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dynamic_bitset get block_type not ulong
by Michael Powell 05 Apr '13

05 Apr '13

Hello, How do I get at the block_type value itself, not an unsigned long, from a dynamic_bitset (or std::bitset for that matter). For instance, can I do something like this? typedef unsigned char byte; boost::dynamic_bitset<byte> my_bitset(static_cast<byte>(0x00)); //Do some bit twiddling... byte my_value = static_cast<byte>(my_bitset); Or something like that. Basically I want to avoid any to_ulong() mumbo jumbo if I can just get at the underlying block_type value. Thank you... Regards, Michael Powell

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Problem with Serialization: invalid signature
by Alexander Striffeler 04 Apr '13

04 Apr '13

Hi all I have some trouble with the serialization of objects in C++ using boost. Since there was some strange behaviour in the code, I tried to serialize and deserialize a sample object isolated trying two versions: |deSerialize(Packet p1, Packet p2){ // Version 1 using stringstreams std::ostringstream *serialized = new std::ostringstream[2];|| ||serialized[0]=std::ostringstream(std::ios_base::binary);|| ||serialized[1]=std::ostringstream(std::ios_base::binary);|| || || boost::archive::text_oarchive oa(serialized[0]);|| || oa << p1;|| || || boost::archive::text_oarchive oa2(serialized[1]);|| || oa2 << p2;|| || || std::string s1, s2;|| || || s1 = serialized[0].str();|| || s2 = serialized[1].str();|| || || //deserialize CCNDataPkt newPacket; std::istringstream inputStream(s2, std::ios_base::binary); boost::archive::text_iarchive ia(inputStream); | | ia >> newPacket;| // throws boost::archive::archive_exception: invalid signature. } and |deSerialize(Packet p1, Packet p2){ // Version 2 using ofstreams ||std::ofstream of("deleteme",std::ios_base::binary);|| || boost::archive::binary_oarchive oa(of);|| || oa << p1;|| || || std::ifstream ifstr("deleteme", std::ios_base::binary);|| || CCNDataPkt newp;|| || boost::archive::binary_iarchive ia(ifstr);|| | | ia >> newp;| // boost::archive::archive_exception: invalid signature. } However, both variants returned an invalid signature exception even though I haven't changed anything on the serialized data. Does anyone know what is wrong in either of the examples above? The methods for serializing the custom object 'Packet' are implemented according to the boost serialization tutorial (non-intrusive version splitted) Any hints are very much appreciated - TIA! Cheers, Alex

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[Parallel BGL] Error during building library
by Nikos Kyrtatas 04 Apr '13

04 Apr '13

In order to build Parallel BGL 0.7.0 beta, I first used cmake: ~/project/lib> cmake parallel-bgl-0.7.0/ -- The C compiler identification is GNU -- The CXX compiler identification is GNU -- Check for working C compiler: /usr/bin/cc -- Check for working C compiler: /usr/bin/cc -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Check for working CXX compiler: /usr/bin/c++ -- Check for working CXX compiler: /usr/bin/c++ -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Configuring done -- Generating done -- Build files have been written to: /home/nkyrtata/project/lib and then make: ~/project/lib> make -- Configuring done -- Generating done -- Build files have been written to: /home/nkyrtata/project/lib Scanning dependencies of target boost_graph_mpi [ 2%] Building CXX object libs/graph_parallel/src/CMakeFiles/boost_graph_mpi.dir/mpi_process_group.cpp.o [ 5%] Building CXX object libs/graph_parallel/src/CMakeFiles/boost_graph_mpi.dir/tag_allocator.cpp.o Linking CXX static library ../../../lib/libboost_graph_mpi.a [ 5%] Built target boost_graph_mpi Scanning dependencies of target adjlist_build_test [ 8%] Building CXX object libs/graph_parallel/test/CMakeFiles/adjlist_build_test.dir/adjlist_build_test.cpp.o In file included from /home/nkyrtata/project/lib/parallel-bgl-0.7.0/boost/graph/distributed/adjacency_list.hpp:3961:0, from /home/nkyrtata/project/lib/parallel-bgl-0.7.0/libs/graph_parallel/test/adjlist_build_test.cpp:10: /home/nkyrtata/project/lib/parallel-bgl-0.7.0/boost/graph/distributed/adjlist/serialization.hpp: In function ‘std::vector<int> boost::detail::parallel::available_process_files(const string&)’: /home/nkyrtata/project/lib/parallel-bgl-0.7.0/boost/graph/distributed/adjlist/serialization.hpp:97:61: error: conversion from ‘boost::filesystem3::path’ to non-scalar type ‘std::string {aka std::basic_string<char>}’ requested make[2]: *** [libs/graph_parallel/test/CMakeFiles/adjlist_build_test.dir/adjlist_build_test.cpp.o] Error 1 make[1]: *** [libs/graph_parallel/test/CMakeFiles/adjlist_build_test.dir/all] Error 2 make: *** [all] Error 2 I am using Ubuntu 11.10, gcc 4.6.1 and boost 1.52. Any help would be greatly appreciated.

