June 2011 - Boost-users - lists.boost.org

[filesystem]
by Ford Sleeman 15 Jun '11

15 Jun '11

Hi everybody, I am trying to use the Boost filesystem library and ran into a strange problem. When I include the library in a project (automake or standard Makefile) I can link everything and the resulting program runs fine. I get errors like this for even including the <boost/filesystem.hpp> file in a second source or header file: [my path]/boost/exception/exception.hpp:179: error: expected identifier before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:179: error: expected `>' before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:180: error: expected unqualified-id before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:182: error: expected identifier before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:182: error: expected `>' before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:183: error: expected unqualified-id before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:185: error: expected identifier before numeric constant I could not find any examples of linking multiple files in a project with the library, does such exist? Is there something special to include the headers in this situation? If I comment out the #include and any references to the boost::filesystem functions in the second source file the program will compile correctly. Thanks, Ford Sleeman NOTE: The information contained in this message may be privileged and confidential and protected from disclosure. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by replying to the message and deleting it from your computer. -------------------------------------- VCU Health System http://www.vcuhealth.org

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[math/distributions] Problem using inv-chi**2 and quantiles
by Paul Johnson 15 Jun '11

15 Jun '11

I'm trying to duplicate Excel's CHIINV to calculate confidence limits for an observed number of events. I think I'm nearly there, largely as a result of trial and error, but the boost results still significantly differ from the Excel results, so I've presumably messed up somewhere. Any advice will be *greatly* appreciated. The Excel formulas I'm using are: lo limit = CHIINV((1+$C$3)/2, 2*B6)/2 hi limit = CHIINV((1-$C$3)/2, 2*(B6+1))/2 where $C$3 is the confidence level required (95%), and B6 is the number of events observed. In Excel, 'CHIINV' is documented as: > CHIINV(probability,degrees_freedom) > Probability is a probability associated with the chi-squared distribution. > Degrees_freedom is the number of degrees of freedom. For 17 events, for example, Excel is producing limits of [9.90, 27.22]. I've attached my complete boost test program below, which I hope does the same thing, but there was a large amount of guesswork here. This program produces results of [10.67, 25.98] for 17 events. Can anyone tell me what I'm doing wrong? Thanks - Paul

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[msm] EUML submachine without macro
by rayg 15 Jun '11

15 Jun '11

Hi, I'm trying to define a submachine without the BOOST_MSM_EUML_DECLARE_STATE_MACHINE macro (the "old" way - like in http://www.boost.org/doc/libs/1_46_0/libs/msm/doc/HTML/examples/SimpleTutor…) The "main" machine works as expected. However, the submachine doesn't kick in at all (the system asserts in default no-transition handler). Any ideas? Ray ------------ #include <boost/msm/front/state_machine_def.hpp> #include <boost/msm/front/euml/euml.hpp> #include <boost/msm/back/state_machine.hpp> using namespace std; using namespace boost::msm::front::euml; namespace msm = boost::msm; //#define WITH_MACROS //************ //* Events //************ BOOST_MSM_EUML_EVENT(play) BOOST_MSM_EUML_EVENT(toggle) //************* //* Submachine //************* #ifdef WITH_MACROS //************************ //* This works fine //************************ BOOST_MSM_EUML_ACTION(Song1_Entry) { template <class Event,class FSM,class STATE> void operator()(Event const&,FSM&,STATE& ) { // Called as expected std::cout << "entering: Song1" << std::endl; } }; BOOST_MSM_EUML_STATE((Song1_Entry), Song1) BOOST_MSM_EUML_STATE((), Song2) BOOST_MSM_EUML_TRANSITION_TABLE(( Song2 == Song1 + toggle, Song1 == Song2 + toggle ), sub_transition_table) BOOST_MSM_EUML_DECLARE_STATE_MACHINE((sub_transition_table, init_ << Song1), _Playing) #else //************************ //* Doesn't work //************************ struct Song1_impl : public msm::front::state<> , public msm::front::euml::euml_state<Song1_impl> { template <typename EVENT, typename FSM> void on_entry(EVENT const&, FSM& fsm) { // Not called std::cout << "entering: Song1" << std::endl; } }; struct Song2_impl : public msm::front::state<> , public msm::front::euml::euml_state<Song2_impl> { }; Song1_impl const Song1; Song2_impl const Song2; struct _Playing : public msm::front::state_machine_def< _Playing > { // Initial state typedef Song1_impl initial_state; BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE(( Song2 == Song1 + toggle, Song1 == Song2 + toggle ), sub_transition_table) }; #endif // Pick a back-end typedef msm::back::state_machine<_Playing> Playing_impl; Playing_impl const Playing; //********************************** //* Main machine //********************************** struct Empty_impl : public msm::front::state<> , public msm::front::euml::euml_state<Empty_impl> { }; Empty_impl const Empty; struct _Player : public msm::front::state_machine_def< _Player > { // Initial state typedef Empty_impl initial_state; BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE(( Playing == Empty + play ), transition_table) }; // Pick a back-end typedef msm::back::state_machine<_Player> player; int main(int argc, char* argv[]) { player p; p.start(); p.process_event( play ); return 0; } -- View this message in context: http://boost.2283326.n4.nabble.com/msm-EUML-submachine-without-macro-tp3598… Sent from the Boost - Users mailing list archive at Nabble.com.

