March 2014 - Boost-users - lists.preview.boost.org

error with static assert and floating-point detection
by Philipp Kraus 11 Mar '14

11 Mar '14

Hello, I try to use Boost Static Assert to define a template parameter only for double & floats. I use the call BOOST_STATIC_ASSERT( !boost::is_integral<T>::value ) I get in a class the error: error: no member named 'is_integral' in namespace 'boost' BOOST_STATIC_ASSERT( !boost::is_integral<T>::value ) My question is, how can I check the template parameter so that only floating-point types are allowed? How can I avoid the error? Thanks Phil

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boost::asio::io_service::poll_once vs EPOLLET
by Jason Aubrey 11 Mar '14

11 Mar '14

The conditional define of boost::asio::io_service that uses epoll always seems to use edge triggered (ET) flag instead of level triggered (LT). This makes me think poll_once should be avoided due to Scenario 1 below. Can anyone confirm this? Given: 1) 2 sockets (A and B) added to epoll interface for receiving only 2) 2 UDP messages arrive in the same moment on socket A 3) epoll_wait returns a ready socket (socket A) Scenario 1: Using ET with poll_once: 4) If io_service::poll_once is called 1 of 2 messages are read 5) epoll_wait(ET) blocks until another message is received Result: Bad, starvation if another message is not received Scenario 2: Using ET with poll: 4) If io_service::poll is called 2 of 2 messages are read 5) epoll_wait(ET) blocks until another message is received? Result: Good, all messages processed without A/B fairness (unfair since read was greedy) Scenario 3: Using LT with poll_once: 4) If io_service::poll_once is called 1 of 2 messages are read 5) epoll_wait(LT) returns a ready socket (socket A) 6) If io_service::poll_once is called 1 of 1 messages are read Result: Good, all messages processed with A/B fairness I don't think Scenario 3 is currently supported by boost::asio::io_service. Jason

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[Serialization] Avoiding multiple de-serialization
by beet 11 Mar '14

11 Mar '14

Dear Boost-Community, I have a large, "directed" tree-like data structure (i.e., no cycles), holding boost::shared_ptr's either to container-objects or "leaf-objects", i.e. individual objects not holding other objects. All shared_ptr's hold base-pointers, i.e. the leaf-objects share a common base type, but not much else. I would now like to collect statistics on some of the leaf-objects during the program run. In order to do this, I'm storing boost::shared_ptr's to the leaf objects in a container outside of the tree. Getting access to the leaf objects would otherwise be very inefficient, as the tree can have virtually any geometry (except for cycles), and I do not know the geometry in advance. The tree is repeatedly (de-)serialized, and I would like to also (de-)serialize the top-level container, so I still have easy access to the leaf-objects after de-serialization. However, it is not clear to me what happens to the leaf-objects after de-serialization of both the tree and the external container. Will the leaf-objects be de-serialized twice ? Or might there be different leaf-objects in the external container and in the tree ? Thanks for any insight you may provide. Best Regards, beet

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Composer issue with boost::log::sinks::event_log on VS2010
by Konrad Rybacki 11 Mar '14

11 Mar '14

Hello, I use basic_event_log_backend according to documentation<http://www.boost.org/doc/libs/1_55_0/libs/log/doc/html/log/detailed/sink_ba…>- I add formatters to events with event_composer: sinks::event_log::event_composer composer( sinks::event_log::direct_event_id_mapping<int>("EventId") ); composer[MSG1] % expr::attr<WORD>("Tag1"); composer[MSG2] % expr::attr<DWORD>("Tag2"); composer[MSG3] % expr::attr<std::string>("Tag3"); backend->set_event_composer(composer); Unfortunately event log entries in event viewer are incomplete - i.e. there are still "%n" placeholders instead of their values. From what I have found while inspecting the code with debugger it seems that event_map_reference& operator% (FormatterT const& fmt)is never hit - so m_EventMap in composer is empty. I added a method that works the same way as mentioned operator: template< typename FormatterT > event_map_reference& add_formatter(FormatterT const &fmt) { m_Composer = m_Owner.add_formatter(m_ID, m_Composer, formatter_type(fmt)); return *this; } and call it explicitly, so the code looks like that: composer[MSG1].add_formatter(expr::attr<WORD>("Tag1")); composer[MSG2].add_formatter(expr::attr<DWORD>("Tag2")); composer[MSG3].add_formatter(expr::attr<std::string>("Tag3")); Now m_EventMap has three items - and I get empty strings instead of "%n" in event viewer. I pass the tag values with boost macro, i.e.: BOOST_LOG_SCOPED_THREAD_TAG("Tag3", std::string("value")); I am using Visual Studio 2010 compiler. Any ideas? Regards, Konrad.

