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[xpressive] un-used variables
by Jeff Flinn 07 Nov '07

07 Nov '07

We compile our app with -Wunused-variables on the Mac with gcc 4.0. We get several unused variable warnings due to <boost/xpressive/regex_primitives.hpp>. Is there some facility for quieting these from xpressive itself? We currently are using #pragma unused ( eol, ...) to quiet the list of about 15 unused variables. Thanks, Jeff Flinn

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[BGL] property_map not compiling because it's not l-value?
by Ferng, Andrew D 07 Nov '07

07 Nov '07

Hi, I'm trying to use the concepts in the Kevin Bacon example in my code and am having trouble with compiling. http://www.boost.org/libs/graph/doc/kevin_bacon.html When I compiled the example by itself, it ran fine. However when I changed it to my data, then it gave me a compile error of "error C2106: '=' : left operand must be l-value" I don't know why this is, other than variable name, I just changed the vertex type from string to index. Nothing that I can see would cause this. The line not compiling is "grid_id[u] = gid;" See below for code. ************************************************************************ **************************** typedef property_map<ConnectionGraph, vertex_index_t>::type vertexID_MapType; typedef property_map<ConnectionGraph, edge_index_t>::type edgeID_MapType; vertexID_MapType grid_id = get(vertex_index, interfaceGraph); edgeID_MapType connectingElement_id = get(edge_index, interfaceGraph); typedef graph_traits<ConnectionGraph>::vertex_descriptor Vertex; typedef std::map<long,Vertex> NameVertexMap; NameVertexMap edges; for(CELAS2::iterator itr = CELAS2s.begin();itr != CELAS2s.end(); ++itr ) { long gid = (*itr)->getSideA_1Grid(); NameVertexMap::iterator pos; bool inserted = false; Vertex u, v; tie(pos, inserted) = edges.insert(std::make_pair(gid, Vertex())); if (inserted) { u = add_vertex(interfaceGraph); grid_id[u] = gid; <<<<-------- ************ this is the line that VS is saying non l-value. **************** pos->second = u; } else u = pos->second; } ************************************************************************ *************************** Any ideas why this is? I'm confused as to what's causing this. Any other way to populate the property map? I'm using VS2005 and boost 1.33.1. Thanks!

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ublas::vector<A>
by e r 07 Nov '07

07 Nov '07

hi, is it possible to do ublas::vector<A> vec; where A is a class that i define, not a built in type? if so, what are the requirements on A?

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boost.python switching from v2.5 to v2.4
by desai3＠cooper.edu 06 Nov '07

06 Nov '07

Hi all: I have used Boost.Python successfully to wrap around C++ API in python2.5. I must say that boost.python is an amazing library. However, if I want to create the same API for python2.4 do I have to rebuild the boost with python2.4 and then run bjam again, or is there any simple solution than that? The reason for asking this is because changing the Jamrules file did not help much. Thank you for your help. Maulik

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[filesystem] Apparent non-compliant code in current operations.hpp, ...
by Marty Fried 06 Nov '07

06 Nov '07

While building 1_34_1 on various platforms we support, I came across some compile errors for the AIX compiler, xlC/vacpp that weren't caught by gcc or MSVC, possibly due to being hidden by a level of indirection. The errors were mostly undefined classes where the template class was fully defined at the time of instantiation. I apologize if my explanation isn't clear or totally correct - I'm not an expert on the C++ standard, and got a lot of the actual explanation from coworkers that know it better than I do. But it's up to me to do the actual reporting and to try to get it to work for us on all the platforms we support. My original post was a few days ago, with the subject "[filesystem] vacpp errors building 1_34_1 filesystem library on AIX". I am because it may look like a vacpp problem, which is an unsupported compiler, but it's not really. It just happens that xlC was the only compiler that caught the error, I think. My original post can also be read at this link: http://permalink.gmane.org/gmane.comp.lib.boost.user/31028 The problem is that the class basic_directory_iterator is not fully defined until after it is used by remove_all(). There were a few other similar errors which I can provide if someone takes an interest in this. If I am wrong, or if there is a reason this won't be fixed, it would be helpful to know, so we can decide what to do. -- Marty Fried Senior Software Developer, Aldon USA http://www.aldon.com

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boost timers
by Mark Wyszomierski 06 Nov '07

