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what happened to the boost vault?
by Robert Ramey 23 Oct '05

23 Oct '05

It seems that the boost vault has a lot less in it than it used to. Is there a reason for this? Robert Ramey

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When to close ofstream in XML serialize
by Piyush Kapadia 23 Oct '05

23 Oct '05

In following function code, ofs.close() results in failure to write last end tag of XML archive, apparently because stream is closed before destructor is executed, so when do we execute ofs.close() ? ofs.flush does not help either or shell we skip executing any flush or close and just return from function ? template<class T> void Serialize(const char * filename) { std::ofstream ofs(filename); assert(ofs.good()); boost::archive::xml_oarchive oa(ofs); oa << BOOST_SERIALIZATION_NVP(T); ofs.close(); }

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[build] problem compiling current cvs
by Chris Hoeppler 23 Oct '05

23 Oct '05

Hi, I don't seem to be able to build a current cvs checkout of boost on a linux system on which I used to be able to build all the boost libraries by invoking 'bjam stage' on the cvs version of a couple of weeks ago. Did something change with respect to the build procedure? Invoking bjam on a clean cvs checkout results in the following output: ~/boost> bjam Building Boost.Regex with the optional Unicode/ICU support disabled. Please refer to the Boost.Regex documentation for more information (and if you don't know what ICU is then you probably don't need it). ...found 3548 targets... ~/boost> bjam stage Building Boost.Regex with the optional Unicode/ICU support disabled. Please refer to the Boost.Regex documentation for more information (and if you don't know what ICU is then you probably don't need it). don't know how to make stage ...found 1 target... ...can't find 1 target... Any idea what's going wrong here? Chris

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[general/iostreams/iterators] Why not a forward and/or a random access istream iterator?
by Mats Eklund 22 Oct '05

22 Oct '05

Hello, does anybody know whether there is something fundamentally wrong with designing an istream iterator that conforms with the forward, or even random access, iterator concepts? The std::istream_iterator conforms only with the simplest input iterator concept (stream need not support positioning). If a stream supports positioning, I cannot see why this should not work. If a streamable T has variable size on stream, we could do forward iteration, and if T has a known constant size on the stream, we could do random access iteration, right?! Since I haven't found any previous work in this direction on the web, I suspect there is a catch... (performance?) The only disadvantage I see, is that such iterators would have a rather different semantics from the std::(i)stream_iterator:s (equality etc), and that to create an end-iterator in the random access case, we cannot just rely on the default constructor, but need to pass in the stream, perhaps prepositioned at end. The original problem is to log/write data-records T on a persistant device, for which a std::stream(buf) interface is available. A reason for using the streambuf interface is that the log can support wrap-around functionality by simply using an intermediate streambuf that cares for necessary wrap-around functionality only, and otherwise just forwards transported characters to the device's streambuf. An enhanced std::istream_iterator would provide the log user with a convenient interface for reading records T out of the log. Thanks for any hints! /Mats

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Re: [Boost-users] Report from Mont Tremblant C++ Committee meeting
by Thore Karlsen 22 Oct '05

22 Oct '05

On Sun, 9 Oct 2005 21:32:30 -0400, "Beman Dawes" <bdawes(a)acm.org> wrote: [...] >String-algo : Interested, but concern over interface and choice of >functions, generic vs basic_string.5.3 separate proposal Any details on this? I love this library, and I would love to see it standardized in some form. Overall I've found the interface and function choices to be excellent (and I'd love to see even more), and I love that it's generic and not limited to basic_string. I use it on vectors and other containers for different kinds of network protocol parsing. -- Be seeing you.

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New version of mpl_math in the vault; problems compiling...
by Fredrik Hedman 22 Oct '05