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reference_wrapper 101
by Robert Jones 15 Jun '11

15 Jun '11

I thought understood what boost::reference_wrapper was all about, and in the context of, say Boost.Bind, it seems pretty clear. But why would you define a function to RETURN a reference_wrapper? eg template <class T> struct X { std::pair<boost::reference_wrapper<T>, unsigned> getSomething(....) const; }; I suspect I'm having a 'doh' moment here! Thx, - Rob.

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Re: [Boost-users] [statechart] Is it possible to have nested (sub)states in an asynchronous state machine?
by Igor R 15 Jun '11

15 Jun '11

> Thanks for the recommendation. The problem turned out to be indeed with > forward declarations. I wish the compilation errors were somewhat more > informative, so that I could find the root cause of the problem easily. I don't know what compiler you used and what your real code looked like, but when I tried to compile some portions of your sample code with VC10, I got a lot of "use of undefined type" errors.

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Re: [Boost-users] [statechart] Is it possible to have nested (sub)states in an asynchronous state machine?
by Gurcan Gulesir 15 Jun '11

15 Jun '11

Thanks for the recommendation. The problem turned out to be indeed with forward declarations. I wish the compilation errors were somewhat more informative, so that I could find the root cause of the problem easily. -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Igor R Sent: donderdag 9 juni 2011 18:33 To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [statechart] Is it possible to have nested (sub)states in an asynchronous state machine? > Putting everything into one file, surprisingly for me, solved my problem of > not being able to nest a sub-state under a super state. Now I need to figure > out why the previous implementation (i.e., the one distributed over multiple > files) does not compile. I guess you try to use undefined (forward-declared) types in contexts where they cannot be used. _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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asio ssl peer authentication, check which certificate is really authenticated
by Lloyd 15 Jun '11

15 Jun '11

Hi, I have gone through the asio ssl client and server sample and modified. The modification I have done is, added one more certificate to the client by using "ctx.load_verify_file("another_cert.pem");" Now I have two server certificates loaded for server authentication. These are self signed certificate. But in client is there any way to know which server is authenticated? In real case we will be using this for client-authentication, to know what kind of client is connected to the server. We have two types of client, and one client has only restricted privileges. Thanks, Lloyd

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Boost filesystem v3 with Qt.
by Surya Kiran Gullapalli 15 Jun '11

