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odeint feedback request
by Karsten Ahnert 25 Oct '11

25 Oct '11

Dear community, odeint is a library for solving ordinary differential equations and has been discussed several times on this list. After successfully fulfilling the GSOC 2011 we continued working on odeint and we published two papers which are available at the arxiv: http://arxiv.org/abs/1110.3397 http://arxiv.org/abs/1110.3233 We would like to request feedback and/or comments on the implementation and the current status of odeint. The library and the documentation are available at the github: https://github.com/headmyshoulder/odeint-v2 http://headmyshoulder.github.com/odeint-v2/doc/index.html Thank you, Mario and Karsten

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[regex] /g
by Andrey Moshbear 25 Oct '11

25 Oct '11

I have a few questions regarding implementing /g when using boost.regex. Firstly, is the iterator-pair form of match equivalent to /g? I.e. { sregex_iterator m1(str.begin(), str.end(), regex); sregex_iterator m2; for (; m1 != m2; ++m1) { // do something with *m1 } } Secondly, does regex_replace() loop internally in a /g fashion? 001100 Andrey "m05hbear" Vul 010010 011110 andrey at moshbear dot net 100001 andrey dot vul at gmail 101101 110011

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[fusion] push_back / pop_back
by Daniel Bradburn 25 Oct '11

25 Oct '11

Hi, I am trying to do the following: #include <string>#include <boost/fusion/tuple.hpp>#include <boost/fusion/include/push_back.hpp>#include <boost/fusion/include/pop_back.hpp> int main(int argc, char* argv[]) { typedef boost::fusion::tuple<int> T1; typedef boost::fusion::result_of::push_back<const T1, std::string>::type T2; T1 a(0); T2 b(boost::fusion::push_back(a, std::string(""))); boost::fusion::get<0>(); T1 c(boost::fusion::pop_back(b)); return 0; } However I get the following compilation errors: error C4430: missing type specifier - int assumed. Note: C++ does not support default-int error C2868: 'boost::lazy_disable_if_c<B,T>::type' : illegal syntax for using-declaration; expected qualified-name error C2602: 'boost::lazy_disable_if_c<B,T>::type' is not a member of a base class of 'boost::lazy_disable_if_c<B,T>' error C2504: 'boost::fusion::extension::at_impl<Tag>::apply<Sequence,N>' : base class undefined error C2504: 'boost::fusion::extension::at_impl<Tag>::apply<Sequence,N>' : base class undefined error C2146: syntax error : missing ';' before identifier 'type' error C2039: 'type' : is not a member of 'boost::fusion::result_of::at_c<Sequence,N>' error C2664: 'boost::fusion::tuple<T0>::tuple(const boost::fusion::tuple<T0> &)' : cannot convert parameter 1 from 'boost::fusion::iterator_range' to 'const boost::fusion::tuple<T0> &' error C2146: syntax error : missing ',' before identifier 'type' error C2065: 'type' : undeclared identifier error C2039: 'type' : is not a member of 'boost::fusion::result_of::prior<Iterator>' Having read the topic here : http://lists.boost.org/Archives/boost/2011/08/184624.php it looks like this is partly due to a bug in the pop_back implementation. Is there a fix for this? However I would like to know if it is also possible to use boost::fusion::get on the result of push_back? Best regards Daniel Bradburn

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throw and catch exception
by Christer Borgqvist 25 Oct '11

25 Oct '11

I have a code like this when execute the IdHTTPServDataEMVObj.Exequte(); it will throw a std::runtime_error if running one thread all is fine, the catch is excequted, but if running two threads then the application crash. What is the problem, have i miss something appreciate any help. huvcbo.. void server(boost::asio::io_service& io_service, short port) { tcp::acceptor a(io_service, tcp::endpoint(tcp::v4(), port)); for (;;) { socket_ptr sock(new tcp::socket(io_service)); a.accept(*sock); boost::thread t(boost::bind(socketclientEMVthread, sock, logFunc, mygetFunc, mybackFunc, statusUpdateFunc)); } } the client thread void socketclientEMVthread( socket_ptr sock) { cout << "connect on port " << sock->remote_endpoint().port() << endl; for (;;) { char data[max_length]; boost::system::error_code error; size_t length = sock->read_some(boost::asio::buffer(data), error); if (error == boost::asio::error::eof) break; // Connection closed cleanly by peer. else if (error) throw boost::system::system_error(error); // Some other error. std::string trans_in(data), trans_out; CIdHTTPServDataEMVObj IdHTTPServDataEMVObj(trans_in); try { // this is thrown IdHTTPServDataEMVObj.Exequte(); if ( IdHTTPServDataEMVObj.txBufferlen > 0 && IdHTTPServDataEMVObj.txBufferlen != std::string::npos) { trans_out = IdHTTPServDataEMVObj.txBuffer; } else { trans_out = trans_in; } } catch(trans_error &te) { trans_out = te.what(); boost::asio::write(*sock, boost::asio::buffer(trans_out, trans_out.size())); break; } boost::asio::write(*sock, boost::asio::buffer(trans_out, trans_out.size())); break; } }

