- Boost-users - lists.boost.org

[multi_index] no non-const reference even for simple sorted container
by Markus Werle 02 Feb '07

02 Feb '07

> Hi! I tried to use multi_index_container as a drop in replacement for std::map and hoped that I could obtain non-const references to the values therein. Although returning a non-const reference might not be a problem for a multi_index_container with only 1 sorting criterium the lib and the compiler insist on const &. Workarounds beyond modify(...) available? Markus #include <boost/tuple/tuple.hpp> #include <boost/multi_index_container.hpp> #include <boost/multi_index/sequenced_index.hpp> #include <boost/multi_index/key_extractors.hpp> #include <boost/multi_index/ordered_index.hpp> #include <string> namespace bm = ::boost::multi_index; // http://lists.boost.org/boost-users/2005/12/16088.php template<typename Tuple,int N> struct tuple_member_extractor { typedef typename boost::tuples::element<N,Tuple>::type result_type; const result_type& operator()(const Tuple& t) const { return boost::tuples::get<N>(t); } }; typedef boost::tuple<std::string, std::string> element; typedef bm::multi_index_container< element, bm::indexed_by<bm::ordered_unique <tuple_member_extractor<element, 0> > > > multi_t; int main() { multi_t test; test.insert(boost::make_tuple("a", "aa")); // will not compile element & ref = test.find("a"); std::string & s = ref.get<1>(); }

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[bind] how to get a funtor of a function since the function's template argument is a functor
by hongleij＠126.com 02 Feb '07

02 Feb '07

// how to get the functor of function caller below,which could be used in a boost::thread or other condition #include <boost/bind.hpp> #include <iostream> class BufferMoniter { public: void maitain() { std::cout <<" BufferMoniter" << std::endl; } }; class LocalPeer { public: template <class T> void caller(unsigned int interval,T t) { //do something t(); } void fork() { BufferMoniter *pBuffer=new BufferMoniter( ); caller(500,boost::bind(&BufferMoniter::maitain,pBuffer)); //I want a functor of it //boost::thread thrd( ); //insert here //thre.join(); } }; //best wishes

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Re: [Boost-users] Serialization of dynamic data
by Pranckevicius, Tadas 02 Feb '07

02 Feb '07

I have just noticed, shouldn't it be ~Dyn() { delete [] data; } -----Original Message----- From: Anders Sundman [mailto:anders.sundman@optonova.se] Sent: 01 February 2007 14:55 To: boost-users(a)lists.boost.org Subject: [Boost-users] Serialization of dynamic data Hi! About the boost::serialization library, what is the best way to handle dynamic data in classes? Any idéas, suggestions or caveats? I didn't manage to find anything about this in the docs. Consider the following sample class: struct Dyn { Dyn(int s) : data(0), size(s) { data = new char[size]; } ~Dyn() { delete data; } char* data; int size; private: friend class boost::serialization::access; template< class Archive > void serialize( Archive &ar, unsigned int ver ) { // -> ar & data; What to do here? ar & size; } }; What to do with the data pointer? Is there any way to determine (in the serialize function) if a serialization or "de-serialization" is taking place? And have different behaviours - either allocating a new char[x] or copying data to the archive? Is there any way to store dynamic data in an archive? Best regards, Anders Sundman _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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[threads] thread_group::create_thread() locks?
by Manuel Jung 02 Feb '07

02 Feb '07

Hi, My program uses a thread group for handling threads. these are joined, when the program ist killed, which should happen not so often, because its used to be a daemon. Most time it works just as expected. but sometimes after running the program for some minutes and after creating a bunch of threads the function thread_group::create_thread() locks. Is this possible? i think it shoulnt lokc, but it does. Im sorry, i cannot show you code cause its closed source and its a liddle bit too big and also works most of the time. I hope a answer to this question will allready help fixing. Thanks for reading. Cheers Manuel Jung

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help with filesystem
by Polder, Matthew J 01 Feb '07

