- Boost-users - lists.boost.org

[Who's using boost?] Algocoders : books on c++11, Boost and Beyond
by Algocoders . 03 Dec '12

03 Dec '12

Algocoders <http://www.algocoders.com> Algocoders has been using boost since last 6+ years with a mission to help people build a better software eco-system by standing on the shoulder of giants. If it wasn't not for boost, then it could have been really difficult for us to build our framework based on sound mathematical foundation of computer science using modern C++. It is the pioneering efforts at boost towards "Using and Extending C++11, Boost and Beyond" which has motivated us to devote ourself in developing bullet-size capsules in the form of tiny booklets with industrial-set framework to lift the thin veil with initial focus on practical usage of C++11 vis-a-vis mathematical foundation behind it. Web Page : http://www.algocoders.com Enthused by boost, we are working tirelessly towards *publishing a series of books(or booklets) which will bridge the gap between esoteric and street-side ones. Initial focus will be on C++11, Boost, Loki, STL, Algorithms, Data Structures, Multi-threading, Design Patterns, gcc, clang, valgrind.* *First book in this series is :*(will be available by end of November 2012) *Foundation of Algorithms in C++11, Volume 1* Using and Extending C++11, Boost and BeyondList of books(in progress): - *C++11 Algorithms : *Using and Extending C++11, Boost and Beyond - *Smart Pointers** : Tips and Techniques in C++ :* Using and Extending C++11, Boost and Beyond - *C++11 FAQs :* Using and Extending C++11, Boost and Beyond - *Concepts & Traits C++ **:* Using and Extending C++11, Boost and Beyond and so on. We use almost all the libraries under boost including trunk and branches, especially Spirit, Phoenix, Proto, MPL, Fusion to mention a few. Thanks, Algocoders www.algocoders.com

2 2

boost managed shared memory: RUN FAILED
by Olivier Austina 03 Dec '12

03 Dec '12

Hello, I try to run an example from this online book( http://en.highscore.de/cpp/boost/interprocesscommunication.html) and I got "RUN FAILED (exit value 1, total time: 938ms) ". I am using Netbeans. This is the example: #include <boost/interprocess/managed_shared_memory.hpp> #include <iostream> int main() { boost::interprocess::shared_memory_object::remove("Highscore"); boost::interprocess::managed_shared_memory managed_shm(boost::interprocess::open_or_create, "Highscore", 1024); int *i = managed_shm.construct<int>("Integer")(99); std::cout << *i << std::endl; std::pair<int*, std::size_t> p = managed_shm.find<int>("Integer"); if (p.first) std::cout << *p.first << std::endl; } Thanks very much. -- Regards Austina

2 3

Serialization newbie, memory being overwritten?
by Lasse Laursen 03 Dec '12

03 Dec '12

Hello to you, I wonder if you might be able to solve this conundrum I've been pondering. The boost (1.51) serialization library is giving me some trouble. I've been battling back and forth with the library, and I'm beginning to think I'm missing some key element. At first, I had issues to just getting things written out to a file without crashes. As far as I could tell, this particular problem was compounded by the fact, that I tried to simplify my code by just writing a single primitive referenced by a pointer to an object containing said primitive. As I've since come to learn, serializing pointed-to primitives is apparently not trivial. I have since, gotten the serialization class to properly write out a few simple member primitives from my class, but when I read them back using the exact same function, it seems as though a lot - if not all - of the pre-existing data in the object, which I am not serializing, gets overwritten. As far as I have been able to tell from the tutorials, I am doing everything exactly by the book. I was also concerned that maybe boost doesn't allow partial serialization, but this shouldn't be an issue either as far as I can tell. I must be making some sort of colossal mistake that I just cannot see. My in and out code is fairly straight forward: std::string streamPath = PTMFilePath.string(); std::ifstream ifs(streamPath); boost::archive::xml_iarchive ia(ifs); ia >> BOOST_SERIALIZATION_NVP(aStream); ----- std::string streamPath = PTMFilePath.string(); std::ofstream ofs(streamPath); boost::archive::xml_oarchive oa(ofs); oa << BOOST_SERIALIZATION_NVP(aStream); ------ My serialization function: template<class Archive> void serialize(Archive &ar, const unsigned int file_version) { ar & BOOST_SERIALIZATION_NVP(nrOfSamples); } ------ aStream is a pointer to a custom class, where I have allowed boost access. I am really confused as to what is causing this. Both pointed to data and regular primitives in the aStream class are wiped/altered as soon as the program enteres the serialize function, and even before the actual data seems to be read. I must be overlooking something really basic here. I hope someone can whack me with the solution stick... Thanks, Lasse