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Customizing locale of stream for Boost.Serialization seems to fail
by Christophe Fuzier 11 Mar '14

11 Mar '14

Hi, I have a problem with Boost.Serialization. I have posted a question on a forum but have not got any answer until now. Here is the reproduction of my post (note: I'm using Boost 1.48, patch level 0). I need to use Boost.Serialization to serialize floating-point numbers. Since NaN and infinites cannot natively be read from an input stream, I am trying to use the facets in boost/math/special_functions. I have tested them on my platform using code similar to the examples we can find here: http://www.boost.org/doc/libs/1_50_0/libs/math/doc/sf_and_dist/html/math_to… However, the following code still fails to properly unserialize non-finite floating point values (an exception is thrown with description "input stream error"). #include <limits> #include <locale> #include <sstream> #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/math/special_functions/nonfinite_num_facets.hpp> #include <boost/serialization/nvp.hpp> struct Data { float f; Data() : f(std::numeric_limits<float>::quiet_NaN()) {} template <class Archive> void serialize(Archive & ar, unsigned const) { ar & BOOST_SERIALIZATION_NVP(f); } }; void test() { using namespace boost::archive; Data d; std::ostringstream oss; xml_oarchive oar(oss); oar << BOOST_SERIALIZATION_NVP(d); //std::cout << oss.str() << std::endl; std::istringstream iss(oss.str()); std::locale const new_loc(iss.getloc(), new boost::math::nonfinite_num_get<char>); iss.imbue(new_loc); xml_iarchive iar(iss); iar >> BOOST_SERIALIZATION_NVP(d); std::cout << d.f << std::endl; } Am I doing something wrong? Is there a problem with my Boost version or my platform? Is there a better solution? Any help would be greatly appreciated. <END OF POST> Thank you in advance for any suggestion. Christophe Fuzier

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Re: [Boost-users] Problems with Boost 1.41
by Ксения Сафина 10 Mar '14

