August 2011 - Boost-users - lists.preview.boost.org

How to detect thread kill?
by Samvel Khalatyan 02 Sep '11

02 Sep '11

Hi, There is a number of standard ways to interrupt thread from within an application with library tools. However, is there a way to detect if one of the running threads was killed with system tools and thread is not available any more? thanks, Samvel.

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[serialization] Export macro doesnt work
by Jari 02 Sep '11

02 Sep '11

Hi I was trying to use BOOST_CLASS_EXPORT for all my classes in order to save them but I always got unregistered class error. So I used oa.register_type<object>(); for the class that was causing the error and problem solved. But why doesnt the BOOST_CLASS_EXPORT macro work? Why I need to use oa.register_type<object>(); ? Im using Boost 1.46.1 Thanks

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complex matrix operations
by sairamesh raghuraman 02 Sep '11

02 Sep '11

Hello, I am looking for a C++ library that has routines for a variety of complex matrix decompositions (eigen, cholesky, singular value etc) and even complex matrix inverse, principal matrix logarthm of a complex matrix etc. And the matrices which I am talking are pretty huge..can go upto 1024 x 1024 x 32. I have already found a library that can do all of the above..used it..it works fine..but a disadvantage is that it cannot handle multidimensional arrays. Now the question is, does Boost C++ library have functions for the above? Looking forward to a reply and thanks in advance Ramesh

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[Program Options] notifiers for options with no value
by Dmitriy Matison 01 Sep '11

01 Sep '11

Hello, I'm wondering if there is a possibility to make program_options library to notify me automatically when option with no value is passed? As far as I understand this feature exists only for options with defined value_semantic. But this means I must permit passing a value for such options. Say, I make an option with zero_tokens() semantics so it can be passed without value and throw an error if some value was provided. Unfortunately, this doesn't solve the problem if you have positional options. In that case a positional option following a no-value option will be parsed as this option's value. I can't set notifier for options with no value? This is something not understandable. I even think of some patch to be added to the lib. Regards, Dmitriy.

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[bind] deduce arguments types
by Martin Häfner 01 Sep '11

01 Sep '11

Hi all, I have written a small grammar for command line parsing where function binders could be added as actors (callback) of a distinct option. The simple example below shows that the free function id(...) is called if the option -i is getting parsed and the bound member function is called when -j is given: bool id(int i) { return true; /* if id satisfies some preconditions, the parser will evaluate the result value */ } struct Id { void id(int i) { // the parser will not evaluate the 'void' result value } }; Id ident; bool rc = cmdline::Parser<SomePolicyA, SomePolicyB, SomePolicyC> ::parse(argc, argv, cmdline::Option<'i'>().doc("an integer identifier")) >> id <= cmdline::Option<'j'>().doc("another integer")) >> boost:bind(Id::id, &ident, _1) ); The problem now is that I want to deduce the result type of the given actor as well as the argument type. Retrieving the result type is manageable with boost binders but I have no idea how I could retrieve the argument type in order to do a proper conversion from char* to int without the usage of make_adaptable<> which breaks the elegance of the binder usage at this point. My self-written binder class exposes appropriate typedefs so the writer of the parser grammar does not have to cope with all that 'magic' template stuff, but I cannot get a working solution for boost::bind nor do I get a working solution with tr1 binders. Maybe anybody could help or at least could explain me why the boost classes do not define these simple typedefs? Regards, Martin

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[serialization] deserializing asynchronously serialized types
by Andrew Hundt 01 Sep '11

01 Sep '11

I have an unusual use case for boost.serialization, and I was wondering if it would be possible to adapt it to my needs: - I have a set of over 100 types, and instances of each are generated asynchronously then serialized to a file in that order. - The most interesting serialized data will be written just before the power is unexpectedly cut. - I need to load in and run on as much data as possible when reading the serialized data back, ignoring incomplete data at the end (due to a power cut). - The basic Boost serialization examples require you to know the type of the next piece of data to be loaded when reading. Since these types are generated asynchronously they are not known in advance. - I need to write the data out immediately when it arrives because of the power issue. - Files will be getting up to around 150GB in size for binary archives, so it can't be marshaled in memory, it needs to be written immediately even if it is redundant. Is there a way to read in that serialized file using the facilities provided in boost.serialization? I could also serialize an index or custom headers indicating the next type to appear, I would prefer to avoid doing so. One way of achieving some of these goals is writing one piece at a time using a binary archive to an fstream. But I don't know what aspects of my requirements will prove to be a problem. Thanks for your thoughts. Cheers! Andrew Hundt