01 Feb '07

Hi, I started using filesystem, regex, and bind today. It's been interesting. I'm using Visual C++ 8.0 on an XP machine that has network filesystems mounted to it, some using letters (H:\, Y:\, etc.), some accessable via two slashes (//linden/temp/, etc). I'd like to peruse these using boost::filesystem. The following works: std::string t = "h:\\temp"; boost::filesystem::path p(t, boost::filesystem::native); but I can't get filesystem to work with the string "h:/temp"; std::string s = p.string(); // s = "h:/temp" bool b = boost::filesystem::portable_posix_name(s); //returns false b = boost::filesystem::windows_name(s); //returns false b = boost::filesystem::portable_name(s); //returns false b = boost::filesystem::portable_directory_name(s); //returns false b = boost::filesystem::portbale_file_name(s); //returns false b = boost::filesystem::native(s); //returns false Also, I'd like to do the following std::string q = "//linden/temp/"; boost::filesystem::path p2(q); Any help is appreciated. thanks, matthew

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help with boost::bind and boost::regex
by Polder, Matthew J 01 Feb '07

01 Feb '07

I am trying to do the following: std::vector< std::string > filenames; //list of filenames retrieved using filesystem boost::regex r(".*txt$"); std::vector< std::string >::const_iterator iter = std::find_if( filenames.begin(), filenames.end(), boost::bind(boost::regex_match, _1, r) ); //Doesn't compile. I'm trying to find strings that match (or don't match) a particular regular expression. Help in properly using boost::bind and negating it would be helpful. thanks, matthew

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Build only static library with -fPIC option.
by Bo Peng 01 Feb '07

01 Feb '07

Dear list, I am building boost cvs. For my specific application, I need to build only static libraries with -fPIC option. I tried command > bjam -j4 --prefix=/usr "-sBUILD=release <runtime-link>static <cxxflags>-fPIC" --with-serialization --with-iostreams install But I still get .a and .so libraries under /usr/lib. I used -n option (an advise I get from one of my previous posts) and the building commands are like: "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -DBOOST_ALL_NO_LIB=1 -DNDEBUG -I"." -c -o "bin.v2/libs/serialization/build/gcc-3.4.6/release/link-static/binary_wiarchive.o" "libs/serialization/src/binary_wiarchive.cpp" so no -fPIC is passed. I tried bjam -h, but get even more confused because I am told.. -n Don't actually execute the updating actions. I guess cvs/bjam handles these options totally differently than boost 1.33.1, but how can I get the latest information? Many thanks in advance. Bo

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[bind] how to get the type after bind
by hongleij＠126.com 01 Feb '07

01 Feb '07

//my question is how to write the type ??? below to make it run . #include <boost/bind.hpp> #include <iostream> using boost::bind; void print() { std::cout <<" print" << std::endl; } template <class T> void func(T t) { std::cout <<"func1(T t) : " ; t(); } int main() { func(bind(&print)); //ok bind ( &func<???>, bind(&print) ) ; //don't know how to write it }

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Re: [Boost-users] [bind] how to get the type after bind
by Nat Goodspeed 01 Feb '07

01 Feb '07

________________________________________ From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of hongleij(a)126.com Sent: Thursday, February 01, 2007 9:00 AM To: boost-users(a)lists.bo... Subject: [Boost-users] [bind] how to get the type after bind //my question is how to write the type ??? below to make it run . #include <boost/bind.hpp> #include <iostream> using boost::bind; void print() { std::cout <<" print" << std::endl; } template <class T> void func(T t) { std::cout <<"func1(T t) : " ; t(); } int main() { func(bind(&print)); //ok bind ( &func<???>, bind(&print) ) ; //don't know how to write it } [Nat] This doesn't directly answer your question; the type produced by bind() is obscure. But would the following suit your need? bind ( &func< boost::function<void ()> >, bind(&print) ) ;

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[boost-thread] why not writ e "sleep" in a better
by hongleij＠126.com 01 Feb '07

01 Feb '07

hi: it really a trouble thing for me to use boost::thread::sleep() : boost::xtime helloworldtime; boost::xtime_get(&helloworldtime, boost::TIME_UTC); helloworldtime.sec += 6; boost::thread::sleep(helloworldtime); i think "boost::thread::sleep(1500) //millisecond " may easy my programming;if have such interface; now i use : void thread_sleep(unsigned int interval) //millisecond { boost::xtime xt; boost::xtime_get(&xt, boost::TIME_UTC); int sec=interval/1000; int msec=interval-1000*sec; xt.nsec += 1000*1000*msec; xt.sec+= sec; boost::thread::sleep(xt); } best wishes;-)

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