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Re: [Boost-users] noman javed: " problem in returning mpl::list"
by noman javed 28 Jul '08

28 Jul '08

I have already tried this and got the following error messeges example.cpp: In instantiation of ‘Poplist::apply<boost::mpl::list_c<int, 0l, 1l, 2l, 3l, 4l, 5l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l> >’: example.cpp:51: instantiated from here example.cpp:20: error: invalid use of undefined type ‘struct boost::mpl::pop_front<boost::mpl::list_c<int, 0l, 1l, 2l, 3l, 4l, 5l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l> >’ ../boost_1_35_0/boost/mpl/pop_front_fwd.hpp:20: error: declaration of ‘struct boost::mpl::pop_front<boost::mpl::list_c<int, 0l, 1l, 2l, 3l, 4l, 5l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l, 2147483647l> >’

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problem in returning mpl::list
by noman javed 28 Jul '08

28 Jul '08

Hi I am trying to write a meta-function class, receiving a list as argument and returning the reduced list by poping one element from the front. Here is my code struct Poplist { template<class seq> struct apply { typedef pop_front<seq>::type res; static const int value = size<seq>::value; }; }; int main() { typedef list_c<int,0,1,2,3,4,5> numbers; cout<<Poplist::apply<numbers>::value<<endl; } And I got the following error example.cpp:20: error: type ‘boost::mpl::pop_front<seq>’ is not derived from type ‘Poplist::apply<seq>’ example.cpp:20: error: expected ‘;’ before ‘res’ Can someone please rectify my code Thanks in advance

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Is there a something in boost to facilitate binary buffer transformations into typed data structures/classes?
by Graham Reitz 28 Jul '08

28 Jul '08

I didn't see anything, but I may have missed something. Problem: Binary data is stored in a char buffer from a proprietary device: char* buffer = new char[6]; Data in buffer: [byte 1][byte 2][byte 3][byte 4][byte 5][byte 6] [---16 bit uint--][------------32 bit uint-------------] ...would like to convert to this in a C++'ish style using a boost facility if it exists: (or consider directing me somewhere else if it doesn't) struct // or class { boost::uint16_t first; boost::uint32_t second; } data; I would like to avoid a C-style way of doing this. This seems like something that would have been solved many times. thanks, graham

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Re: [Boost-users] XML library?
by Tan, Tom (Shanghai) 28 Jul '08

28 Jul '08

> On Sat, Jul 26, 2008 at 03:44:54PM +0200, Michiel Helvensteijn wrote: > > In the meantime, can anyone recommend another open source C++ XML library I > can use (with DOM parser)? > >http://xerces.apache.org/xerces-c/ POCO: http://www.appinf.com/poco/info/index.html

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German language Boost tutorial available
by Ruediger Berlich 27 Jul '08

27 Jul '08

Hi there, by the beginning of this year I have written a three-part tutorial on using Boost for a German IT publication ("iX"). The magazine has now made the articles publicly available on their web page, under the following URLs: http://www.heise.de/ix/artikel/2007/12/134/ http://www.heise.de/ix/artikel/2008/01/144/ http://www.heise.de/ix/artikel/2008/02/138/ Note that the articles still refer to Boost 1.33.x/1.34, so that a few things are not applicable anymore to the upcoming version 1.36 . Hopefully they are nevertheless usefull for a few people. Best Regards, Ruediger /*************************************************************************/ The Steinbuch Centre for Computing of Karlsruhe Institute of Technology (the Cooperation of Forschungszentrum Karlsruhe GmbH and Universitaet Karlsruhe TH) will run its annual GridKa School from September 8th to 12th, 2008. Please find further information at http://www.fzk.de/gks08 . /*************************************************************************/

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[Boost.thread] Exception handling strategy ?
by Ruediger Berlich 27 Jul '08

27 Jul '08

Hi there, is there a recommended strategy for exception (or more generally error-)handling with Boost.thread ? From what I can see it is not safe to throw an exception from within a thread, as it is not sure who catches it (or whether it gets caught at all). Best, Ruediger

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[ASIO] Correct way to reconnect a failed TCP connection
by Simon Pickles 27 Jul '08

