August 2011 - Boost-users - lists.preview.boost.org

Building boost::posix_time with nano second support
by Matthias Dörfelt 02 Aug '11

02 Aug '11

Hello, I want to use nanoseconds from boost::posix_time but as stated in the reference, you have to define BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG to make that work. Unfortunatelly I don't have any idea where i have to define that variable in the build process. I build boost 1.47.0 like this on osx snow leopard: ./b2 macosx-version=10.6 link=static address-model=32_64 threading=multi stage So, where do I have to define the discussed variable to enable nanosecond support? Offtopic: I also noticed that adress-model=32_64 does not seem to work since all the produced static libs are x86_64 only.- Any ideas about how to fix that? Thank you!

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Delayed/Lazy Function Call
by John M. Dlugosz 02 Aug '11

02 Aug '11

Consider something like this: typedef std::tr1::function<void ()> CapsuleFunc; class worker_thread_queue; class forwarder { worker_thread_queue* queue; const NotifyFunc f; public: forwarder (worker_thread_queue* queue, const NotifyFunc f) : queue(queue), f(f) {} void operator() (uint32_t extended_ID, State_t newstate, State_t oldstate); }; class worker_thread_queue { // doesn't really work, just for illustration public: worker_thread_queue() { // really, would create a thread and thread-safe FIFO } // Calling submit will put f in a queue, and that queue is processed by the // worker thread. It removes each item in FIFO order and executes them. void submit (const CapsuleFunc& f) { /* but it's just an example */ } // Calling wrap will return another function that when executed will call submit(f) on this instance. NotifyFunc wrap (const NotifyFunc& f) { forwarder x (this, f); return x; } }; void forwarder::operator() (uint32_t extended_ID, State_t newstate, State_t oldstate) { CapsuleFunc x= std::tr1::bind (f, extended_ID, newstate, oldstate); queue->submit (x); } // later... worker_thread_queue work_queue; work_queue.wrap(&foo); Presuming a compiler that doesn't have Lambda functions supported, is there some nicer way to acheive the effect shown by 'wrap'? Given a function object f and a object q, I want to create a new function object that when invoked will bind its arguments and call q->submit with the bound-up form. I've seen forwarders throughout Boost; is there a publicly available one that I can use? Or some kind of "delayed apply" that can be called like bind, with the thing to be built up? I recall there is a full heavy duty library for lazy evaluation but don't recall its name. But I'm also wondering if there is a specific (lighter weight or already being used within the Boost libraries I'm already using) mechanism for this. —John

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access violation with asio
by Gianni Ambrosio 02 Aug '11

02 Aug '11

Hi All, can anybody explain me please why I get an access violation in the following code? And why if I enable the std::cout in the stream_handler destructor the code work fine without exception? I'm developing on windows XP, VS 2005. Regards Gianni Here is the code: #include <boost/asio.hpp> #include <boost/bind.hpp> #include <boost/thread.hpp> #include <boost/date_time/posix_time/posix_time_types.hpp> #include <iostream> typedef boost::shared_ptr<boost::asio::ip::tcp::socket> tcp_socket_ptr; class stream_handler { public: stream_handler() : acceptor(io_service) { boost::asio::ip::tcp::endpoint endpoint = boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), 22222); acceptor.open(endpoint.protocol()); acceptor.set_option(boost::asio::ip::tcp::acceptor::reuse_address(true)); acceptor.bind(endpoint); acceptor.listen(); socket = tcp_socket_ptr(new boost::asio::ip::tcp::socket(io_service)); acceptor.async_accept(*socket, boost::bind(&stream_handler::handleAcceptForDebug, this, boost::asio::placeholders::error)); work = boost::shared_ptr<boost::asio::io_service::work>(new boost::asio::io_service::work(io_service)); thread = boost::thread(boost::bind(&boost::asio::io_service::run, &io_service)); } virtual ~stream_handler() { //std::cout << __FUNCTION__ << std::endl; io_service.stop(); } private: boost::asio::io_service io_service; boost::shared_ptr<boost::asio::io_service::work> work; boost::asio::ip::tcp::acceptor acceptor; boost::thread thread; tcp_socket_ptr socket; void handleAcceptForDebug(const boost::system::error_code& iError) {}; }; int main(int argc, char** argv) { stream_handler tcpsocket; return 0; }

