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boost::result_of and pure virtual functor leads to compile error
by oswin krause 30 Apr '13

30 Apr '13

Hi list, I am necountering an error when trying to use boost::result_of on a pure virtual base class. minimal example: struct Test{ typedef int result_type; virtual int operator()(int)=0; }; typedef boost::result_of<Test(int)>::type type; leads with gcc 4.8 (and with every compiler i know of) to the following output: Error: »type name« declared as function returning an abstract class type typedef boost::result_of<Test(int)>::type type; (actually in the original code where this showed up, gcc compiles it just fine only every other compiler fails, but in this very simple example, even gcc get's the message...) Any chance to use result_of in this setting? I clearly can't use the function call syntax here, which is a little bit annoying. Greetings, Oswin

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[Graph] Difference between astar_search and astar_search_tree
by Luis Torres 29 Apr '13

29 Apr '13

I didn't find the A* documentation very clear on this: when should one use astar_search, and when should one use astar_search_tree? Does the distinction have to do with whether the given heuristic is consistent? Thanks, Luis

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boost::serialization throwing “input stream error” on base class ptr XML serialization
by jvetter 26 Apr '13

26 Apr '13

Hello, This seems straight forward to me, but yet I'm stilling getting a input stream error and I don't understand why. The weird part about it is if I un-comment the serialization of the base class in my example it works, otherwise it does not. Here is the code: struct A { virtual ~A() {}; int i1 = 10; friend class boost::serialization::access; template <class Archive> void serialize(Archive& ar, const unsigned int version) { ar & make_nvp("int", i1); } }; struct B : A { virtual ~B() {}; float f1 = 5.0F friend class boost::serialization::access; template <class Archive> void serialize(Archive& ar, const unsigned int version) { ar & boost::serialization::base_object<A>(*this); ar & make_nvp("float", f1); } }; struct C : A { virtual ~C() {}; long l1 = 24; friend class boost::serialization::access; template <class Archive> void serialize(Archive& ar, const unsigned int version) { ar & boost::serialization::base_object<A>(*this); ar & make_nvp("long", l1); } }; //Why do these need to be wrappers?? namespace boost { namespace serialization { template<> struct is_wrapper<A*> : mpl::true_ {}; template<> struct is_wrapper<A> : mpl::true_ {}; template<> struct is_wrapper<const A> : mpl::true_ {}; } } BOOST_SERIALIZATION_ASSUME_ABSTRACT(A); BOOST_CLASS_EXPORT(B) BOOST_CLASS_EXPORT(C) int main(int argc, char** argv) { //A* a = new A(); A* b = new B(); A* c = new C(); //A* a1 = nullptr; A* a2 = nullptr; A* a3 = nullptr; ostringstream ostream; xml_oarchive oarchive(ostream); oarchive /*<< BOOST_SERIALIZATION_NVP(a)*/ << BOOST_SERIALIZATION_NVP(b) << BOOST_SERIALIZATION_NVP(c); istringstream istream(ostream.str()); xml_iarchive iarchive(istream); iarchive /*>> BOOST_SERIALIZATION_NVP(a1)*/ >> BOOST_SERIALIZATION_NVP(a2) >> BOOST_SERIALIZATION_NVP(a3); //delete a; delete b; delete c; //delete a1; delete a2; delete a3; } It's worth mentioning that this is with Boost 1.53 and GCC 4.8.0 w/ --std=c++11. The same code works fine in both cases worth the text and binary archives. I have tried changing the nvp's in the main to have the same key and in the input case no key, but I get the same error. Am I doing something wrong or is there an issue with the xml archive? Thanks, Jaime

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Re: [Boost-users] Boost, MinGW and SjLj
by Archie Campbell 26 Apr '13

26 Apr '13

2013/4/26 Archie Campbell: > Hi, > > I have compiled boost_1_53_0 using bjam on windows with MinGW (gcc-4.6.3). > > I am using CodeBlocks for IDE and have successfully linked against Qt5. > > Attempting to link against libboost_serialization produces undefined > references > to things like sjlj_unwind and archive_exception. > > What's going wrong? Do I need to flag the compiler to change exception > strategy? > > Thanks in advance. > > Archie This occurs when one of the libraries compiled using the not SJLJ build of MinGW. (dwarf, for example) I fixed it, eventually, after much messing around with PATH. The strawberry perl c compiler, an irrelevant sjlj build, had snuck in somewhere along the line and had been picked up by bjam. As it turns out, I had to download TDM-GCC-4.7.1, mingw & sjlj to build against Qt5. Boost, and my engine's code were happy to use Mingw 4.6.2, dwarf build, but once the libraries had compiled alright, complained badly during my code's compilation when I tried gcc 4.7.1. Spent the rest of the day fixing up windows IO and all those enchanting little differences between OS designs :P I now have at least four MinGW toolchains but I'm not looking for trouble. Archie

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[log] Compile error with gcc 4.4.6
by Jason 26 Apr '13