06 Nov '07

Hi, Do any of the boost timer methods allow elapsed time to be measured in a separate thread? Something like: int main() { boost_thread timer; timer.Start(); while () { // some timeout. sleep(5000); // check how much time has passed. cout << timer.GetElapsedTime() << endl; } return 0; } Thanks

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[program options] storing values into a set instead of vector?
by Ovanes Markarian 06 Nov '07

06 Nov '07

Hello all! I would like to allow only unique parameters to be stored: param = X param = Y param = X should result in a collection of {X, Y} Therefore I want my params to be stored in a set instead of vector? Is there any chance to implement/specify it without putting the params into the vector of strings and re-inserting them into a set? Doing it the way: value<string_set>() result in an error. Some other question? As I see "program options" works only with basic_strings<charT>, where it is assumed that the traits class is default. What if I wish to specify my traits class for the basic_string will it work? Many thanks! Ovanes

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Starting ThreadClass including Mutexes
by Honki 06 Nov '07

06 Nov '07

Hi boost-users, I'm new in the mailing list, so I hope, that I'm right here and you can help me. I want to start a ThreadClass that includes some boost::mutex variables, but it doesn't work because of the "noncopyable" definition of the mutex-class. *******************MyClass******************* ...... class OutputProcessor_C { public: ClientOutputProcessor_C(); virtual ~ClientOutputProcessor_C(); void operator()() { while( true ) { boost::xtime wakeUpTime; boost::xtime_get(&wakeUpTime, boost::TIME_UTC); wakeUpTime.sec += ( 0.05 ); boost::thread::sleep( wakeUpTime ); Process(); } } protected: void Process(); boost::mutex m_publishDataMutex; ...... ********************************************* *******************MyMain******************** ...... int main(int argc, char* argv[]) { // Classpointer boost::shared_ptr<OutputProcessor_C()> outputProcessor(new OutputProcessor_C()); // generate Thread boost::shared_ptr<boost::thread> threadOutputProcessor(new boost::thread(*outputProcessor)); ...... ********************************************* When I tried to compile the source code, there is an error - "It is not possible to copy the constructor for the class 'boost::mutex'". Where is the problem? I don't want to copy anything. If it is not possible to generate a simple thread class that includes some mutexes, that is really weak. Greetings, Matthias

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[thread] static mutex construction
by Pedro Lamarão 06 Nov '07

06 Nov '07

Hello all, I've been wondering how boost::mutex plays in the static initialization game. I'm toying with a "plugin" system where plugins statically register with a singleton plugin_manager using a helper struct like this: template <typename PluginT> struct register_plugin { register_plugin () { shared_ptr<plugin_base> ptr(new PluginT); plugin_manager::instance().register(ptr); } }; static register_plugin objects, specialized for each plugin type, are constructed in an anonymous namespace to register the plugin at static initialization time, like so: namespace { register_plugin<foo_plugin> rp; } plugin_manager::instance() looks like: { static plugin_manager* s_instance; // s_mutex is a static member { boost::mutex::scoped_lock lock(s_mutex); if (s_instance == 0) { s_instance = new plugin_manager; } } return *s_instance; } So far I've implemented two plugins in this application and everything just works. It seems to me there is a static initialization race between every register_plugin object and plugin_manager::s_mutex. Am I just lucky or is there some magic about mutexes in this regard? I'm working on a Fedora 7 i386 system. -- Pedro Lamarão

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[crc] Easy way to get the "correct checksum" constant?
by Norbert Unterberg 06 Nov '07

06 Nov '07

Some CRC algorithms (when using 0xFFFF as an initial value and final XOR) have a nice property that then checking the consistency of a data block that has a CRC checksum appended, the resulting checksum value is a constant. Is there an easy way to extract this constant value from boost::crc directly? Example: We use a CRC like this: typedef boost::crc_optimal<16, 0x1021, 0xFFFF, 0xFFFF, true, true> crc_type; When sending a block of data, we append the generated CRC. The receiver side feeds the complete block incluing the CRC bytes into its generator. When the data block has no errors, the crc.checksum() is always exactly 0x0F47. Currently, I manually calculate that constant by something like this: crc_type crc; crc_type::value_type val(0); crc.process_bytes(&val, sizeof(val)); m_key = crc.checksum(); Is there an easier way to extract this "crc is correct" value? Norbert

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boost-users [boost::function] template.
by chun ping wang 04 Nov '07