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Bizarre problem with range/adaptor/transformed.hpp
by John M. Dlugosz 02 Aug '11

02 Aug '11

I've traced a problem in my program to the inclusion of #include "boost/range/adaptor/transformed.hpp" Nothing is using the features in it (such things are removed from the test case build I'm using to get to the bottom of it). It compiles just as well with or without the line. But if the file is included, the program is broken. If I omit it, then the program works fine. Any suggestions would be welcome.

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boost.regex with ICU memory cleanup on windows
by Alex Perry 02 Aug '11

02 Aug '11

Hi, I recently asked this on stack overflow boost with icu u32_regex memory leak / cache on Win32<http://stackoverflow.com/questions/6867664/boost-with-icu-u32-regex-memory-…> but haven't been able to solve issue yet so thought I would ask here as well. The problem I'm having is that I can't seem to clean up the ICU data when it is loaded by boost regex using the optional icu linkage to support Unicode regex's. I'll copy the example source I posted above:- #define BOOST_TEST_MAIN //Ask boost unit test framework to create a main for us #define BOOST_ALL_DYN_LINK //Ask boost to link to dynamic library rather than purely header support where appropriate #include <boost/test/auto_unit_test.hpp> #include <boost/regex.hpp> #include <boost/regex/icu.hpp> //We use icu extensions to regex to support unicode searches on utf-8 #include <unicode/uclean.h> //We want to be able to clean up ICU cached objects BOOST_AUTO_TEST_CASE( standard_regex ) { boost::regex re( "\\d{3}"); } BOOST_AUTO_TEST_CASE( u32_regex ) { boost::u32regex re( boost::make_u32regex("\\d{3}")); u_cleanup(); //Ask the ICU library to clean up any cached memory } Which may be compiled at command prompt (cl version 16 from vs2010) with appropriate directories inserted if not pathed in on machine. cl test.cpp /I[BOOST HEADERS PATH] /I[ICU HEADERS] /EHsc /MDd -link /LIBPATH:[BOOST LIB PATH] [ICU LIB PATH]icuuc.lib The problem I have with this is that the u_cleanup() does not cleanup so the unit test framework reports memory leaks (at least that is what I think is going on) :- Just compiling the 1st test case will work perfectly - adding in the 2nd test case (with or without the u_cleanup() ) will generate a memory leak report Running 2 test cases... *** No errors detected Detected memory leaks! Dumping objects -> {778} normal block at 0x00668530, 28 bytes long. Data: < 0N W > 00 00 00 00 30 4E C2 57 00 00 00 00 01 00 00 00 {777} normal block at 0x004C5AF8, 14 bytes long. Data: <icudt46l-coll > 69 63 75 64 74 34 36 6C 2D 63 6F 6C 6C 00 {776} normal block at 0x004C5200, 5 bytes long. Data: <root > 72 6F 6F 74 00 {775} normal block at 0x004C9B30, 60 bytes long. Data: < RL ZL > 00 52 4C 00 F8 5A 4C 00 00 00 00 00 00 00 00 00 ... rest removed for clarity As it says in comment on original post icu appears to be loaded as a dynamic link so I can't see why u_cleanup() would not work - alternatively I can't find any calls in boost::regex library which would allow me to ask it to clean up icu cache. Thanks in advance for any help. Alex

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program_options, parse up to first non-option
by Tow Mater 02 Aug '11

02 Aug '11

Can program_options be used to parse command line elements up to the first non-option that is not an option argument?