10 Mar '14

Thank you, Ben My platform is x86_64. I have any experience with Boost and c++ language at all so I'm sorry for asking questions like this. The errors like "Threading support unavaliable: it has been explicitly disabled with BOOST_DISABLE_THREADS" are not clear for me. I mean I have any ideas about where do they come from. gcc -v gives me "Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.7.3-1ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs --enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.7 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --with-system-zlib --enable-objc-gc --with-cloog --enable-cloog-backend=ppl --disable-cloog-version-check --disable-ppl-version-check --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-1ubuntu1) " Is there something wrong with these options? Ksenia > >Date: Mon, 10 Mar 2014 11:42:02 +0800 >From: Ben Pope < benpope81(a)gmail.com > >To: boost-users(a)lists.boost.org >Subject: Re: [Boost-users] Problems with Boost 1.41 >Message-ID: < lfjcb4$kvb$1(a)ger.gmane.org > >Content-Type: text/plain; charset=UTF-8; format=flowed > >On Sunday, March 09, 2014 06:05 PM, ?????? ?????? wrote: >> Hi everyone, >> >> I'm trying to build this >> http://vina.scripps.edu/manual.html#build program using Boost 1.41. >> >> 'make' command gives me a large amount of errors: > >snip > >> error: #error >> "Threading support unavaliable: it has been explicitly disabled with >> BOOST_DISABLE_THREADS" > >snip > >> error: #error >> "Sorry, no boost threads are available for this platform." > >snip > >> Could anyone help me to understand what do these all errors mean? > >I think the error messages are quite clear. > >> I'm on Ubuntu 13.04, gcc version is 4.7.3 (Ubuntu/Linaro 4.7.3-1ubuntu1) > >I hesitate to ask, but what architecture is your platform? > >Boost 1.41 was tested with gcc 4.4.1 on Ubuntu (and some older >compilers), the platform is not mentioned, but it's probably x86 or >x86_64. It's possible that you need to modify the compiler >configuration to accept the newer gcc and/or libstdc++. > >Ben > >Date: Sun, 09 Mar 2014 14:05:41 +0400 >From: ?????? ?????? < cat7mail.ru(a)mail.ru > >To: boost-users(a)lists.boost.org >Subject: [Boost-users] Problems with Boost 1.41 >Message-ID: < 1394359541.299650432(a)f329.i.mail.ru > >Content-Type: text/plain; charset="utf-8" > > Hi everyone, > >I'm trying to build this http://vina.scripps.edu/manual.html#build ?program using Boost 1.41. > >'make' ?command gives me a large amount of errors: >? >noraneko@noraneko-K53SJ:~/Programs/autodock_vina_1_1_2/build/linux/release$ make/usr/bin/g++ -static -pthread -ansi -Wno-long-long -O3 -DNDEBUG -I /usr/local/include -I ../../../src/lib -o main.o -c ../../../src/main/main.cpp >In file included from /usr/local/include/boost/thread/detail/platform.hpp:17:0, >from /usr/local/include/boost/thread/thread.hpp:12, >from ../../../src/main/main.cpp:32: >/usr/local/include/boost/config/requires_threads.hpp:29:4: error: #error "Threading support unavaliable: it has been explicitly disabled with BOOST_DISABLE_THREADS" >In file included from /usr/local/include/boost/thread/thread.hpp:12:0, >from ../../../src/main/main.cpp:32: >/usr/local/include/boost/thread/detail/platform.hpp:67:9: error: #error "Sorry, no boost threads are available for this platform." >In file included from ../../../src/main/main.cpp:32:0: >/usr/local/include/boost/thread/thread.hpp:19:2: error: #error "Boost threads unavailable on this platform" >In file included from /usr/local/include/boost/thread/detail/thread.hpp:11:0, >from /usr/local/include/boost/thread/thread.hpp:22, >from ../../../src/main/main.cpp:32: >/usr/local/include/boost/thread/mutex.hpp:18:2: error: #error "Boost threads unavailable on this platform" >In file included from /usr/local/include/boost/thread/detail/thread.hpp:13:0, >from /usr/local/include/boost/thread/thread.hpp:22, >from ../../../src/main/main.cpp:32: >/usr/local/include/boost/thread/detail/thread_heap_alloc.hpp:19:2: error: #error "Boost threads unavailable on this platform" >In file included from /usr/local/include/boost/thread/detail/thread_group.hpp:9:0, >from /usr/local/include/boost/thread/thread.hpp:24, >from ../../../src/main/main.cpp:32: >/usr/local/include/boost/thread/shared_mutex.hpp:18:2: error: #error "Boost threads unavailable on this platform" >In file included from /usr/local/include/boost/thread/thread.hpp:22:0, >from ../../../src/main/main.cpp:32: >/usr/local/include/boost/thread/detail/thread.hpp:40:9: error: expected class-name before ?{? token >/usr/local/include/boost/thread/detail/thread.hpp:68:9: error: expected class-name before ?{? token >/usr/local/include/boost/thread/detail/thread.hpp:88:9: error: expected class-name before ?