04 Nov '07

Hi I have a problem with boost::function in association with template. I have a gain function declaration declare as this.. template < template <typename ELEM,typename = std::allocator<ELEM> > class CONT, typename T, typename U > long double gain(const CONT<boost::unordered_map<T, U> >& data, const T& attr, const T& target_attr); // old signature does compile template < template <typename ELEM,typename = std::allocator<ELEM> > class CONT, typename T, typename U > boost::any ID3( const CONT<boost::unordered_map<T, U> >&, const T&, const CONT<T> &, boost::function<long double (const CONT<boost::unordered_map<T, U> >&, const T&, const T&) > ); // new signature DOES NOT compile. template < template <typename ELEM,typename = std::allocator<ELEM> > class CONT, typename T, typename U > boost::any ID3( const CONT<boost::unordered_map<T, U> >&, const T&, CONT<T> *, boost::function<long double (const CONT<boost::unordered_map<T, U> >&, const T&, const T&) > ); In the main file i have things pass as this. // old way of passing works with old signature boost::any tree( MyAnn::ID3<std::vector, std::string, std::string>(data, target_attr, attribute, MyAnn::gain<std::vector, std::string, std::string>) ); // line 76 to 82. boost::function<long double (const std::vector<boost::unordered_map<std::string, std::string>&, const std::string&, const std::string&)> gainfunc; gainfunc = MyAnn::gain<std::vector, std::string, std::string>; boost::any tree( MyAnn::ID3<std::vector, std::string, std::string>(data, target_attr, boost::addressof(attribute), gainfunc) ); I compile the file and get teh following errors. Can anyone tell me why changing the orginial signature from const CONT<T>& to CONT<T> * all of sudden breaks the code. Thanks.

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回复： [Boost-users] "Getting Started" document : missing documentation of the stdlib flag
by 鑫赖 04 Nov '07

04 Nov '07

Hi: Thank you.I try it! _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users ___________________________________________________________ 雅虎邮箱，终生伙伴！ http://mail.yahoo.com.cn/

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回复： [Boost-users] How can change library name!
by 鑫赖 04 Nov '07

04 Nov '07

The "p" in the name means that you are using STLport: and that means you must use STLport when you build the regex lib as well. Take a look at the getting started guide for instructions, but you should end up with a "p" in the name once regex has been built against STLport. Hi, John: Thank you very much. So how to build boost library with STLPort, or can you tell me where to find the documents.I have read boost document, but I can't find instruction! Robin ___________________________________________________________ @yahoo.cn 新域名、无限量，快来抢注！ http://mail.yahoo.cn/

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Serializing abstract classes
by Christoph 03 Nov '07

03 Nov '07

Consider the following class hierarchy: A - B - C1 \- B2 - C2 Is the following correct: * when A is an abstract class then (without any data members!) then I do not need to provide serialization support for this class * when A does have data members (and so does C) but B does not add any data and B furthermore is abstract (so the actuall class will be C1..) then no searialization support is needed for B? Is this correct? Should I provide serialization support for these classes even *if* it is correct? Best regards and thank you Christoph

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boost::concept_check: ConceptConcept missing!
by Mattias Nissler 03 Nov '07

03 Nov '07

Hi, I've just recently started using boost::concept_check. It suits my needs very well and works perfectly so far. However, today I've come across something that is missing: The ConceptConcept! What I mean is a meta concept that checks whether a given template is a concept checking class. It should be relatively straightforward to implement, here is some example code I've cooked up: #include <boost/concept_check.hpp> template<template<typename T> class _TConcept> struct ConceptConcept { /* Instead of int, any type allowed as template parameter should do. */ _TConcept<int> c; void constraints() { /* Require the constraints() function to exist in _TConcept. */ c.constraints(); } }; template<template<typename TX> class T> void function() { boost::function_requires< ConceptConcept<T> >(); } template<typename T> struct NoConcept { }; int main(void) { function<boost::IntegerConcept>(); //function<NoConcept>(); // <- fails, NoConcept::constraints() is missing. } Note that due to the template template technique, this only works for ConceptConcept. Higher meta levels (e.g. ConceptConceptConcept) are not supported by this code. I'd like to see this in boost::concept_check. What do you think? Cheers, - Mattias

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"Getting Started" document : missing documentation of the stdlib flag
by Vincent Torri 03 Nov '07