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Boost::Tokenizer / "string iterators incompatible" error on Visual C++ 2010 Express - runs ok on gcc4.6.0
by asif saeed 02 Aug '11

02 Aug '11

Hi, The following piece of code is giving me "string iterators incompatible" error: ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include <iostream> #include <string> #include <boost/tokenizer.hpp> class Base { public: typedef boost::char_separator<char> sep_type_t; typedef boost::tokenizer<sep_type_t> tokenizer_t; Base(std::string s) : sep_(";"), tok_(s,sep_), i_(tok_.begin()) { } std::string nextToken() { if (i_!=tok_.end()) return *i_++; else return ""; } protected: sep_type_t sep_; tokenizer_t tok_; tokenizer_t::iterator i_; }; class Sub : public Base { public: Sub(std::string s) : Base(s) { std::string t = nextToken(); std::string u = nextToken(); std::string v = nextToken(); } void doSomething() { int x = 0; x +=1; } }; int main (int argc, char **argv) { Sub x("ASIF;Sohail;Kaleem;Maryam;Irfan;Khurram"); x.doSomething(); return 0; } ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// This code is compiling and running fine on GCC 4.6.0 / Fedora 15 / 64-bit. I hope somebody here will help me out on this. Best regards, Asif

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Help with bind usage
by John M. Dlugosz 02 Aug '11

02 Aug '11

Suppose I have something that expects a general function object that takes three parameters. I have a function that takes one parameter, and I don't care about the other two. How do I get an instance func that when called as func(a,b,c) will end up calling my function foo as foo(a) and throw away the other two? If I use bind, I wind up with a functor that takes fewer arguments than the original. But here I have more.

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Article on Boost.Asio in German computer magazine c't
by Boris Schaeling 01 Aug '11

01 Aug '11

I submitted today an article on Boost.Asio which will be published in the German computer magazine c't. I don't know yet in which edition but will tell on http://www.highscore.de/feed.atom. There may be more articles on Boost in c't in the future which I'll announce on my RSS feed then only (not to spam these lists). All of this hopefully helps to increase media coverage of Boost in the longterm. This again could help if for example BoostCon grows into something bigger. For now the article on Boost.Asio is a small step-stone. :) Boris

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[range] range metafunctions and reference types
by Nathan Ridge 01 Aug '11

01 Aug '11

Hello, The range metafunctions currently do not work on range reference types. For example, the following: #include <vector> #include <boost/range/metafunctions.hpp> typedef boost::range_iterator<std::vector<int>&>::type iter_t; Fails with the errors: In file included from lib/boost/boost/range/iterator.hpp:23:0, from lib/boost/boost/range/metafunctions.hpp:18, from test4.cpp:2: lib/boost/boost/mpl/eval_if.hpp: In instantiation of 'boost::mpl::eval_if_c<false, boost::range_const_iterator<std::vector<int>&>, boost::range_mutable_iterator<std::vector<int>&> >': lib/boost/boost/range/iterator.hpp:72:63: instantiated from 'boost::range_iterator<std::vector<int>&>' test4.cpp:4:49: instantiated from here lib/boost/boost/mpl/eval_if.hpp:60:31: error: no type named 'type' in 'boost::mpl::eval_if_c<false, boost::range_const_iterator<std::vector<int>&>, boost::range_mutable_iterator<std::vector<int>&> >::f_ {aka struct boost::range_mutable_iterator<std::vector<int>&>}' This behaviour is OK when you are doing things like this: template <typename Range> typename range_iterator<Range>::type some_function(const Range& r) { ... } because when called with a "const vector<T>&" argument, template argument deduction will deduce "Range" to be just "vector<T>", and this is what we call the metafunction on. Likewise, if some_function has a non-const version that takes a "Range&" argument, it works fine too. But in C++0x, rvalue references allow us to kill two birds with one stone and have just one function that accepts both const and non-const references: template <typename Range> typename range_iterator<Range>::type some_function(Range&& r) { ... } However, the template argument deduction rules for rvalue references are different: if the function is called with a "const vector<T>&" parameter, "Range" will be deduced as "const vector<T>&", i.e. the reference is preserved. But now range_iterator gives an error as indicated above, so we have to do something awkward and verbose like this: template <typename Range> typename range_iterator<typename remove_reference<Range>::type>::type some_function(Range&& r) { ... } Could the range metafunctions be modified to accept range reference parameters and remove the reference themselves? Thanks, Nate.