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[asio] sync operations with timeout
by Gennady Proskurin 31 Aug '11

31 Aug '11

Hello. I write network library which offers blocking socket operations (connect, read, write, ...) with timeouts, using boost::asio asynchronous operations as implementation. It is actually some sort of wrapper around boost::asio. Implementation does something like this (read, for example): do_read() { timer.async_wait(&handle_timer) socket.async_read(..., handle_read); wait_for_all_handlers(); deal_with_ec(); } handle_timer() { socket.cancel(); } handle_read() { timer.cancel(); } I have one io_service for all the sockets/timers with one thread doing io_service::run(). Code is multithreaded, so many threads run that functions like do_read() simultaneously (for different sockets, of course). I have two questions: 1. How to wait for completion of all handlers? Currently I use shared_ptr with mutex+condvar (for each library call), it works fine, but seems to be too heavy-weight. 2. There is a chance (with small timeouts), that timer expires before async_read() is started, so sock.cancel() is no-op in handle_timer(), and timer will be disabled. Currently, I just ignore this. I can use another mutex (or strand) to protect from this, but it is also heavy-weight.

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Re: [Boost-users] Reg : Boost Error - any.hpp
by Vijay 31 Aug '11

31 Aug '11

Hi, Below is the snippet code, class Fcif; class FcifNode { public: FcifNode (const string& val): value (val) {}; FcifNode (const Fcif& fcif): value (fcif) {}; FcifNode (const FcifNode& node): value (node.value) {}; FcifNode& operator= (const string& val) { value = val; return *this; }; FcifNode& operator= (const Fcif& val) { value = val; return *this; }; FcifNode& operator= (const FcifNode& val) { value = val.value; return *this; }; bool isValue () const { return (value.type () == typeid (string)); }; bool isFcif () const; type_info const& type () const { return value.type (); }; string& getValue () const; Fcif& getFcif () const; string toString () const; protected: any value; }; class Fcif: public map<string,FcifNode> { public: Fcif () { }; Fcif (const Fcif& fcif): map<string,FcifNode> (fcif) { }; Fcif (const string& fcifString); string getValue (string const& name, bool required = true) const; bool checkValue (string const& name, string& value) const; bool setValue (string const& name, string const& value, bool escapeIt = true); void setValue (Fcif const& fcif); bool removeNode (string const& name, type_info const& type = typeid (void)); bool removeValue (string const& name) { return removeNode (name, typeid (string)); }; bool removeAggregate (string const& name) { return removeNode (name, typeid (Fcif)); }; bool setAggregate (string const& name, Fcif const& fcif); Fcif* getAggregate (string const& name) const { // auto-append '|' to name as needed return const_cast<Fcif*>(this)->addAggregate ( name + ((name.empty () || name[name.size()-1] == '|') ? "" : "|") , false); }; string toString () const; void parseFcif (string const& fcifString); private: Fcif* addAggregate (string const& name, bool create = true); Fcif parsePreFcif (string::const_iterator begin_pos, string::const_iterator& end_pos); string extractTag (string const& name) const { string::size_type tagpos = name.find_last_of ('|'); return name.substr (tagpos == string::npos ? 0 : tagpos + 1); }; string extractAgg (string const& name) const { string::size_type tagpos = name.find_last_of ('|'); return name.substr (0, tagpos == string::npos ? 0 : tagpos); }; }; Regards, Vijay Can you please post at least a self-consisting code snippet which allows to reproduce it... Otherwise I doubt someone will help you with this... Best Regards, Ovanes On Sun, Aug 28, 2011 at 7:57 AM, Vijay <v2k.sweet_at_[hidden]> wrote: > > > > Hi, > > We are using boost version 1.31.0 in our C++ code. Our OS is HP-UX 11.31 > Itanium. We use aCC compiler. While compiling my code, I'm getting the below > error. Can any one help me to fix this issue ? > > "/opt/app/q1app2c4/boost-1.31.0/boost/any.hpp", line 125: error #2070: > incomplete type is not allowed > ValueType held; > ^ > detected during: > instantiation of class > "boost::any::holder<ValueType> [with ValueType=Fcif]" > at > line 32 > instantiation of "boost::any::any(const ValueType &) [with > ValueType=Fcif]" at line 35 of > "/opt/app/q1app2c4/src/share/incl/Fcif.h" > > > > > Cheers, > Vijay....(V2K) > E-mail to : v2k.sweet_at_[hidden] > Catch me @ 9962003328, 7871181610 > Blackberry PIN : 259943F3 > "Life is just one grand sweet song, so start the music."