{? token >/usr/local/include/boost/thread/detail/thread.hpp:113:17: error: ?mutex? in namespace ?boost? does not name a type >/usr/local/include/boost/thread/detail/thread.hpp:114:9: error: ?thread_data_ptr? in namespace ?boost::detail? does not name a type >/usr/local/include/boost/thread/detail/thread.hpp:118:49: error: expected ?)? before ?data? >/usr/local/include/boost/thread/detail/thread.hpp:120:9: error: ?thread_data_ptr? in namespace ?boost::detail? does not name a type >In file included from /usr/local/include/boost/thread/thread.hpp:22:0, >from ../../../src/main/main.cpp:32: >/usr/local/include/boost/thread/detail/thread.hpp:134:23: error: ?thread_data_ptr? in namespace ?boost::detail? does not name a type >/usr/local/include/boost/thread/detail/thread.hpp:139:23: error: ?thread_data_ptr? in namespace ?boost::detail? does not name a type >/usr/local/include/boost/thread/detail/thread.hpp:319:17: error: ?thread_data_base? in namespace ?boost::detail? does not name a type >/usr/local/include/boost/thread/detail/thread.hpp:320:9: error: ?native_handle_type? does not name a type >/usr/local/include/boost/thread/detail/thread.hpp: In constructor ?boost::thread::thread(F, typename boost::disable_if<boost::is_convertible<T&, boost::detail::thread_move_t<T> >, boost::thread::dummy*>::type)?: >/usr/local/include/boost/thread/detail/thread.hpp:189:13: error: class ?boost::thread? does not have any field named ?thread_info? >/usr/local/include/boost/thread/detail/thread.hpp: In constructor ?boost::thread::thread(boost::detail::thread_move_t<T>)?: >/usr/local/include/boost/thread/detail/thread.hpp:197:13: error: class ?boost::thread? does not have any field named ?thread_info? >/usr/local/include/boost/thread/detail/thread.hpp: In constructor ?boost::thread::thread(boost::detail::thread_move_t<boost::thread>)?: >/usr/local/include/boost/thread/detail/thread.hpp:204:13: error: ?thread_info? was not declared in this scope >/usr/local/include/boost/thread/detail/thread.hpp:204:28: error: ?class boost::thread? has no member named ?thread_info? >/usr/local/include/boost/thread/detail/thread.hpp:205:16: error: ?class boost::thread? has no member named ?thread_info? >/usr/local/include/boost/thread/detail/thread.hpp: In constructor ?boost::thread::thread(F, A1)?: >/usr/local/include/boost/thread/detail/thread.hpp:237:13: error: class ?boost::thread? does not have any field named ?thread_info? >/usr/local/include/boost/thread/detail/thread.hpp: In constructor ?boost::thread::thread(F, A1, A2)?: >/usr/local/include/boost/thread/detail/thread.hpp:243:13: error: class ?boost::thread? does not have any field named ?thread_info? >/usr/local/include/boost/thread/detail/thread.hpp: In constructor ?boost::thread::thread(F, A1, A2, A3)?: >/usr/local/include/boost/thread/detail/thread.hpp:250:13: error: class ?boost::thread? does not have any field named ?thread_info? >.... >/usr/local/include/boost/thread/detail/thread_group.hpp: In member function ?void boost::thread_group::remove_thread(boost::thread*)?: >/usr/local/include/boost/thread/detail/thread_group.hpp:55:13: error: ?lock_guard? is not a member of ?boost? >/usr/local/include/boost/thread/detail/thread_group.hpp:55:31: error: ?shared_mutex? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp:55:51: error: ?m? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp:55:52: error: ?guard? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp: In member function ?void boost::thread_group::join_all()?: >/usr/local/include/boost/thread/detail/thread_group.hpp:65:13: error: ?shared_lock? is not a member of ?boost? >/usr/local/include/boost/thread/detail/thread_group.hpp:65:32: error: ?shared_mutex? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp:65:52: error: ?m? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp:65:53: error: ?guard? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp: In member function ?void boost::thread_group::interrupt_all()?: >/usr/local/include/boost/thread/detail/thread_group.hpp:77:13: error: ?shared_lock? is not a member of ?boost? >/usr/local/include/boost/thread/detail/thread_group.hpp:77:32: error: ?shared_mutex? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp:77:52: error: ?m? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp:77:53: error: ?guard? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp: In member function ?size_t boost::thread_group::size() const?: >/usr/local/include/boost/thread/detail/thread_group.hpp:89:13: error: ?shared_lock? is not a member of ?boost? >/usr/local/include/boost/thread/detail/thread_group.hpp:89:32: error: ?shared_mutex? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp:89:52: error: ?m? was not declared in this scope >/usr/local/include/boost/thread/detail/thread_group.hpp:89:53: error: ?guard? was not declared in this scope >make: *** [main.o] Error 1 > >Could anyone help me to understand what do these all errors mean?? > >I'm on Ubuntu 13.04, gcc version is 4.7.3 (Ubuntu/Linaro 4.7.3-1ubuntu1)? > >Ksenia