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[program options] compile error if BOOST_NO_EXCEPTIONS defined
by Olaf Krzikalla 04 Apr '13

04 Apr '13

Hi, MSVC 2008, program_options/variables_map.cpp: try without catch error, if BOOST_NO_EXCEPTIONS is defined. Fixable by wrapping the try on line 46: + #ifndef BOOST_NO_EXCEPTIONS try + #endif Best Olaf

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[Boost.Coroutine] Problem compiling simple code with c++98 compiler
by Lukas Czaja 03 Apr '13

03 Apr '13

Hi, i was checking if my code is compatible with c++98 standard and i've encounterd compile error. With -std c++11 option everything works fine. Below i've written code causing same problem. #include <boost/coroutine/coroutine.hpp> #include <boost/coroutine/attributes.hpp> typedef boost::coroutines::coroutine<void( boost::system::error_code , std::size_t)> coro_t; struct coro_test{ coro_test() {} void coro_fun(typename coro_t::caller_type& ca)const{ boost::system::error_code ec; boost::tie(ec, boost::tuples::ignore) = ca.get(); ca(); } coro_t coro; }; int main(int argc, char *argv[]) { { boost::system::error_code ec; coro_t coro2; //default construction is ok coro_test ctest; //compile error , why ??? coro_t coro( boost::bind(&coro_test::coro_fun, &ctest, _1),coro_t::arguments( ec, 7)); coro = coro_t(boost::bind(&coro_test::coro_fun, &ctest, _1),coro_t::arguments( ec, 7)); } ... /usr/local/include/boost/type_traits/is_function.hpp:50: błąd:forming pointer to reference type 'boost::rv<boost::coroutines::coroutine<void(boost::system::error_code, long unsigned int)> >&' /usr/local/include/boost/type_traits/is_function.hpp:102: błąd:'value' is not a member of 'boost::detail::is_function_impl<boost::rv<boost::coroutines::coroutine<void(boost::system::error_code, long unsigned int)> >&>' /usr/local/include/boost/type_traits/is_convertible.hpp:354: błąd:'value' is not a member of 'boost::is_function<boost::rv<boost::coroutines::coroutine<void(boost::system::error_code, long unsigned int)> >&>' /usr/local/include/boost/utility/enable_if.hpp:59: błąd:'value' is not a member of 'boost::is_convertible<boost::coroutines::coroutine<void(boost::system::error_code, long unsigned int)>&, boost::rv<boost::coroutines::coroutine<void(boost::system::error_code, long unsigned int)> >&>' I work with Qt, g++ compiler on ubuntu 12.10 Is this library bug ?

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[serialization] serializing a pointer without causing object tracking
by Stefan Strasser 02 Apr '13

02 Apr '13

Hi everyone, Hi Robert, in case you'd like to answer this one, because I have a rather specific question about your library. Thank you in advance! I'd like to serialize an object and later reconstruct it from the serialized data: void save(T const &t){ ar << t; } T* load(){ T *t=new T(); //error ar >> *t; } T might not have a default constructor. so load_construct_data should be used. apparently the way to do this is to serialize through a pointer: void save(T const *t){ ar << t; } T *load(){ T *t; ar >> t; } this works, but it causes the type T to be tracked, if its object tracking is set to track_selectively. I don't want that. but I can't set it to track_never either, because if the type is serialized at another point in the program through a pointer, the type should be tracked. is there a solution to this? is there a serialization wrapper that says "don't track this type just because of this pointer"? what comes to mind as a solution is serializing as an object, and calling load/save_construct_data manually. but then there is another problem: void save(T const &t){ save_construct_data(t,version<T>::value); ar << t; } void load(T *unconstructed_t){ load_construct_data(unconstructed_t, ??? ); ar >> *t; } if the implementation level of T is object_class_info, the object version is loaded from the preamble when the object itself is loaded. there is no in between loading the version and loading the object, it's entirely handled in the non-header part of the library. so basically I have a solution when the implementation level is object_serializable (no version info, call load_construct_data manually), and when tracking is set to track_never (serialize as a pointer). but not for the default case, object_class_info with track_selectively. am I missing something? Stefan

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Problems with stl::map
by Michael Powell 02 Apr '13

02 Apr '13

Hello, Perhaps there is a boost answer for this, I don't know. I have a typedef unsigned char byte defined in global scope. Then a typedef byte address_type defined in the scope of a class. I'd like to setup a std::map<address_type, byte> if at all possible. Or just in general, use std::map, but it doesn't seem to like anything I give it. I am building using GCC 4.7.2 cross compiling to ARM through Sourcery CodeBench for ARM. Kind of at a loss. Regards, Michael Powell

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safe check if lockfree::queue is empty
by niXman 02 Apr '13

02 Apr '13

Hi, I read the docs about lockfree::queue::empty() and understang what this way is not safe in multithreaded program. The question is, how can I verify that the queue is empty? Will it be correct the following code? bool empty() { T *tmp = 0; if ( queue.pop(tmp) ) { queue.push(tmp); return false; } return true; } Thanks. -- Regards, niXman ___________________________________________________ Dual-target(32 & 64-bit) MinGW compilers for 32 and 64-bit Windows: http://sourceforge.net/projects/mingwbuilds/ ___________________________________________________ Another online IDE: http://liveworkspace.org/

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Good lock_guard<mytype> example
by Michael Powell 02 Apr '13

02 Apr '13

Hello, The pattern goes something like this: boost::lock_guard<mytype> guard(*this). However, compiler is asking for a lock or unlock. I don't know what this is, or what it should be. Thank you... Regards, Michael Powell

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Newbie Interprocess message_thread user
by John Davies 02 Apr '13

02 Apr '13

I'm new to Boost and new to Linux. But old to Windows. So I'm doing some initial development in Windows XP. I have two executables made in different projects. I planned on using a message_queue to communicate between the two applications. But sending a message from one app does not make it to the other. I can add and handle messages from one thread to another within the same application. SO I know I have things partially setup correctly. But now I'm at a complete loss. Should two exe files be able to communicate through Boost message_queues? Or am I misunderstanding the whole thing?

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