27 Jul '08

Hello, I am having a little trouble getting my boost::ASIO TCP client to actually re-attempt a connected if the first attempt failed. With my server offline, the call to async_connect correctly times out. When I try the async_connect call a second time, it doesn't time out. I am running my io_service listener in a boost thread, and am not changing this between async_connect calls. However, my debugger (MSVC2005, boost 1.35) does show a thread exit at this time. I don't think its the relevant thread (at the second call to connect there is an extra thread running (the io_service I guess). Here's my two relevant files. Thanks very much for any pointers Simon // Network.cpp //-------------------- // CNetwork::Connect // ........ m_client = boost::shared_ptr<CASIOClient>( new CASIOClient( m_log, m_initXML, m_IO, this ) ); try { tcp::resolver resolver(*(m_IO.get())); tcp::resolver::query query( m_serverHost.c_str(), m_serverPort.c_str() ); tcp::resolver::iterator iterator = resolver.resolve(query); m_client->Connect(iterator); m_log->NET( "Looking for Server at %s:%s\n", m_serverHost.c_str(), m_serverPort.c_str() ); } catch (boost::system::error_code& e) { m_log->NET("%s\n", e.message().c_str() ); m_log->NET("Server not found?\n"); return -1; } catch (std::exception& e) { m_log->NET("Exception %s\n", e.what() ); return false; } // start the io service to listen for async ops if ( !m_listener ) m_listener = boost::shared_ptr<boost::thread>( new boost::thread(boost::bind(&boost::asio::io_service::run, m_IO.get()) ) ); //------------------------------------- // CASIOClient.cpp CASIOClient::CASIOClient( boost::shared_ptr<ILogInterface> log, boost::shared_ptr<IXMLInterface> xml, boost::shared_ptr<boost::asio::io_service> io, CNetwork* network ): m_IO(io), m_socket(*(io.get())), m_network(network) { m_log = log; m_initXML = xml; } void CASIOClient::Connect( tcp::resolver::iterator endpoint_iterator ) { tcp::endpoint endpoint = *endpoint_iterator; m_socket.async_connect( endpoint, boost::bind( &CASIOClient::HandleConnect, this, boost::asio::placeholders::error, ++endpoint_iterator)); m_connectionState = NETWORK_DISCONNECTED; } void CASIOClient::Close() { m_log->NET("Starting Close...\n"); m_IO->post(boost::bind(&CASIOClient::DoClose, this)); } ////////////////////////////////////////// void CASIOClient::HandleConnect( const boost::system::error_code& error, tcp::resolver::iterator endpoint_iterator) { if (!error) { m_log->NET("Connected: %s\n", error.message().c_str()); m_connectionState = NETWORK_CONNECTED; boost::asio::async_read_until( m_socket, m_rx, '@', // termination char boost::bind( &CASIOClient::HandleReadUntil, this, boost::asio::placeholders::error)); } else if (endpoint_iterator != tcp::resolver::iterator()) { m_log->NET("Connection unsuccessful: %s\n", error.message().c_str()); m_log->NET("Retrying\n"); tcp::endpoint endpoint = *endpoint_iterator; m_socket.async_connect( endpoint, boost::bind( &CASIOClient::HandleConnect, this, boost::asio::placeholders::error, ++endpoint_iterator)); } else { m_log->NET("Connect Error: %s\n", error.message().c_str()); DoClose(); } } void CASIOClient::HandleReadUntil(const boost::system::error_code& error) { if (!error) { std::istreambuf_iterator<char> iter(&m_rx); std::istreambuf_iterator<char> end; std::string read(iter, end); std::string clipMsg; while (read.length()) { int n = read.find("@"); clipMsg = read.substr( 0, n ); m_log->NET( "Message received: %s\n", clipMsg.c_str() ); m_network->QueueReceivedMessage( clipMsg ); read = read.substr( n+1, read.length()-n-1 ); } // start listening again boost::asio::async_read_until( m_socket, m_rx, '@', boost::bind( &CASIOClient::HandleReadUntil, this, boost::asio::placeholders::error)); } else { m_log->NET( "ReadUntil Error: %s\n", error.message().c_str() ); DoClose(); } } void CASIOClient::DoClose() { m_log->NET( "Closing ASIO\n" ); m_socket.close(); m_connectionState = NETWORK_FAILED; }

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[boost-users][StateChart] failure during termination
by Igor R 27 Jul '08

27 Jul '08

Hello, When trying to terminate an asynchronous_state_machine I get the error message: "Expression: list iterator not decrementable". This occures in state_machine::terminate_impl( state_base_type & theState, bool performFullExit ) in the line: else if ( currentStates_.begin() == --currentStatesEnd_ ), when trying to perform --currentStatesEnd_, as currentStatesEnd_== 0xcdcdcdcd (i.e. uninitialized). theState == outermost state of the machine. I believe the problem is actually somewhere in my own code, so my question is what it could be, according to the above symptom? I request the termination in the following way: struct ServerImpl { //.... shared_ptr<state_chart::fifo_scheduler<> > sessionScheduler_; state_chart::fifo_scheduler<>::processor_handle sessionProcessor_; ~ServerImpl() { // the scheduler resides in some pool, so it continues living after ~ServerImpl sessionScheduler_->terminate_processor(sessionProcessor_); } Thank you, Igor'.

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[Graph] Disjoint Sets and Incremental Components with VertexList=listS
by Pedro Teixeira 27 Jul '08

27 Jul '08

Hi all, I am quite new to boost and would appreciate a hint on the following matter. My doubt is related to what exactly does the API expects in terms of a ReadWriteProperty and currently I am not amble to figure it out how to instantiate a disjoint_set for a graph of type adjacency_list <setS, listS, undirectedS>. The example (to a vecS graph) shows: std::vector<size_type> rank(num_vertices(G)); std::vector<Vertex> parent(num_vertices(G)); typedef size_type* Rank; typedef Vertex* Parent; disjoint_sets<Rank, Parent> ds(&rank[0], &parent[0]); I just spent some time trying different combinations of map<Vertex, size_type> and map<Vertex, Vertex> but it does not work. Also tried boost::property_map<Graph, boost::vertex_predecessor_t>::type for parent, but it didn't work either. Can anyone shed some light? thanks! Pedro

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How do I push_back classes that disallow copy construction?
by Kevin Jenkins 26 Jul '08

26 Jul '08

How do I do this? Is there a way to make the boost::fusion vector hold references instead of copies? Or hold pointers? class DoNotCopyConstructMe { public: DoNotCopyConstructMe() {} private: DoNotCopyConstructMe(const DoNotCopyConstructMe &ref) {} }; DoNotCopyConstructMe var1,var2,var3,var4; boost::fusion::push_back(boost::fusion::make_vector(var1,var2,var3),var4); Error 1 error C2248: 'DoNotCopyConstructMe::DoNotCopyConstructMe' : cannot access private member declared in class 'DoNotCopyConstructMe' c:\boost_1_35_0\boost\fusion\view\single_view\single_view.hpp 38

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