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Problems with Boost 1.41
by Ксения Сафина 10 Mar '14

10 Mar '14

Hi everyone, I'm trying to build this http://vina.scripps.edu/manual.html#build program using Boost 1.41. 'make' command gives me a large amount of errors: noraneko@noraneko-K53SJ:~/Programs/autodock_vina_1_1_2/build/linux/release$ make/usr/bin/g++ -static -pthread -ansi -Wno-long-long -O3 -DNDEBUG -I /usr/local/include -I ../../../src/lib -o main.o -c ../../../src/main/main.cpp In file included from /usr/local/include/boost/thread/detail/platform.hpp:17:0, from /usr/local/include/boost/thread/thread.hpp:12, from ../../../src/main/main.cpp:32: /usr/local/include/boost/config/requires_threads.hpp:29:4: error: #error "Threading support unavaliable: it has been explicitly disabled with BOOST_DISABLE_THREADS" In file included from /usr/local/include/boost/thread/thread.hpp:12:0, from ../../../src/main/main.cpp:32: /usr/local/include/boost/thread/detail/platform.hpp:67:9: error: #error "Sorry, no boost threads are available for this platform." In file included from ../../../src/main/main.cpp:32:0: /usr/local/include/boost/thread/thread.hpp:19:2: error: #error "Boost threads unavailable on this platform" In file included from /usr/local/include/boost/thread/detail/thread.hpp:11:0, from /usr/local/include/boost/thread/thread.hpp:22, from ../../../src/main/main.cpp:32: /usr/local/include/boost/thread/mutex.hpp:18:2: error: #error "Boost threads unavailable on this platform" In file included from /usr/local/include/boost/thread/detail/thread.hpp:13:0, from /usr/local/include/boost/thread/thread.hpp:22, from ../../../src/main/main.cpp:32: /usr/local/include/boost/thread/detail/thread_heap_alloc.hpp:19:2: error: #error "Boost threads unavailable on this platform" In file included from /usr/local/include/boost/thread/detail/thread_group.hpp:9:0, from /usr/local/include/boost/thread/thread.hpp:24, from ../../../src/main/main.cpp:32: /usr/local/include/boost/thread/shared_mutex.hpp:18:2: error: #error "Boost threads unavailable on this platform" In file included from /usr/local/include/boost/thread/thread.hpp:22:0, from ../../../src/main/main.cpp:32: /usr/local/include/boost/thread/detail/thread.hpp:40:9: error: expected class-name before ‘{’ token /usr/local/include/boost/thread/detail/thread.hpp:68:9: error: expected class-name before ‘{’ token /usr/local/include/boost/thread/detail/thread.hpp:88:9: error: expected class-name before ‘{’ token /usr/local/include/boost/thread/detail/thread.hpp:113:17: error: ‘mutex’ in namespace ‘boost’ does not name a type /usr/local/include/boost/thread/detail/thread.hpp:114:9: error: ‘thread_data_ptr’ in namespace ‘boost::detail’ does not name a type /usr/local/include/boost/thread/detail/thread.hpp:118:49: error: expected ‘)’ before ‘data’ /usr/local/include/boost/thread/detail/thread.hpp:120:9: error: ‘thread_data_ptr’ in namespace ‘boost::detail’ does not name a type In file included from /usr/local/include/boost/thread/thread.hpp:22:0, from ../../../src/main/main.cpp:32: /usr/local/include/boost/thread/detail/thread.hpp:134:23: error: ‘thread_data_ptr’ in namespace ‘boost::detail’ does not name a type /usr/local/include/boost/thread/detail/thread.hpp:139:23: error: ‘thread_data_ptr’ in namespace ‘boost::detail’ does not name a type /usr/local/include/boost/thread/detail/thread.hpp:319:17: error: ‘thread_data_base’ in namespace ‘boost::detail’ does not name a type /usr/local/include/boost/thread/detail/thread.hpp:320:9: error: ‘native_handle_type’ does not name a type /usr/local/include/boost/thread/detail/thread.hpp: In constructor ‘boost::thread::thread(F, typename