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Compiling version 1.43 of boost/graph with SunCC 5.8
by Renaud Kauffmann 30 Aug '11

30 Aug '11

#include <boost/graph/adjacency_list.hpp> using namespace boost; typedef adjacency_list <vecS, vecS, undirectedS> BoostGraph; typedef graph_traits < BoostGraph >::vertex_descriptor vertex_t; int main() { BoostGraph g; vertex_t v1 = add_vertex(g); vertex_t v2 = add_vertex(g); vertex_t v3 = add_vertex(g); return 0; } The above code doesn't seem to compile with Sun Studio 11, that is Sun C++ compiler 5.8 and boost 1.43 Here is the error: "/home/renaudk/boost/boost_1_43_0/boost/unordered/detail/table.hpp", line 38: Error: Could not find a match for boost::unordered_detail::hash_table<boost::unordered_detail::T>::find_iterator<boost::unordered_detail::hash_table<boost::unordered_detail::T>::Key, boost::unordered_detail::hash_table<boost::unordered_detail::T>::Pred>(bucket_ptr, const boost::unordered_detail::Key&, const boost::unordered_detail::Pred&) const. "/home/renaudk/boost/boost_1_43_0/boost/unordered/detail/table.hpp", line 38: Error: Too many args in template, from boost::unordered_detail::Pred on ignored. "/home/renaudk/boost/boost_1_43_0/boost/unordered/detail/table.hpp", line 595: Error: Could not find a match for boost::unordered_detail::hash_table<boost::unordered_detail::T>::find(const boost::unordered_detail::Key&, const boost::unordered_detail::Hash&, const boost::unordered_detail::Pred&) const. "/home/renaudk/boost/boost_1_43_0/boost/unordered/detail/table.hpp", line 595: Error: Too many args in template, from boost::unordered_detail::Hash on ignored. 4 Error(s) detected. I have tried some of the switch I found in the forums such as -library=stlport4 -features=tmplife -features=tmplrefstatic But no luck. Does anybody know the trick ? Thanks.

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[MSM] Is there an elegant way to get the outermost FSM?
by Gábor Márton 30 Aug '11

30 Aug '11

Hi, I am having a statemachine with a submachine. In the internal submachine I need to check if there is a flag active in the outer statemachine. Currently I solve this with a const pointer to the outermost FSM passed to the submachine's constructor: backEnd.set_states(msm::back::states_ << StOk(msm::back::states_ << StSlave(&backEnd))); StSlave is the internal submachine in which I need to check whether a flag in StOk is active or not. Then I check the flag activity status e.g in a guard of StSlave like this: struct GrdBladeUp { template<class EVT, class FSM, class SourceState, class TargetState> bool operator()(EVT const& event, FSM& fsm, SourceState&, TargetState&) { if(fsm.getOutermostFSM()->template is_flag_active<FlagBladeUp>()) { return true; } return false; } }; Is there an easier way to get somehow the parent fsm or the outermost fsm of a submachine? Thanks, Gabor

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