15 Jun '11

Hello, Sorry for cross-posting. I'm facing an issue with Qt (4.7.2, installed from Qt installer) with Boost.Filesystem v3 (1.46.1) on VS2008. I'm facing linker errors with QString::toStdWString when /Zc:wchar_t is set like this: unresolved external symbol "__declspec(dllimport) public: class std::basic_string<wchar_t,struct std::char_traits<wchar_t>,class std::allocator<wchar_t> > __thiscall QString::toStdWString(void)const " (__imp_?toStdWString@QString@@QBE?AV?$basic_string@_WU?$char_traits@_W@std@@V?$allocator@_W@2@@std@@XZ) referenced in function "private: void __thiscall DirView::readDirectory(class QModelIndex const &)" (?readDirectory@DirView@@AAEXABVQModelIndex@@@Z) and linker errors with std::codecvt when /Zc:wchar_t- is set like this: unresolved external symbol "__declspec(dllimport) public: static class std::codecvt<unsigned short,char,int> const & __cdecl boost::filesystem3::path::codecvt(void)" (__imp_?codecvt@path@filesystem3@boost@@SAABV?$codecvt@GDH@std@@XZ) referenced in function "public: __thiscall boost::filesystem3::path::path<class std::basic_string<unsigned short,struct std::char_traits<unsigned short>,class std::allocator<unsigned short> > >(class std::basic_string<unsigned short,struct std::char_traits<unsigned short>,class std::allocator<unsigned short> > const &,void *)" (??$?0V?$basic_string@GU?$char_traits@G@std@@V?$allocator@G@2@@std@@@path@filesystem3@boost@@QAE@ABV?$basic_string@GU?$char_traits@G@std@@V?$allocator@G@2@@std@@PAX@Z) How can i use Qt with boost filesystem ? Thanks in advance, Surya

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fast_pool_allocator question
by steviekm3 14 Jun '11

14 Jun '11

I was wondering if fast_pool_allocator will speed something up. I have a funtion say g which looks like: void g( Params p ) { std::map<double,Foo> m; for( int i = 0; i < 100000; ++it ) { m.insert( ... ) } } g gets called from about 100 different threads running on 16 processor machine. All the processors are not being used near full capacity. I did some analysis and find that most of the time one thread is in malloc system call and other threads are blocking on it. ( I guess malloc only allows serial access a certain points ). Would a fast_pool_allocator speed this up. Could I pre-allocate the memory needed using a fast_pool_allocator ? I don't want the pool to return memory to the system. Just to reuse memory that is no longer needed ( reuse memory that m has used after m goes out of scope ). -- View this message in context: http://boost.2283326.n4.nabble.com/fast-pool-allocator-question-tp3596247p3… Sent from the Boost - Users mailing list archive at Nabble.com.

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Boost::Asio crashes all the time when starting multiple connections
by Andi Clemens 14 Jun '11

14 Jun '11

Hi, I have started to write a ProxyServer that analyzes TDS-packages sent from the Microsoft SQLServer Management Studio to a MS SQLServer. It seems to work fine for one or two connections, but if more connections are openend, boost suddenly crashes, mostly in the bind-template.hpp: template<class A1, class A2> result_type operator()(A1 const & a1, A2 const & a2) { list2<A1 const &, A2 const &> a(a1, a2); CRASH ===> BOOST_BIND_RETURN l_(type<result_type>(), f_, a, 0); } I have modified the code from the examples page: http://www.boost.org/doc/libs/1_46_1/doc/html/boost_asio/example/echo/async… I only added a second socket in the session class for handling the connection to the SQLServer. When I start SSMS and click on "New query", I can see two additional connections being opened, and then the program crashes. I have posted the source code here: session.h : http://pastebin.com/eC5fn7U8 session.cpp : http://pastebin.com/LDnQqCNr server.h: http://pastebin.com/1fDJU6sx server.cpp: http://pastebin.com/seMAVx4D ProxyServer.cpp: http://pastebin.com/8S7YfE8L Am I doing something wrong? Maybe the code isn't threadsafe? I'm new to boost::asio and I might have missed an important point here. Maybe I need more than one io_service object? Andi -- Using Opera's revolutionary email client: http://www.opera.com/mail/

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