03 Nov '07

Hello, If I'm not mistaken, to compile boost with STLport, one must pass -stdlib=stlport (or something like that) to bjam. But it's not mentionned in the "Getiing Started" documentation (Unix or Windows), while STLport itself is mentioned. Also, stdlib is mentioned when I launch bjam with --help, --help-options or --help-internal. Can someone add the documentation of the stdlib flag in "Getting Started", please ? (and maybe also in the boost build, to get doc with bjam --help) Thank you Vincent Torri

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How can change library name!
by 鑫赖 03 Nov '07

03 Nov '07

When i build boost library, how can i use "bjam" to control the library naming rules and compiler flags. i use vs2005. when i use regrex library, vc2005 always says that "can't link library boost-regrex-p-1_34_1.lib",but the library name that "bjam" produce is "boost-regrex-1_34_1.lib". The library name i can't remenber clearly,but the difference is character "p". So i want to control the the library naming rules. i don't why vc2005 link boost-regrex-p-1_34_1.lib,not other name just as the "bjam" produced. so i don't familiar with the rules vc2005 link library. ___________________________________________________________ 雅虎邮箱，终生伙伴！ http://mail.yahoo.com.cn/

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SFINAE broken in Visual C++ Express?
by Ovanes Markarian 03 Nov '07

03 Nov '07

Hello! Does anybody else experience a problem using enable_if templates in Visual C++ Express 2005 SP1? I get compiler errors in this code: template<class LookUpType_> typename boost::enable_if_c<is_const, result_type>::type at(LookUpType_ const& key)const { return has_key(view_, key); } template<class LookUpType_> typename boost::disable_if_c<is_const, result_type>::type at(LookUpType_ const& key) { return has_key(view_, key); } It blames that type is not a member of enable_if_c or disable_if_c? This is really strance, since this should not be considered by compiler as a possible template instantiation. is_const is an enum value containing either true or false.

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Mixing Boost thread library and Apache runtime library
by Alex 02 Nov '07

02 Nov '07

Hi, Our current code base uses Apache Runtime Library for handling multithreading code, including threads, concurrency control, etc. We are currently starting to convert to the Boost thread library. During the conversion which might take a while we would like to be able to mix the threads from the APR library with concurrency control objects (mutexes) from the Boost library. Is this ok to do this or will we run into some strange issues? We are currently running the code on Windows and Linux. Please let me know if I can provide any specifics about the APR library to better answer this question. Thank you! Alex

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boost Xpress and Window CE 5.0..help me..!!
by bsakiag 02 Nov '07

02 Nov '07

Hi, all. I want to use boost Xpress on Windows CE 5.0 (w/VS2005) when compile sample code, error occors reason of "btowc()" function. if I comment out ////////////////////////// c_regex_traits.hpp ///////////////////////// #ifndef BOOST_XPRESSIVE_NO_WREGEX /// INTERNAL ONLY template<> inline wchar_t c_regex_traits<wchar_t>::widen(char ch) { using namespace std; return btowc(ch); <<-------------- here!!! } #endif ////////////////////////////////////////////////////////////////////// this function not supported in Windows CE. is there any solution of the compile error? regards, from bstill. ps: when I compile with "BOOST_XPRESSIVE_NO_WREGEX" preprossor, another errors are occur. ________________________________________________________ 존경하는 선생님께 고마움의 메시지 보내고 선물 받으세요! - 모두가 행복한 세상이 됩니다. UCC 참여하기 http://kr.fun.kids.yahoo.com/funnybox/thankyou.html

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Is anyone going to tell me the way to set the WINDOWS variables for BOOST?
by question boost 02 Nov '07

02 Nov '07

Hi, in the boost directory named "boost_1_33_1" I 've downloaded, which directories do I have to indicate to the variables INCLUDE and LIB in order to set them? THANK YOU VERY MUCH, David _________________________________________________________________ Retrouvez Windows Live Messenger sur votre mobile ! http://www.messengersurvotremobile.com

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Re: [Boost-users] Boost-users Digest, Vol 1438, Issue 1
by Pavlo Korzhyk 02 Nov '07