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[Serialization] Linker error on BOOST_CLASS_EXPORT upgrading from 1.44.0
by Enrico Carrara 01 Aug '11

01 Aug '11

Hello, I am facing a problem with serialization as implemented in Boost 1.47.0 which I did not experience in version 1.44.0. The problem appears as a series of linker errors (Visual C++ 8.0 (VS2005), WinXP 32bit): 1>Compiling... 1>Model_SerializationXml.cpp 1>Model_SerializationTxt.cpp 1>Compiling manifest to resources... 1>Linking... 1>Model_SerializationXml.obj : error LNK2005: "public: static struct boost::archive::detail::extra_detail::guid_initializer<class sm::CompLoad_Test> const & const boost::archive::detail::extra_detail::init_guid<class sm::CompLoad_Test>::g" (?g@?$init_guid@VCompLoad_Test@sm@@@extra_detail@detail@archive@boost @@2ABU?$guid_initializer@VCompLoad_Test@sm@@@2345@B) already defined in Model_SerializationTxt.obj [...many more similar errors] The scenario is as follows: I have a considerable bunch of classes which must be serialized by means of both text and XML archives. To this purpose, I have two compilation units, "Model_SerializationTxt.cpp" and "Model_SerializationXml.cpp", as follows: ///////////////////////////////////////////////// // Model_SerializationTxt.cpp [...] #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/archive_exception.hpp> [...] #include "SerClassExport.h" [...] ///////////////////////////////////////////////// ///////////////////////////////////////////////// // Model_SerializationXml.cpp [...] #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/archive_exception.hpp> [...] #include "SerClassExport.h" [...] ///////////////////////////////////////////////// ///////////////////////////////////////////////// // SerClassExport.h [...] // APPLICATION_DEPENDENT: Include here files // relevant to model classes to be exported // for serialization #include "Model_Root.h" #include "SM/SM_Node.h" [...Many more class definition headers] [...] #include <boost/serialization/export.hpp> // APPLICATION_DEPENDENT: Include here files // relevant to model classes to be exported // for serialization BOOST_CLASS_EXPORT(model::Root) BOOST_CLASS_EXPORT(sm::Node) [...Many more class export definitions] [...] ///////////////////////////////////////////////// The problem seems to be related to the fact that BOOST_CLASS_EXPORT is defined twice in my project. In Boost 1.44.0, struct guid_initializer was defined in "export.hpp" inside an anonymous namespace, while in Boost 1.47.0 - actually, since version 1.45.0 - the definition is inside namespace extra_detail, even if the comment above is unchanged: ///////////////////////////////////////////////// // export.hpp in Boost 1.44.0 [...] // Note INTENTIONAL usage of anonymous namespace in header. // This was made this way so that export.hpp could be included // in other headers. This is still under study. namespace { template<class T> struct guid_initializer [...] #define BOOST_CLASS_EXPORT_IMPLEMENT(T)\ namespace boost {\ namespace archive {\ namespace detail {\ namespace {\ template<>\ struct init_guid< T > {\ static guid_initializer< T > const & g;\ };\ guid_initializer< T > const & init_guid< T >::g =\ ::boost::serialization::singleton<\ guid_initializer< T >\ >::get_mutable_instance().export_guid();\ }}}}\ [...] ///////////////////////////////////////////////// ///////////////////////////////////////////////// // export.hpp in Boost 1.47.0 [...] // Note INTENTIONAL usage of anonymous namespace in header. // This was made this way so that export.hpp could be included // in other headers. This is still under study. namespace extra_detail { template<class T> struct guid_initializer [...] #define BOOST_CLASS_EXPORT_IMPLEMENT(T)\ namespace boost {\ namespace archive {\ namespace detail {\ namespace extra_detail {\ template<>\ struct init_guid< T > {\ static guid_initializer< T > const & g;\ };\ guid_initializer< T > const & init_guid< T >::g =\ ::boost::serialization::singleton<\ guid_initializer< T >\ >::get_mutable_instance().export_guid();\ }}}}\ [...] ///////////////////////////////////////////////// I guess that this might have a role in originating the linker problem. How can I avoid this error? I already tried including the list of BOOST_CLASS_EXPORT only once, i.e in Model_SerializationTxt.cpp only. This solved the linker problem, but serialization of data in XML was then impossible (runtime error). Unfortunately, merging the two compilation units in one is not possible, because the compiler (Visual C++ 8.0) goes out of memory while compiling the big unit (process memory grows beyond 2GB). Is there, in your opinion, a solution or a workaround to this situation? Let me apologize for the very long mail, I did not succeed in shortening it further. Looking forward to any possible advice, thank you in advance for your attention. Enrico