boost::disable_if<boost::is_convertible<T&, boost::detail::thread_move_t<T> >, boost::thread::dummy*>::type)’: /usr/local/include/boost/thread/detail/thread.hpp:189:13: error: class ‘boost::thread’ does not have any field named ‘thread_info’ /usr/local/include/boost/thread/detail/thread.hpp: In constructor ‘boost::thread::thread(boost::detail::thread_move_t<T>)’: /usr/local/include/boost/thread/detail/thread.hpp:197:13: error: class ‘boost::thread’ does not have any field named ‘thread_info’ /usr/local/include/boost/thread/detail/thread.hpp: In constructor ‘boost::thread::thread(boost::detail::thread_move_t<boost::thread>)’: /usr/local/include/boost/thread/detail/thread.hpp:204:13: error: ‘thread_info’ was not declared in this scope /usr/local/include/boost/thread/detail/thread.hpp:204:28: error: ‘class boost::thread’ has no member named ‘thread_info’ /usr/local/include/boost/thread/detail/thread.hpp:205:16: error: ‘class boost::thread’ has no member named ‘thread_info’ /usr/local/include/boost/thread/detail/thread.hpp: In constructor ‘boost::thread::thread(F, A1)’: /usr/local/include/boost/thread/detail/thread.hpp:237:13: error: class ‘boost::thread’ does not have any field named ‘thread_info’ /usr/local/include/boost/thread/detail/thread.hpp: In constructor ‘boost::thread::thread(F, A1, A2)’: /usr/local/include/boost/thread/detail/thread.hpp:243:13: error: class ‘boost::thread’ does not have any field named ‘thread_info’ /usr/local/include/boost/thread/detail/thread.hpp: In constructor ‘boost::thread::thread(F, A1, A2, A3)’: /usr/local/include/boost/thread/detail/thread.hpp:250:13: error: class ‘boost::thread’ does not have any field named ‘thread_info’ .... /usr/local/include/boost/thread/detail/thread_group.hpp: In member function ‘void boost::thread_group::remove_thread(boost::thread*)’: /usr/local/include/boost/thread/detail/thread_group.hpp:55:13: error: ‘lock_guard’ is not a member of ‘boost’ /usr/local/include/boost/thread/detail/thread_group.hpp:55:31: error: ‘shared_mutex’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp:55:51: error: ‘m’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp:55:52: error: ‘guard’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp: In member function ‘void boost::thread_group::join_all()’: /usr/local/include/boost/thread/detail/thread_group.hpp:65:13: error: ‘shared_lock’ is not a member of ‘boost’ /usr/local/include/boost/thread/detail/thread_group.hpp:65:32: error: ‘shared_mutex’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp:65:52: error: ‘m’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp:65:53: error: ‘guard’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp: In member function ‘void boost::thread_group::interrupt_all()’: /usr/local/include/boost/thread/detail/thread_group.hpp:77:13: error: ‘shared_lock’ is not a member of ‘boost’ /usr/local/include/boost/thread/detail/thread_group.hpp:77:32: error: ‘shared_mutex’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp:77:52: error: ‘m’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp:77:53: error: ‘guard’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp: In member function ‘size_t boost::thread_group::size() const’: /usr/local/include/boost/thread/detail/thread_group.hpp:89:13: error: ‘shared_lock’ is not a member of ‘boost’ /usr/local/include/boost/thread/detail/thread_group.hpp:89:32: error: ‘shared_mutex’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp:89:52: error: ‘m’ was not declared in this scope /usr/local/include/boost/thread/detail/thread_group.hpp:89:53: error: ‘guard’ was not declared in this scope make: *** [main.o] Error 1 Could anyone help me to understand what do these all errors mean? I'm on Ubuntu 13.04, gcc version is 4.7.3 (Ubuntu/Linaro 4.7.3-1ubuntu1) Ksenia