3 6

Incorrect assertion in Boost.Exception?
by Thorsten Dahlheimer 02 Dec '12

02 Dec '12

Hello, we want to use Boost.Exception (1.47.0) with MS Visual Studio 2010 in a project that consists of several DLLs and a main executable. We have situations where we store an error_info into an exception from inside a DLL and access it again from another DLL/the EXE, e.g.: dll.cpp: void func() { BOOST_THROW_EXCEPTION(my_exception() << my_info(42)); } exe.cpp: try { func(); } catch (boost::exception& e) { std::cout << *boost::get_error_info<my_info>(e) << std::endl; } Now at runtime, when the error info is accessed, the following assertion in boost::exception_detail::error_info_container_impl::get() fails: BOOST_ASSERT( BOOST_EXCEPTION_DYNAMIC_TYPEID(*p).type_==ti.type_ ); As far as we can see, this happens because MSVC++ uses seperate type_info objects in each dll/exe, and the above assertion compares pointers to type_infos instead of the objects themselves. We believe this is a bug on the Boost side, since type_info objects for the same type are generally not guaranteed to be unique. Are we correct with that? Thanks, Thorsten

2 2

Re: [Boost-users] boost shared memory: vector of objets
by Olivier Austina 02 Dec '12

02 Dec '12

Hello, I am using gcc 4.5.3 and boost 1.48 ( Netbeans with Cygwin 4.x on Windows XP SP3). Thank you. Regards Austina -- Regards Austina

1 0

boost shared memory vector objetc
by Olivier Austina 02 Dec '12

02 Dec '12

Hello, Please can somebody help me on this code (from boost site). I try to run it but I still get the following error: */cygdrive/C/Program Files/NetBeans 7.1.2/ide/bin/nativeexecution/dorun.sh: line 33: 12900 Segmentation fault (core dumped) sh "${SHFILE}" Press [Enter] to close the terminal ...* This is the code for creating vector in shared memory: #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/containers/vector.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <string> #include <cstdlib> //std::system using namespace boost::interprocess; //Define an STL compatible allocator of ints that allocates from the managed_shared_memory. //This allocator will allow placing containers in the segment typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator; //Alias a vector that uses the previous STL-like allocator so that allocates //its values from the segment typedef vector<int, ShmemAllocator> MyVector; //Main function. For parent process argc == 1, for child process argc == 2 int main(int argc, char *argv[]) { if(argc == 1){ //Parent process //Remove shared memory on construction and destruction struct shm_remove { shm_remove() { shared_memory_object::remove("MySharedMemory"); } ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); } } remover; //Create a new segment with given name and size managed_shared_memory segment(create_only, "MySharedMemory", 65536); //Initialize shared memory STL-compatible allocator const ShmemAllocator alloc_inst (segment.get_segment_manager()); //Construct a vector named "MyVector" in shared memory with argument alloc_inst *MyVector *myvector = segment.construct<MyVector>("MyVector")(alloc_inst);* * ;* } else{ // some code } return 0; }; I got an error for this instruction: *MyVector *myvector = segment.construct<MyVector>("MyVector")(alloc_inst); *This addition information about the environnment: NetBeans 7.1.2 with Cygwin_4.x, gcc-core 3.4.4-999, gcc-g++ 3.4.4-999,gcc-mingw-core 20050522-3,gcc-mingw-g++ 20050522-3 ,gcc4-core 4.5.3-3 , gcc4-g++ 4.5.3-3 , gdb 7.5.50-1. I am using Windows XP SP3. Many thanks. -- Regards Austina

2 2

Re: [Boost-users] Boost 1.49.0 compilation issue
by Shcherbina Vladimir 02 Dec '12

02 Dec '12

I tried to compile this code with Boost 1.46.1 and everything was OK! So, we have a problem with atleast 1.49 and up Vladimir The information in this e-mail transmission contains proprietary and business sensitive information. Unauthorized interception of this e-mail may constitute a violation of law. If you are not the intended recipient, you are hereby notified that any review, dissemination, distribution or duplication of this communication is strictly prohibited. You are also asked to contact the sender by reply email and immediately destroy all copies of the original message.

1 0

Re: [Boost-users] [Range & c++0x Lambdas] Can this be done?
by John M. Dlugosz 01 Dec '12

01 Dec '12

I had the same issue and posted it a few months ago. I wrote to the MS VS forum that their std::result_of should work correctly with both old and new formats; in particular use the declared result_type if it exists (which in general lets the user override the deduced type, great for compatibility issues). Actually doing that robustly is a bit of a maze of metaprogramming. I ended up making a local my_namespace::result_of that I just handles what I needed, and only when I asked for it. That doesn't help the existing range templates, but such a change could be put back into boost::result_of. Meanwhile, for different reasons, I made a macro that abstracts the different syntax between C++11 lambdas and Apple Block Closures. The latter generates a suitable lambda class complete with result_of member. That makes me think that you could have a macro that wraps a compiler-generated lambda expression in another class that inherits the operator() etc. and adds in the result_of typedef to simply use decltype. —John Date: Wed, 21 Nov 2012 10:15:18 -0700 From: Nathan Crookston <nathan.crookston(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [Range & c++0x Lambdas] Can this be done? Message-ID: <CAMb0s=1qtLcOiXTd5h7b2qkOSiYqjEVeN-m=rafJRHKDU6y6Cg(a)mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" Rob, On Wed, Nov 21, 2012 at 6:39 AM, Robert Jones <robertgbjones(a)gmail.com>wrote: >> Can the last line, labelled NOT Ok, be made to work? I think the lambda >> does >> not publish its result as a bind does, so I suspect it's hopeless. Any >> thoughts? >> // NOT Ok >> boost::range::push_back( out, in | transformed( []( S & s ) { return >> s.i; } ) ); >> } >> >> It seems trivial to have a nested result_type in all cases with a lambda. > However, in C++11 there's no need for it due to decltype. > > Sadly, some compilers fall into a gap where result_of (boost or std) > doesn't use decltype and lambdas don't publish tr1-style result_type -- > leaving code like the above in the lurch. > > Michel Morin wrote some code for adapting such a case which may be of > interest to you: http://lists.boost.org/boost-users/2012/01/72879.php > > HTH, > Nate >