22 Oct '05

Hello, I have been playing around with the examples of this fascinating code. This reports on the problems I have encountered so far. The latest examples are compiled with g++ 3.4.4 and '-Wall -Wno-long-long -pedantic -O2' using using boost-1_33 result in a number of errors: 1) The example in runtime_value.cpp gives boost/mpl/math/number_sign.hpp: No such file or directory This files seems to be missing. 2) The example double.cpp get a *lot* of warnings: mpl/math/double_/aux_/integral_exp.hpp:35: warning: comparison between signed and unsigned integer expressions Looking at the offending line it seems that the constants that are shifted should really be unsigned numbers: BOOST_STATIC_CONSTANT( boost::int16_t , exp1 = (number < (1 << (exp16 + exp8 + exp4 + exp2 + 1))) ? 0 : 1 -> BOOST_STATIC_CONSTANT( boost::int16_t , exp1 = (number < (1u << (exp16 + exp8 + exp4 + exp2 + 1))) ? 0 : 1 The same should probably be applied to all the other BOOST_STATIC_CONSTANT in struct integral_exp. Refactor 1u and 65536u into named constants? 3) The example big_integral.cpp complains about extra semicolons. It is the macro BOOST_MPL_MATH_BIG_INTEGRAL_AUX_CONVERT_IMPL_APPLY_RESULT in convert_base10_digits.hpp that is the root cause. By commenting out two ';' in the macro the example compiles and runs just fine: #define BOOST_MPL_MATH_BIG_INTEGRAL_AUX_CONVERT_IMPL_APPLY_RESULT \ BOOST_STATIC_CONSTANT( \ boost::uint32_t \ , a_0_0 = \ BOOST_PP_CAT( \ base10000_digit_ \ , BOOST_PP_DEC(BOOST_MPL_MATH_BIG_INTEGRAL_MANTISSA_SIZE) \ ) \ ); \ BOOST_PP_REPEAT( \ BOOST_PP_DEC(BOOST_MPL_MATH_BIG_INTEGRAL_MANTISSA_SIZE) \ , BOOST_MPL_MATH_BIG_INTEGRAL_AUX_A_0_MACRO \ , a_0_ \ ) /* ; removed extra */ \ BOOST_PP_FOR( \ (0) \ , BOOST_MPL_MATH_BIG_INTEGRAL_AUX_CONVERT_IMPL_PREDICATE_0 \ , BOOST_MPL_MATH_BIG_INTEGRAL_AUX_CONVERT_IMPL_NEXT_STATE_0 \ , BOOST_MPL_MATH_BIG_INTEGRAL_AUX_CONVERT_IMPL_MACRO_0 \ ) \ public: \ BOOST_PP_REPEAT( \ BOOST_MPL_MATH_BIG_INTEGRAL_MANTISSA_SIZE \ , BOOST_MPL_MATH_BIG_INTEGRAL_AUX_CONVERT_IMPL_MACRO_1 \ , digit_ \ ) /* ; removed extra */ \ /**/ -- Best Regards, Fredrik Hedman

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[Serialization] Loading from archive
by Sam Contapay 22 Oct '05

22 Oct '05

Sorry I tried to post this through the newsserver gateway. I didn't see the message show up after half and hour so I'm assuming it didn't post correctly as this email address wasn't subscribed. I apologize if it does ----------ORIGINAL EMAIL---------------- I've been trying to get loading from an archive to work for a couple of hours now. Maybe I'm missing something so I can use anyones "eyes" for help. This is a program written using VC7.1 and I do have RTTI on. I am able to save data from a MAP file to an ASCII text file using the serialize functions, but I'm having a problem getting that information back into my object. Here are some relevant code snippets if anyone can point me in the right direction it would be really appreciated. Also is their an archive that I can search? This news group is only leting me download like 100 messages. main class with serialize private: std::map<std::string, int> WordMapA; std::map<std::string, int> WordMapB; friend class boost::serialization::access; template <class Archive> void serialize(Archive & ar, const unsigned int version) { ar & WordMapA; ar & WordMapB; } Now here is my save and load save: // Save the bayes filter especially the map for later use std::ofstream ofs("BayesFilter.stb"); boost::archive::text_oarchive outarchive(ofs); outarchive << this; ofs.close(); load: std::ifstream ifs("BayesFilter.stb"); boost::archive::text_iarchive ia(ifs); CObjTest test; ia >> test; ifs.close(); When I save the file it saves to an ASCII file with no problems. When I then try to load the archive back all the Map data variables are still 0 after a call to the load function. I poured over the demo and its pretty much word for word so I don't know whats wrong any help... thanks. Sam

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Bug in XML serialization!!!
by Piyush Kapadia 21 Oct '05

21 Oct '05

Following code results in "unrecognized XML syntax" exception while writing to XML file. However if I change xml_oarchive to text_oarchive or binary_oarchive, it works fine, so I assume it's a bug in xml_oarchive ??? Does any one know how to fix this for xml_oarchive ??? #include <iostream> #include <fstream> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <boost/archive/binary_oarchive.hpp> #include <boost/serialization/vector.hpp> #include <boost/serialization/map.hpp> #include <vector> #include <map> #include <boost/archive/archive_exception.hpp> #include <boost/archive/basic_xml_archive.hpp> class base { protected : std::vector<int> vec; protected : friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(vec); } public : void add(int i) { vec.push_back(i); } int get(int idx) { return vec[idx]; } }; class derived : public base { friend class boost::serialization::access; std::map<std::string, int> hmap; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(boost::serialization::base_object<base>(*this)); ar & BOOST_SERIALIZATION_NVP(hmap); } public : void add(std::string str, int i) { hmap[str] = i; base::add(i); } int get(std::string str) { return hmap[str]; } }; int main(int argc, char* argv[]) { try { derived A; A.add("First", 12); A.add("Second", 34); const derived AA = A; std::ofstream ofs("Test.xml"); assert(ofs.good()); boost::archive::xml_oarchive oa(ofs); oa << BOOST_SERIALIZATION_NVP(AA); ofs.close(); derived B; std::ifstream ifs("Test.xml"); assert(ifs.good()); boost::archive::xml_iarchive ia(ifs); ia >> BOOST_SERIALIZATION_NVP(B); ifs.close(); } catch (boost::archive::xml_archive_exception ex) { std::cerr << " X " << ex.what() << std::endl; } catch (boost::archive::archive_exception ex) { std::cerr << " A " << ex.what() << std::endl; } catch (std::exception ex) { std::cerr << " E " << ex.what() << std::endl; } catch (...) { std::cerr << "Unknown Exception " << std::endl; } return 0; }

