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boost.program_options no throw
by Aljaz 16 Jul '08

16 Jul '08

Hello I've been wondering if there is no-throw version of boost::program_options::store , command_line_parser and basic_line_parser ? Many thanks in advance!

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[math/distributions/poisson] extract Poisson-distributed random variate?
by Michael Fuller 16 Jul '08

16 Jul '08

I've searched the Boost documentation and mail archive, but I can't find an example for extracting a random variate from a Poisson distribution. What I want to do is similar to extracting a variate from a uniform distribution, such as the C++ rand() function, which returns a single random variate on the range [0, RAND_MAX]. Is there a way to do something similar using the Poisson distribution with a given mean? For example, something like this: double n, lambda(0.30); //lambda is the mean of the Poisson n = poisson_rand(lambda); Thanks, Mike

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boost interprocess
by Marc Magrans de Abril 16 Jul '08

16 Jul '08

Dear colleagues, I have been testing the boost interprocess library for two months in my spare time... everything looked ok until now. Perhaps I am doing something wrong, so be patient. As you can see in the code, I am trying to use the offset_ptr within a class named OffsetPtrClass. However, if I try to allocate the int inside the OffsetPtrClass cnstructor I'll get a segmentation fault in the getter (either the MASTER or the SLAVE forked processes). I a running on Linux kernel 2.6.16 and g++ 3.4.xx. What I am doing wrong? Thanks for your help, marc #include <iostream> #include <unistd.h> #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/offset_ptr.hpp> namespace ip=boost::interprocess; class OffsetPtrClass { public: OffsetPtrClass():myint_(0) { //If we allocate the int here we get a segmentation fault!! // //ip::managed_shared_memory segment(ip::open_only,"MySharedSegment"); //myint_ = static_cast<int*>(segment.allocate(sizeof(int))); } ~OffsetPtrClass() { } void setMyint(const int& myint) { *myint_ = myint; } int getMyint() { int myint = *myint_; return myint; } ip::offset_ptr<int> myint_; }; int main( int argc, char* argv[] ) { std::string shName("MySharedSegment"); pid_t pid = fork(); if (pid == 0) { try { std::cout << "CHILD: getpid() = " << getpid() << std::endl; std::cout << "CHILD: press return to continue..." <<std::endl; getchar(); ip::managed_shared_memory segment(ip::open_only, shName.c_str()); std::cout << "CHILD: Retrieving OffsetPtrClass 'optr' instance: " << std::endl; std::pair<OffsetPtrClass*, std::size_t> res; res = segment.find<OffsetPtrClass> ("optr"); assert(res.second == 1); OffsetPtrClass& optr =*(res.first); std::cout << "CHILD: 'optr'::getMyint() = " << optr.getMyint() << std::endl; std::cout << "CHILD: 'optr'::SetMyint(100)" << std::endl; optr.setMyint(100); } catch (...) { std::cerr << "CHILD: Something failed..." << std::endl; throw; } } else if (pid <0){ std::cerr << "---program.cc: Failed to fork" << std::endl; exit(1); } else { std::cout << "PARENT: getpid() = " << getpid() << std::endl; ip::shared_memory_object::remove(shName.c_str()); try{ std::cout << "PARENT: creating segment" << std::endl; ip::managed_shared_memory segment(ip::create_only, shName.c_str(), 65536); std::cout << "PARENT: creating OffsetPtrClass 'optr' instance" << std::endl; OffsetPtrClass& optr = *(segment.construct<OffsetPtrClass>("optr")()); //If we allocate the int here we do not have a segmentation fault optr.myint_ = static_cast<int*>(segment.allocate(sizeof(int))); std::cout << "PARENT: 'optr'::SetMyint(333)" << std::endl; optr.setMyint(333); std::cout << "PARENT: 'optr'::getMyint() = " << optr.getMyint() << std::endl; std::cout << "PARENT: 'optr'::*myint_() = " << *(optr.myint_) << std::endl; std::cout << "PARENT: press return to continue..." <<std::endl; getchar(); std::cout << "PARENT: 'optr'::getMyint() = " << optr.getMyint() << std::endl; } catch(...){ std::cerr << "PARENT:something failed... Everything is destroyed" << std::endl; throw; } std::cout << "PARENT: Shared memory destroyed" << std::endl; } }

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Re: [Boost-users] Boost serialization: is there a way to perform selective read
by Pavlo Korzhyk 16 Jul '08

16 Jul '08

> It's not there. boost::archive works sequentially on a stream and that's > it, so if you need to skip large portions of data you will have to > divide your data into multiple files and/or multiple chunks in one > stream. I did the latter and it works fine if you build some kind of > meta-information structure on where chunks begin and end. This enables > you to seek a specific chunk of data and process that with an archive. > > In any case, if you want to improve performance of your app use > (portable) binary instead of xml archives! You could take a look at http://code.google.com/p/hiberlite It will do what you need storing objects in sqlite database. There were no new releases for a couple of months, but I'll return to this project in a week. And there are _already_ enough features to solve the "selective access" problem. Yours sincerely, Pavlo Korzhyk ICQ#155870780

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boost.program_options - passing string or vector<string>
by Aljaz 16 Jul '08

16 Jul '08

Hello I want to use boost.program_options to parse commands for my program (console application) What I want to do is to be able to pass std::vector<std::string> of arguments or std::string (line) to parse_command_line(ac, av, desc); instead of char *argv, int argc. How is that possible? I've been looking at basic_command_line_parser class but couldnt figure out how it would be possible to do that, since converting string/vector of strings to array of char pointers would be really stupid. Many thanks for help Aljaz

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SVN tree : Issue with libstdcpp3.hpp
by Mathieu Peyréga 16 Jul '08