26 Apr '13

I'm trying to compile the Boost trunk with gcc 4.4.6, which is the version currently packaged for the RHEL/CentOS 6.x series. In doing so, I'm running into a compiler error that was documented previously on the SourceForge forum for Boost.Log: http://sourceforge.net/projects/boost-log/forums/forum/710022/topic/6695918 It was indicated there that this was unlikely to be fixed. Is there any kind of workaround available? Even if there was some functionality that didn't work but the library would still build, that would be better. Since the official Boost test platforms go all the way back to gcc 4.1.x, is it reasonable to assume that the library should be able to build on this version? Jason -- View this message in context: http://boost.2283326.n4.nabble.com/log-Compile-error-with-gcc-4-4-6-tp46461… Sent from the Boost - Users mailing list archive at Nabble.com.

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Reverse mpl set<>
by Chard 26 Apr '13

26 Apr '13

Please can someone post me the mpl to reverse an mpl::set<>. The mpl::reverse<> meta-function (unsurprisingly) requires a Front Extensible type, but I presume it's possible via a custom inserter. TIA.

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Numerical quadrature in Boost Math and Numerics libraries
by Mingfeng Qiu 26 Apr '13

26 Apr '13

Hi, I've been using the Boost.uBlas library for some time, but new to the mailing list and a novice in scientific computing. I'm sending my first post to ask whether there is a numerical quadrature routine to evaluate 2D integrals. It looks to me that there is no official library for this. Thank you for your help! Mingfeng

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Boost, MinGW and SjLj
by Archie Campbell 26 Apr '13

26 Apr '13

Hi, I have compiled boost_1_53_0 using bjam on windows with MinGW (gcc-4.6.3). I am using CodeBlocks for IDE and have successfully linked against Qt5. Attempting to link against libboost_serialization produces undefined references to things like sjlj_unwind and archive_exception. What's going wrong? Do I need to flag the compiler to change exception strategy? Thanks in advance. Archie

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Using C++ class with namespace in C
by Somostetoi Kilato 25 Apr '13

25 Apr '13

Hi, maybe it is not the best place to ask but at this moment I have no other idea where to go. This question is just a preamble for all the comming, BOOST related, questions of mine. So, I have a C++ class, the Apple, at the moment in the std namespace: class Apple { public: Apple(); void eat_an_apple(int p_bites); private: int bites; // number of bites to eat an apple }; I have a C application, an apple picker, first the header: typedef void CApple; #ifdef __cplusplus extern "C" { #endif CApple* pick_an_apple(); void eat_an_apple(const CApple *p_the_apple, int p_bites); void wash_your_hands(CApple *p_the_apple); #ifdef __cplusplus } // extern "C" #endif and the code, too: #include <stdio.h> #include "ApplePicker.hh" int main() { CApple *the_apple = NULL; the_apple = pick_an_apple(); eat_an_apple(the_apple, 9); wash_your_hands(the_apple); the_apple = NULL; return 0; } My question is, if I want to move my Apple class in a custom namespace, garden, how must I modify my C header and code file? Thank you and all the best, Kilato Somostetoi

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Is weak_ptr lock method thread safe?
by Andrea Galeazzi 25 Apr '13

25 Apr '13

I googled this question but, although there are many discussions about it, I didn't find a clear answer. Can I assume the following piece of code to be thread safe? shared_ptr<T> p1(new XXX); //Main thread weak_ptr<T> wp(sp); //Main thread //Then I run two threads: A and B p1.reset(); //thread A shared_ptr<T> p2 = wp.lock(); // thread B In other words, is lock method atomic in respect to deference of the shared point? -- korg Firma *KORG ITALY SPA* *Via Cagiata, 85 -- 60027 Osimo (AN) - ITALY* *Ph. +39 071 727161 -Fax +39 071 7231228* *P.IVA e Cod. fiscale IT01460580424* *Soggetta al controllo della Società KORG Inc. - Giappone* *Reg. Imprese di n. 212056/1996 del 23/12/96* *REA di Ancona al n. 133105 del 06/12/96* *Capitale sociale Euro 814.253,16 i.v.* Ai sensi del D.Lgs. 30 giugno 2003, n. 196, "Codice in materia di protezione dei dati personali" si precisa che le informazioni contenute nel messaggio sono riservate e destinate esclusivamente alla persona od organizzazione sopra indicata. A chi legge il presente avviso - se non è l'effettivo destinatario, o un dipendente, o la persona responsabile della consegna del messaggio - si notifica che sono proibite copie, distribuzione o divulgazione di quanto in esso contenuto (C.P. 616). Se questo messaggio Vi è pervenuto per errore, Vi preghiamo di informarci immediatamente, di non leggerlo e di distruggerlo. Grazie. /According to Legislative Decree n. 196 of 30 June 2003 about "Personal Data Protection Code" we point out that the information contained in this message may be privileged and confidential and is intended only for the use of the individual entity named above. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this message is strictly prohibited. If you have received this message in error, please notify us immediately and destroy the original message. //Thank you./

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