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[random] spot the stupidity competition
by Nigel Rantor 21 Oct '05

21 Oct '05

Hail all, Thanks for giving us the libraries, now only if we were all smart enough to use them properley the world would be at peace. As it is I've been having some problems with my own code that is wrapped around the random library. I'm playing around with a game I'm making and needed some randomness, games that are predicatble are just a tad boring... I need to generate numbers with lots of different distributions so creating one or two won't really cut it for me, there would have to be hundreds. Instead I went and basically ripped the random_number_generator described under decorators into two flavours and then created a bunch of overloaded functions that used them. The generators use a single real engine, currently mt19937;. Basically, everythnig works fine, except that calling seed( n ) on the engine doesn't effect the generators that hold a ref to it, which I found somewhat bizzare. So, after a few tweaks I ripped out the code and dumped it into a minimal test case and can see that the seed( n ) method works just fine when I pull raw numbers out of the engine, but still doesn't seem to effect the generators I've defined. I'm fairly sure this is my problem but I was wondering if anyone would be good enough to take a peek and tell me why exactly this isn't working. I did have a search on Gmane but couldn't find anything that looked related to my problem. I'm not sure what is the done thing on this list so I've attached source, if you want a makefile then I can oblige but it is a fairly small case. The test program reads in three numbers, the seed to use, the number of numbers to generate and the max to use when generating numbers from a distribution. Feeding it different seeds makes the raw number change, but not the others. I have also included the output of two runs to show you what I mean. TIA, N seed : 42 num : 10 max : 1000 seeded rng... 10 raw numbers from rng 1608637542 3421126067 4083286876 787846414 3143890026 3348747335 2571218620 2563451924 670094950 1914837113 10 random integers using rng 795 926 666 119 485 903 904 335 227 185 seed : 727364 num : 10 max : 1000 seeded rng... 10 raw numbers from rng 3240174879 3269238853 3044917573 2953574107 2463698974 2129367301 2064401652 2079989189 3644954707 1971100779 10 random integers using rng 795 926 666 119 485 903 904 335 227 185 #include "random.h" int random_num( int max ) { return int_gen( max ); } int random_num( int min, int max ) { return min + random_num( max ); } long random_num( long max ) { return long_gen( max ); } long random_num( long min, long max ) { return min + random_num( max ); } float random_num( float max ) { return float_gen( max ); } float random_num( float min, float max ) { return min + random_num( max ); } double random_num( double max ) { return double_gen( max ); } double random_num( double min, double max ) { return min + random_num( max ); } #ifndef RANDOM_H #define RANDOM_H #include <boost/random.hpp> using namespace boost; typedef mt19937 rng_type; template<class RNG, class IntType = long> class integer_random_number_generator { public: typedef RNG base_type; typedef IntType argument_type; typedef IntType result_type; integer_random_number_generator( base_type& rng ) : _rng( rng ) {} result_type operator()( argument_type n ) { typedef uniform_int<IntType> dist_type; return variate_generator<base_type&, dist_type>(_rng, dist_type(0, n-1))(); } private: base_type& _rng; }; template<class RNG, class RealType = double> class real_random_number_generator { public: typedef RNG base_type; typedef RealType argument_type; typedef RealType result_type; real_random_number_generator( base_type& rng ) : _rng( rng ) {} result_type operator()( argument_type n ) { typedef uniform_real<RealType> dist_type; return variate_generator<base_type&, dist_type>(_rng, dist_type(0, n-1))(); } private: base_type& _rng; }; static rng_type rng; static integer_random_number_generator<rng_type, int> int_gen( rng ); static integer_random_number_generator<rng_type, long> long_gen( rng ); static real_random_number_generator<rng_type, float> float_gen( rng ); static real_random_number_generator<rng_type, double> double_gen( rng ); int random_num( int max ); int random_num( int min, int max ); long random_num( long max ); long random_num( long min, long max ); float random_num( float max ); float random_num( float min, float max ); double random_num( double max ); double random_num( double min, double max ); #endif /* RANDOM_H */ #include "random.h" #include <iostream> using namespace std; int main( int argc, char ** argv ) { unsigned int seed; int num; int max; int i; cin >> ws >> seed; cin >> ws >> num; cin >> ws >> max; cout << "seed : " << seed << endl; cout << "num : " << num << endl; cout << "max : " << max << endl; rng.seed( seed ); cout << "seeded rng..." << endl; cout << num << " raw numbers from rng" << endl; for( i = 0; i < num; i++ ) { cout << rng() << endl; } cout << num << " random integers using rng" << endl; for( i = 0; i < num; i++ ) { cout << random_num( max ) << endl; } return 0; }

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Failures in Solaris/gcc build
by Fernando Mato Mira 21 Oct '05

21 Oct '05

Hello, I built Boost on Solaris 9 with gcc 3.3.3 but I saw many "...failed" messages while building. Also, in the destination lib directory there's no regex library, and I think there should be one. There are only the libraries for: libboost_filesystem libboost_iostreams libboost_prg_exec_monitor libboost_python libboost_signals Thanks

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