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[units] derived_dimension<volume_dimension, 1> units showing as "dimensionless"
by Michael Powell 02 Aug '11

02 Aug '11

Units users, I'm sure this is an include I am missing somewhere. I've got a derived physical dimension defined as derived_dimension<volume_dimension,1>, and the corresponding unit<my_dimension,si::system>, however the to_string() of the quantity shows "dimensionless". I am expecting this should be "m^3"? Regards, Michael

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[units] setting up a derived dimensionless with a custom name/symbol
by Michael Powell 02 Aug '11

02 Aug '11

Boost::Units users, How would we go about setting up a custom unit with its own name/symbol? We would derive another unit that incorporates this one and probably one of the built-in ones. So we might have something like "volume per custom units", or "custom units per time". * From the sounds of things, we would need to setup a custom base unit with its own info struct defining name() and symbol()? * Probably starting out included in the SI system to get the thing working; plausibly extending into other systems/views as we get further along. I'm making an effort to keep our local usages/extensions to the boost::units framework in the same style/structure, so as to keep things flowing well into our application. I am also using meter as a template, but I'm not sure that's quite the template which would get us what we need? Yes, no, maybe? Any insights? Thank you... Regards, Michael

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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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