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Boost::Tokenizer - "string iterators incompatible"
by asif saeed 01 Aug '11

01 Aug '11

Hi, The following piece of code is giving me "string iterators incompatible" error: ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include <iostream> #include <string> #include <boost/tokenizer.hpp> class Base { public: typedef boost::char_separator<char> sep_type_t; typedef boost::tokenizer<sep_type_t> tokenizer_t; Base(std::string s) : sep_(";"), tok_(s,sep_), i_(tok_.begin()) { } std::string nextToken() { if (i_!=tok_.end()) return *i_++; else return ""; } protected: sep_type_t sep_; tokenizer_t tok_; tokenizer_t::iterator i_; }; class Sub : public Base { public: Sub(std::string s) : Base(s) { std::string t = nextToken(); std::string u = nextToken(); std::string v = nextToken(); } void doSomething() { int x = 0; x +=1; } }; int main (int argc, char **argv) { Sub x("ASIF;Sohail;Kaleem;Maryam;Irfan;Khurram"); x.doSomething(); return 0; } ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// This code is compiling and running fine on GCC 4.6.0 / Fedora 15 / 64-bit. I hope somebody here will help me out on this. Best regards, Asif

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[units] How to multiply a quantity with a dimensionless factor
by Marcel 01 Aug '11

01 Aug '11

Hi, I'm new to boost and units and hope this is not too trivial. If I try to multiply a quantity with a dimensionless factor like quantity<length> a; quantity<length> b = 2.0 * b; I get compiler errors due to missing operator*. So I worked around this by using quantity<length> b = quantity<dimensionless>(2.0) * b; But I'm wondering if there is a easier and better readable way to do this? Thank you in advance, Marcel

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Execution problem moving libraries
by Alessandro Candini 01 Aug '11

01 Aug '11

Hi everyone. I get a very tricky error with boost.thread. I can compile and execute perfectly a C++ program with the following comand line: g++ -Wall -fPIC -pedantic -g -O3 -DDEBUG -march=native -std=c++0x -lboost_thread -o myExecutable myExecutable.cpp But I have to move this software into another machine, and I thought it was possible to take dynamic libraries with it, in order to properly link them to the executable. I have a structure like the following: package | bin |- myExecutable etc |- libboost_thread.a |- libboost_thread.so -> libbost_thread.so.1.42.0 `- libboost_thread.so.1.42.0 And performing a proper export of LD_LIBRARY_PATH, it seems I obtain a correct link: ldd myExecutable ... libboost_thread.so.1.42.0 => ../etc/libboost_thread.so.1.42.0 (0x002cd000) ... But when I try to execute my software, I obtain the following error: /home/user/myExecutable symbol lookup error: /home/user/myExecutable: undefined symbol: _ZTIN10__cxxabiv115__forced_unwindE Do you have an idea of why this occurs? Have I to compile boost libraries in an uncommon way to make this situation work? Thank you. -- Alessandro Candini MEEO S.r.l. Via Saragat 9 I-44122 Ferrara, Italy Tel: +39 0532 1861501 Fax: +39 0532 1861637 http://www.meeo.it ======================================== "ATTENZIONE:le informazioni contenute in questo messaggio sono da considerarsi confidenziali ed il loro utilizzo è riservato unicamente al destinatario sopra indicato. Chi dovesse ricevere questo messaggio per errore è tenuto ad informare il mittente ed a rimuoverlo definitivamente da ogni supporto elettronico o cartaceo." "WARNING:This message contains confidential and/or proprietary information which may be subject to privilege or immunity and which is intended for use of its addressee only. Should you receive this message in error, you are kindly requested to inform the sender and to definitively remove it from any paper or electronic format."