5 21

Boost.Wave getting raw input tokens for code transformation
by Frank Birbacher 30 Nov '12

30 Nov '12

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi! I'm trying to utilize Wave for simple code transformations. My starting point is to do an identity mapping through Wave: read in a source file, tokenize it, and output it again. The output shall be the same as the input on a byte by byte basis. I modified the cpp_lexer example to just output the token.value() texts. From that I discovered whitespace in "# define" will be dropped. Ok, fixed this by modifying Wave source code. Now my main problem are line continuations using backslash like in multiline macro definitions. Those get processed at a very low level, I guess. The backslash will never be reported as a token, but the adjacent characters will be fused into one token. Is there a way to define a "raw" token mode that would report the backslash and keep the adjacent characters as distinct tokens? I don't understand the tokenizer level at all. Frank -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: keyserver x-hkp://pool.sks-keyservers.net iEYEARECAAYFAlC1w/8ACgkQhAOUmAZhnmrUsQCeIVBxkYTUg1qIU2DTsSZuh5u1 2v8AniMF44HV4agBashrP81N6XN3bTW1 =A8Sp -----END PGP SIGNATURE-----

2 2

serialization of recursive objects
by kean 29 Nov '12

29 Nov '12

Hello everybody, I defined the following objects to be serialized: class MyElementObject { friend class boost::serialization::access; public: template<class Archive> void serialize(Archive & ar, const unsigned int version) { } }; template<class T> class MyRecursiveObject { friend class boost::serialization::access; public: T element; std::vector<MyRecursiveObject<T> > children; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & element; ar & children; } }; I then run the following code: int main() { //MyRecursiveObject initialization MyRecursiveObject<MyElementObject> rec_object; rec_object.children.push_back(MyRecursiveObject<MyElementObject>()); rec_object.children[0].children.push_back(MyRecursiveObject<MyElementObject>()); //create vector of pointers to MyRecursiveObject's elements vector<MyElementObject *> elt_ptrs; elt_ptrs.push_back(&rec_object.element); elt_ptrs.push_back(&rec_object.children[0].element); elt_ptrs.push_back(&rec_object.children[0].children[0].element); //serialize MyRecursiveObject and the vector of pointers { ofstream ofs("filename"); boost::archive::text_oarchive oa(ofs); oa << rec_object; oa << elt_ptrs; } //create new MyRecursiveObject and vector of pointers for deserialization MyRecursiveObject<MyElementObject> rec_object_deserialized; rec_object_deserialized.children.push_back(MyRecursiveObject<MyElementObject>()); rec_object_deserialized.children[0].children.push_back(MyRecursiveObject<MyElementObject>()); vector<MyElementObject *> elt_ptrs_deserialized; //deserialize { ifstream ifs("filename"); boost::archive::text_iarchive ia(ifs); ia >> rec_object_deserialized; ia >> elt_ptrs_deserialized; } //compare deserialized pointers cout<<"elt_ptrs first level="<<elt_ptrs_deserialized[0] <<" expected="<<&rec_object_deserialized.element<<endl; cout<<"elt_ptrs second level="<<elt_ptrs_deserialized[1] <<" expected="<<&rec_object_deserialized.children[0].element<<endl; cout<<"elt_ptrs third level="<<elt_ptrs_deserialized[2] <<" expected="<<&rec_object_deserialized.children[0].children[0].element<<endl; return 0; } And I always get an output similar to the following one: elt_ptrs first level=<b>0x7fff57c787c0* expected=*0x7fff57c787c0* elt_ptrs second level=*0x18e7020* expected=*0x18e7020* elt_ptrs third level=*0xffff8000ab5564f0* expected=*0x18e7450* As can be seen from the output I manage to deserialize pointers that point to elements down to the second recursion level of MyRecursiveObject. As soon as I try to do it with pointers to the third level or even deeper the deserialization fails. Am I using boost::serialization wrongly? Note that the MyRecursiveObject is always successfully deserialized, no matter how many levels it has. I encounter the problem only deserializing pointers to its elements. Thank you in advance Kean -- View this message in context: http://boost.2283326.n4.nabble.com/serialization-of-recursive-objects-tp463… Sent from the Boost - Users mailing list archive at Nabble.com.

2 1