16 Jul '08

Hello, starting from line 66, I can find : #if defined(__GLIBCXX__) || (defined(__GLIBCPP__) && __GLIBCPP__>=20020514) // GCC >= 3.1.0 # define BOOST_STD_EXTENSION_NAMESPACE __gnu_cxx # define BOOST_HAS_SLIST # define BOOST_HAS_HASH # define BOOST_SLIST_HEADER <ext/slist> # if defined(__GLIBCXX__) && __GLIBCXX__ < 20071018 // GCC <= 4.3.0 # define BOOST_HASH_SET_HEADER <ext/hash_set> # define BOOST_HASH_MAP_HEADER <ext/hash_map> # else # define BOOST_HASH_SET_HEADER <backward/hash_set> # define BOOST_HASH_MAP_HEADER <backward/hash_map> # endif #endif on ubuntu 8.04 (64 bits) the 4.2.3 gcc version define __GLIBCXX__ as #define __GLIBCXX__ 20080329 so boost code prevents from using the ext headers when the backward headre do not exist (on my system)... Shouldn't the < be a > ? regards, Mathieu -- http://www.incub.net/

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serialization - How to retain protected access of non-default ctors
by George Verdad 16 Jul '08

16 Jul '08

Hi All, I am getting compiler errors using mingw 3.4.5 on the code below: error: `BaseClass::BaseClass(const std::string&)' is protected I tried to declare as friend the load_construct_data() override in BaseClass but gave me the following error: error: call of overloaded load_constuct_data(..) is ambiguous. What am I doing wrong? TIA, Gvv ... #include <boost/serialization/base_object.hpp> #include <boost/serialization/export.hpp> #include <boost/serialization/shared_ptr.hpp> #include <boost/serialization/list.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> template <class T> void Serialize(const T& t, std::string& OutData) { std::ostringstream ArchiveStream; boost::archive::text_oarchive Archive(ArchiveStream); Archive << t; OutData = ArchiveStream.str(); } template <class T> void Deserialize(T& t, const std::string& InData) { std::istringstream ArchiveStream(InData); boost::archive::text_iarchive Archive(ArchiveStream); Archive >> t; } class BaseClass : private boost::noncopyable { public: virtual ~BaseClass() {} const std::string& GetName() const { return Name; } protected: BaseClass(const std::string& name) : Name(name) {} private: std::string Name; template<class Archive> void serialize(Archive& ar, const unsigned int version) { ar & Name; } friend class boost::serialization::access; }; typedef boost::shared_ptr<BaseClass> BaseClassPtr; class DerivedClass : public BaseClass { public: DerivedClass(const std::string& name) : BaseClass(name) {} private: template<class Archive> void serialize(Archive& ar, const unsigned int version) { ar & boost::serialization::base_object<BaseClass>(*this); } friend class boost::serialization::access; }; BOOST_CLASS_EXPORT(DerivedClass) namespace boost { namespace serialization { template<class Archive> inline void save_construct_data(Archive& ar, const BaseClass* t, const unsigned int version) { ar << t->GetName(); } template<class Archive> inline void load_construct_data(Archive& ar, BaseClass* t, const unsigned int version) { std::string name; ar >> name; ::new(t)BaseClass(name); } template<class Archive> inline void save_construct_data(Archive& ar, const DerivedClass* t, const unsigned int version) { ar << t->GetName(); } template<class Archive> inline void load_construct_data(Archive& ar, DerivedClass* t, const unsigned int version) { std::string name; ar >> name; ::new(t)DerivedClass(name); } } } int main() { BaseClassPtr b(new DerivedClass("My name is gvv")); std::string data; std::cout << "Serialize" << std::endl; Serialize(b,data); std::cout << data << std::endl; b.reset(); std::cout << "Deserialize" << std::endl; Deserialize(b,data); std::cout << b->GetName() << std::endl; return 0; }

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[preprocessor] BOOST_PP_IF with BOOST_PP_SEQ_ENUM as then-argument
by Maximilian Matthe 16 Jul '08

16 Jul '08

Hello! #define seq (int)(int) BOOST_PP_IF(1, BOOST_PP_SEQ_ENUM(seq), BOOST_PP_EMTPY) does not expand to what i want: it should be int, int . G++ gives the following error: test.cpp:20:1: macro "BOOST_PP_IIF" passed 4 arguments, but takes just 3 BOOST_PP_IIF which is logical, because SEQ_ENUM expands to int, int and so if gets 4 arguments. I tried to surround SEQ_ENUM with IDENTITY but it's the same problem. Only surrounding SEQ_ENUM with () works, but then I have the () in the code, which I do not want. How can I solve this problem? Max

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Basic Conversion to Boost Graph Library Data Structure
by Lex Fridman 16 Jul '08

16 Jul '08

I know that what I'm asking is in the documentation, but I haven't been able to figure it out from just looking through it on a couple passes. I would like to convert my graph adjacency list to the BGL adjacency_list. Each node is represented with the Node data structure, and so is each edge. I also have "global" properties for the graph as a whole. So here are the three data structures my graph uses: GraphNode { int foo; double bar; } GraphEdge { double weight; bool fun; } GraphGlobals { string graphName; } How do I declare an adjacency_list that will uses these representations of the node, edge, and global parameters? Thanks. -- View this message in context: http://www.nabble.com/Basic-Conversion-to-Boost-Graph-Library-Data-Structur… Sent from the Boost - Users mailing list archive at Nabble.com.

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Boost serialization: is there a way to perform selective read
by ari vol 16 Jul '08

16 Jul '08

Hey, I would like to know whether there is a way to preform selective read using Boost serialization, thus reading serialized instance with its id/key. The implementation that i know is saving instances to a file and then loading them all according to the saving order. Is there a way to read only one selected instance from the file. Thanks, -Ariella

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