmake the changes if I have to ask about the first part elsewhere.) Oh, I've uploaded the version of the project used here. Its SHA ID is"535241c3f13a9488bd845549ce3b1cf661ffcbac". (It's the latest as of this writing.) Daryle W.

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filesystem V3 path::normalize deprecated
by Shai Shasag 09 May '12

09 May '12

I have a question regarding the deprecated function path::normalize(). Before moving to V3 I used this function to resolve paths containing "..". For example: path myPath("/Dir_A/Dir_B/a.txt/.."); myPath->normalize(); now myPath is: "/Dir_A/Dir_B" How can this be done using V3 code? Thanks, Shai PS: Could not find in docs why this function was deprecated and what replacement available.

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c++ serial com connection
by Evaggelos Tsampazis 09 May '12

09 May '12

Hi! I would like to ask if I can use the boost libraries on the IDE environment of GodeGear RAD studio (C++ builder) 2009? I included the header file <boost/asio.hpp> but I got some compilation errors. I would like to use the boost libraries to make a connection to the mobile phone (via USB) to send and receive AT Commands to it. The asio part is the best boost solution for my case. Can anyone help to explain how to make boost libraries work in the environment I am working in? Thanks, Evaggelos

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[MSM] What's the easiest way to share data between states in a Boost.MSM state machine?
by B. Tommy Jensen 08 May '12

08 May '12

As the subject indicates, I'm trying to find the best way to share data between states in a MSM state machine. My first attempt has been to let each sub-machine and state inherit from a common base class, e.g.: struct MyStateMachine_ : public msm::front::state_machine_def<MyStateMachine_,CommonBaseClass> My idea is to add a reference to some shared data in the base class, making it easy to access the shared data from any state. The shared data reference must be passed to the base class. Questions: 1. Is it possible to pass constructor parameters to the common base class' constructor? I have tried different options without success, it seems that the default constructor with no arguments is the only option. 2. If 1. is not possible, what is the best way to initialize the shared property correctly? For example an easy method to iterate over all defined states? (not only the active ones). I have tried to iterate over all states with get_state_by_id, but this method does not enter sub-machines' states. 3. In general, what is the preferred way of implementing shared data between state classes in Boost.MSM? It would have been natural to store the data in the root state, but I can't see that there is an easy way to get access to the root FSM. (only the "nearest parent" FSM in the hierarchy is passed to the various event handler methods). Regards, Tommy

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asio async_read_some handler called but has bad data
by Matt Fair 08 May '12

08 May '12

Hello, I have client/server code similar to the chat server, but I am using async_read_some/async_write_some. I am having a problem with my client when the server sends a bunch of data to it at one time. What happens is that it works for a while then readComplete is called with a full buffer and no error set, but my buffer has garbage and eventually causes my socket to crash. I wanted to check with everyone to see if they have seen this problem before, and if there is anything glaring that I'm doing wrong here with boost::asio. I noticed that in the http server it is using shared_from_this, is this necessary? If the server is sending the client data with async_write faster than I can processes it with async_read, could it cause some buffer overrun? Thanks, Matt My buffer is defined as a private array: static const unsigned int m_maxReadLength = 1024; // maximum amount of data to read in one operation char m_readBuffer[m_maxReadLength]; The client starts to read the socket with: void TCPSocket::readStart() { if(isOpen()) { // Start an asynchronous read and call read_complete when it completes or fails m_pSocket->async_read_some( boost::asio::buffer(m_readBuffer, m_maxReadLength), boost::bind( &TCPSocket::readComplete, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } } My readComplete method is: void TCPSocket::readComplete(const boost::system::error_code& error, size_t bytes_transferred) { // the asynchronous read operation has now completed or failed and returned an error if(!error && bytes_transferred <= m_maxReadLength) { //convert to string const string buffer(&m_readBuffer[0], &m_readBuffer[bytes_transferred]); //buffer eventually becomes junk ..... } else { //handle error } readStart(); //read some more data }

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boost graph: isomorphism SIGSEGV
by Vömel Christof (vome) 08 May '12

08 May '12

Hi, when testing boost graph 1.46 isomorphism on two graphs of size 11869 on x86_64-suse-linux, g++ 4.6.2, compiled at various levels of optimization, I consistently get the following error. (on very small graphs, everything seems to work) Could this be due to a problem of recursion/stack size due to the size of the graph? Up to what size of graph is the isomorphism program sure to work? Thanks, Chris Program received signal SIGSEGV, Segmentation fault. 0x00000000004099a6 in boost::iterator_core_access::equal<boost::detail::out_edge_iter<__gnu_cxx::__normal_iterator<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property>*, std::vector<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property>, std::allocator<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property> > > >, unsigned long, boost::detail::edge_desc_impl<boost::undirected_tag, unsigned long>, long>, boost::detail::out_edge_iter<__gnu_cxx::__normal_iterator<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property>*, std::vector<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property>, std::allocator<boost::detail::sei_<unsigned long, std::_List_iterator<boost::list_edge<unsigned long, boost::no_property> >, boost::no_property> > > >, unsigned long, boost::detail::edge_desc_impl<boost::undirected_tag, unsigned long>, long> > (f1=..., f2=...) at /usr/include/boost/iterator/iterator_facade.hpp:535 535 return f1.equal(f2);

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Aspen Meadows Resort suite available for up to 4 nights of C++Now Conference
by Pdruck 08 May '12

08 May '12

Hi. I reserved a suite at Aspen Meadows Resort for 4 nights, for the C++Now conference; Sunday night, May 13 – Wed night, May 16, leaving Thurs. May 17. But due to last minute pressing events in the office, I have to cancel my registration. Propose to switch my reservation to whomever might be attending. Win-win. I don’t lose a heft cancellation fee. You get a beautiful suite (having been there previously) and conveniently located to the conference at Physics Center. Regards. Phil

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Re: [Boost-users] Updating filesystem to V3 (boost 1.49) - normalize deprecated
by Shai Shasag 08 May '12

08 May '12

Thanks, Lars I defined the macros only for my code and now everything compiles. I have a question regarding the deprecated function path::normalize(). Before moving to V3 I used this function to resolve paths containing "..". For example: path myPath("/Dir_A/Dir_B/a.txt/.."); myPath->normalize(); now myPath is: "/Dir_A/Dir_B" Can this be done using V3 code? Thanks, Shai

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Use boost::object_pool can not quit clearly. Am I misusing?
by 文凯 08 May '12

08 May '12

I use boost::object_pool in my program, but I found some problems, it can not quit. Below is the code. Don't suggest me use boost::pool. The boost::pool is no problem, just discuss the boost::object_pool. Could anybody help me? #include <iostream> #include <boost/pool/object_pool.hpp> int main(void) { boost::object_pool<int> p; int count = 1000*1000; int** pv = new int*[count]; for (int i = 0; i < count; i++) pv[i] = p.construct(); for (int i = 0; i < count; i++) p.destroy(pv[i]); delete [] pv; return 0; } This program can not quit normally. Why? http://stackoverflow.com/questions/10491649/use-boostobject-pool-can-not-qu… -- Cheers & KaiWen

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