02 Nov '07

It is definitely possible given the resources required:) This will be great to have an application server and a set of APIs and tools for C++. At the moment we have most of the libraries, one main gap is OO-persistance, probably implemented as an ORM. I use boost.serialization, it's cool, but it is not enough IMHO: Library I dream about would serialize separate objects and fetch them when needed from one archive. And boost.serialization doesn't provide neither ACID transactions nor iterators over the content of the archive. There is also a lack of "JSP" compiler - but it's not that hard to implement. So all is needed is to implement these two things, then take Apache, cgixx and you have J2EE in C++. And when you have all the bricks - you don't actually need a specification or a ready to use standard, because putting it all together is (looks like) a piece of cake. It's a lot of work, but it's not that much as "mammoth effort" :) PS Correct me if my comments on the current state of the free C++ libraries is wrong. I listed the problems for which I tried but didn't find any ready-to-use solution. So any hints like "take a look at xyz.sourceforge.net" are highly appreciated. > From: Stefan Kok <stefan(a)opensolutions.co.za> > Subject: [Boost-users] C++ & Enterprise Solutions > To: boost-users(a)lists.boost.org > Message-ID: <1193982052.13506.43.camel(a)kobus.opensol.local> > Content-Type: text/plain > > Dear List > > If this is not the correct list to post to. Then please forgive my > ignorance. > > I have been admiring the work of Boost and its contributors for some > time now. My questions / comments : > > 1) Would their be any benefit to the community, developing a > specification for C++ similar to SUN's J2EE and JEE specification ? > > I do realize this would require a mammoth effort as well as commitment > in terms of resources. > > 2) Is it possible to establish such a project under the open source > banner ? > > Given the commitment and resources required. > > 3) Would this be reinventing the wheel ? > > > I know SUN & Java got there first (the J2EE thing). But C++ does have > some very powerful features which makes it unique in some ways, > templates for one. > > WBR, Pavlo Korzhyk ICQ#155870780

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[boost-users] [program options]
by chun ping wang 02 Nov '07

02 Nov '07

HI how would I use program options to accept multiple input. Example I have a diffieHellmanKeyExchange program running through command prompt. // begin main program #include <iostream> #include <boost/tuple/tuple_io.hpp> #include <boost/program_options.hpp> #include "cppdef/BitOperation.cpp" #include "cppdef/mathfunc.cpp" #include "cppdef/IsPrime.cpp" #include "cppdef/DiffieHellman.cpp" #include <BigInteger.hpp> #include <BigIntegerUtils.hpp> int main( int ac, char* av[] ) { namespace po = boost::program_options; po::options_description desc("Allowed options"); boost::tuple<BigInteger, BigInteger> key_pair; desc.add_options() ("generate", "generates a pair of key") ("secert", po::value(&key_pair), "creates the share secret key"); po::variables_map vm; po::store(po::parse_command_line(ac, av, desc), vm); po::notify(vm); if (vm.count("generate")) { BigInteger my_prime = encryptcpw::random_prime<BigInteger>(&algocpw::Miller_Rabin<BigInteger>, 10); std::cout << "my prime: " << my_prime << "\n"; boost::tuple<BigInteger, BigInteger> pare(encryptcpw::dh_init<BigInteger>( my_prime )); std::cout << "pair of generated number: " << pare << "\n"; } if (vm.count("secert")) { const BigInteger p( encryptcpw::random_prime<BigInteger>(&algocpw::Miller_Rabin<BigInteger>, 10)); std::cout << encryptcpw::dh_secret<BigInteger>( p, boost::tuples::get<0>(key_pair), boost::tuples::get<1>(key_pair)); } } // end program The thing compiles but when I do DiffieHellman.exe --secert 817 697 I get this error. C:\CPW\cs_classes>DiffieHellmanEncrypt --secert 817 697 terminate called after throwing an instance of 'boost::program_options::invalid_ option_value' what(): in option 'secert': invalid option value '817' This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information.

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custom formatting the current local date time into a string
by Jeff 02 Nov '07

02 Nov '07

Hello, How can I grab the current local date and time, and format it so that it looks like this: YYYY_MMM_DD_HH_MM_SS ? I can't seem to get the facet stuff to work right. Thanks, Jeff

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[boost-users] [general question] deciding to use member function or not.
by chun ping wang 02 Nov '07

02 Nov '07

Hi is their a simple way *at compile time *to determine if a member function exist for a particular instance, if yes than use that function otherwise do not use it. example std::list<int> li; // check if unique is a member function of li, if yes use unique. li.unique(); // else use stl unique. std::unique(li.begin(), li.end());

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