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[interprocess] garbage chars when extending interprocess strings?
by Anthony Foiani 01 Aug '11

01 Aug '11

I'm having a peculiar problem with interprocess strings. 0. Create the shared string type. typedef boost::interprocess::managed_shared_memory ShmManagerType; typedef char ShmCharType; typedef boost::interprocess::allocator< ShmCharType, ShmManagerType::segment_manager > ShmCharAllocatorType; typedef boost::interprocess::basic_string< ShmCharType, std::char_traits< ShmCharType >, ShmCharAllocatorType > ShmStringType; 1. Initial write succeeds. ShmStringType val; val = "x"; cout << quoteString( x ) << endl; // prints "x" as expected 2. When I overwrite the value with a longer value, the longer value is stored and the length is updated -- but a null character (\0) is inserted at the *old* length. ShmStringType x3( "xxx" ); val = x3; cout << quoteString( val ) << endl; // prints "x\0x" !!! 3. When I write the longer value again, it is stored correctly and there is no \0 in the middle of the string. val = x3; cout << quoteString( val ) << endl; // prints "xxx" as expected 4. The same thing happens if we try a longer value again: ShmStringType x5( "xxxxx" ); val = x5; cout << quoteString( val ) << endl; // prints "xxx\0x" val = x5 cout << quoteString( val ) << endl; // prints "xxxxx" Does this ring bells for anyone? On my embedded platform, I'm using: powerpc e300c3 Linux 2.6.36 eglibc 2.13 boost 1_44_0 g++ 4.5.1 And on my development workstation: intel x86-64 Linux 2.6.35.13-92.fc14 glibc 2.13-1 boost 1.44.0-8.fc14 gcc 4.5.1-4.fc14 Testing this on my development workstation, I see similar issues (although it's not always \0; in this case, I'm getting \xC0 junk characters. Odd!) Test case at: http://foiani.com/cpp/boost/InterProcStringTest.cpp Sample output: http://foiani.com/cpp/boost/ipst-out-ppc32.txt http://foiani.com/cpp/boost/ipst-out-x86_64.txt The output isn't the same: some cases work on one platform but not the other, and the garbage character introduced isn't always \0. Any ideas would be welcome. Testing with a more current boost is a bit problematic; if someone believes that it's been fixed in the mean time, I'll do my best to try with a modern boost. In the mean time, I'll just write the values twice, I guess. :) Thanks for your time and attention! Best regards, Tony

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[Iterator]Can dereference() in iterator_adaptor return a temporary value?
by Remi 01 Aug '11

01 Aug '11

Hi, I'd like a const iterator that acts as a proxy by giving access to elements of type A as if they were elements of unrelated type B. In that case I guess the dereference() member function should return a temporary value, right? Would that be a correct implementation of the idea? Here I just want to access an array of SourceVertexType as if it were an array of VertexType. template<class VertexType> class ConstVerticesIterator : public boost::iterator_adaptor< ConstVerticesIterator<VertexType>, const SourceVertexType*, const VertexType > { private: friend class boost::iterator_core_access; VertexType dereference() const { const SourceVertexType& source_vertex( *base() ); return VertexType( source_vertex.x, source_vertex.y ); } public: explicit ConstVerticesIterator( const SourceVertexType* vertices ) : boost::iterator_adaptor< ConstVerticesIterator<VertexType>, const SourceVertexType*, const VertexType >( vertices ) {} };

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translate C-code into objects
by Peter Foelsche 01 Aug '11

01 Aug '11

Dear All, I would like to translate some C-Code into objects. I did this already for functions and expressions: Writing template functions and passing my expression object as an argument. Now I want to do this for C-Code, which uses if-statements and variables. To do this, I would implement some template function for an if-statement. And some function for an assignment to a variable. Probably using enumerations to indicate the variable. Is this the right approach? Peter

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