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[date time] How to get "10" and not "Oct"
by Ken Murphy 24 Oct '11

24 Oct '11

I have the following code: std::string db_time() { typedef boost::posix_time::ptime TimeT; TimeT ct = boost::posix_time::microsec_clock::local_time(); std::stringstream ss; boost::local_time::local_time_facet* output_facet = new boost::local_time::local_time_facet("%Y-%m-%d %h:%m:%s"); ss.imbue(std::locale(std::locale::classic(), output_facet)); ss << ct; return ss.str(); } Currently, the following string is returned: 2011-Oct-24 12:43:05.476990 How do I get the month as "10" and not as "Oct"? Ken Murphy

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asio. documentation errors.
by niXman 24 Oct '11

24 Oct '11

Hi list! In the documentation for upd::socket::bind(): http://www.boost.org/doc/libs/1_47_0/doc/html/boost_asio/reference/basic_da… examples are shown from the tcp::socket::bind() Thanks. niXman.

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Problems with (de)serialization from/through pointer to base class
by Rafael Arco Arredondo 24 Oct '11

24 Oct '11

Hello: I am encountering problems with boost::serialization, particularly when objects are sent with boost::mpi and contain pointers to a base class. I am getting segmentation faults, but not always, only when the transmitted objects exceed a particular size. I have two abstract classes, A and B, two instantiable classes, D and E, and a fifth class C, which is the class eventually serialized and contains one pointer to an object of class A and another to an object of class B. In the example attached, when n (which determines the size of E objects) is 1000, everything works fine. If, for instance, n=2000, the segmentation fault appears when the object is deserialized after calling comm.recv. The output for this last case is also attached in file output.log. I am also using boost::shared_ptr as well to wrap class C objects, but the error is also thrown when no shared pointers are used. When types and object sizes are known a priori there are no problems, but I would need something more general and dynamic right now. It is possible to do this, isn't it? Any ideas of what is happening? Am I doing something wrong? Did I miss something in the documentation? Is there any size limitation for serializing/deserializing objects? I imagine MPI_Unpack, which appears in the stack trace, is restricted by the size of the input buffer, indicated by an int, but I believe this is not the problem here. Is it perhaps a bug? Any help or comments will be appreciated. Thank you in advance, Rafa

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[optional] Working around gcc 4.6 bug which produces error "‘*((void*)& aNewItem +8)’ may be used uninitialized in this function"
by Rob Desbois 24 Oct '11

24 Oct '11

I've just begun having issues with some use of boost::optional producing the error shown in the subject. This is a gcc bug, filed at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47679 The corresponding downstream bug for RedHat/Fedora is at https://bugzilla.redhat.com/show_bug.cgi?id=676361 and has a code listing to reproduce. Sending this partially as an FYI, and also to ask if anyone has any workaround? Altering client code to construct with boost::none or a false condition, then assigning a value if required, still yields the error on the assign operation. My current workaround is to initialize the optional<T> in question with a dummy T instance, then call reset() with no params if I want an 'uninitialized' optional. It looks rather bizarre, but if it must be then it must be. -- Rob Desbois Eml: rob.desbois(a)gmail.com Blog: http://theotherbranch.wordpress.com/

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[regex] Grouping behaviour
by U.Mutlu 24 Oct '11

24 Oct '11

Hi, I need to split a regex pattern into two groups like from this blafoo to (bla)(foo) But the second variant matches also input like this one: blaABCfoo There is no .* between the groups, so I wonder why it still matches. How to fix this?

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Re: [Boost-users] [locale] IOStream encoding conversions?
by Artyom Beilis 24 Oct '11

24 Oct '11

> Currently I'm messing about with Boost.Locale, I'm intending to use it > for my project, but I don't know how to do something along the lines of > specifying the external encoding (usually the user's locale, en_US.UTF-8 > in my case), and the internal coding of my program (UTF-16), > to have input and output converted, possibly using a codecvt. A possible example > would be translating UTF-16-≥POSIX UTF-8 paths, or UTF-8-≥Windows UTF-16 > paths. I assume you use Windows and wide characters. It is enough to imbue the locale to the output **wide** stream and write to it. boost::locale::generator gen; // stdout std::wcout.imbue(gen("")); std::wcout << L"שלום" << std::endl; // UTF-8 file I/O std::wfstream stream; stream.imbue(gen("")); stream.open(name,std::wfstream::out); stream << L"שלום" << std::endl; Would actually output the text in narrow encoding. Also there is an example how to create custom wide streams that would convert wide to narrow encoding http://svn.boost.org/svn/boost/trunk/libs/locale/doc/html/charset_handling.… Also for converting things like path UTF-8/UTF-16 you can use utf_to_utf functions that work just on chunks of text. http://svn.boost.org/svn/boost/trunk/libs/locale/doc/html/group__codepage.h… Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.sf.net/ CppDB - C++ SQL Connectivity: http://cppcms.sf.net/sql/cppdb/

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