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[boost::thread] Starting thread at specific time
by Kyle Ketterer 09 Mar '14

09 Mar '14

Hello all, I am working on an application which I originally wrote as a console app and am now transforming into a Windows service. Basically, looking for a little advice. My goal is to have an independent service which starts at a specific time and only runs for a set amount of hours. The code I am currently contemplating looks like this: ---------------------------------------------------------------- int start_hour = 18; //6pm time_t t = time(0); //current time struct tm* now = localtime ( &t ); //total time the app should run for boost::posix_time::time_duration run_duration ( 10, 0, 0, 0 ); //current time relative duration boost::posix_time::time_duration start_duration ( now->tm_hour, now->tm_min, now->tm_sec ); //get duration until service start boost::posix_time::time_duration diff = boost::posix_time::hours(start_hour) - boost::posix_time::milliseconds (start_duration.total_milliseconds() ); //dont start thread until designated start time boost::thread thr ( &ServiceWorkerThread ); //sleep this thread until ready to start boost::this_thread::sleep( boost::posix_time::milliseconds( diff.total_milliseconds() ) ); if ( thr.timed_join( run_duration ) ) { //do stuff } ------------------------------------------------------------- Basically, I am trying to make use of the time_duration class to achieve this. Based on the code above, I want to run the service for 10 hours, but not start it until the correct hour. Somewhere near the end of the service entry I will restart the service and the service *should* until the correct time and only execute for X hours. I am looking for further suggestions/improvements based on the above. Thanks!

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boost::geometry::index::rtree with different CoordinateSystem
by Ola Martin Lykkja 08 Mar '14

08 Mar '14

Hi, I am trying to build a rtree index with a collection if waypoint (about 30.000) each represented by longitude and latitude. When I use Cartesian coordinates rtree.query works as expected. However the results are slightly wrong because of my use of longitude,latitude in the cartesian domain. I then tried to refine the datatypes to use spherical_equatorial and geographic CoordinateSystem. Now I encounter two problems: a) With geographic, it does not compile. b) With spherical_equatorial query(nearest) gives clearly wrong results. Do you have any clues on what I am doing wrong? Attached is two images illustrating the query results. Search target is dot with label on it. I am using boost 1.55.0 on Linux with g++ 4.4.3 (same result with 4.6.3). typedef bg::model::point<double, 2, bg::cs::cartesian> geo_point; typedef bg::model::point<double, 2, bg::cs::spherical_equatorial<bg::degree> > geo_point_with_wrong_results; typedef bg::model::point<double, 2, bg::cs::geographic<bg::degree> > geo_point_does_not_compile; typedef std::pair<geo_point, unsigned int> geo_vg_value; void test() { iterate_over_all_waypoints (wp) { geo_point pt(wp->on, wp->lat); rtree.insert(std::make_pair(pt, wp->id)); } std::vector<geo_vg_value> result; geo_point here(targetLat, targetLat); rtree.query(bgi::nearest(here, 20), std::back_inserter(result)); } Kind regards, Ola Martin

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don't give template arguments to make_iterator_range
by Matei David 07 Mar '14

07 Mar '14

Hi, I recently came across an issue with make_iterator_range(), which is used to externally construct iterator_range objects. The problem is that if a template argument is explicitly specified, gcc 4.8.2 refuses to compile the code. In the meantime, clang 3.4 compiles it without warnings. This runs contrary to the intuition that specifying a template argument can only help (speed up) compilation. You might want to make a note about this in the documentation to Boost Range: "Don't give an explicit template argument to make_iterator_range! If you do, the program will be ill-formed!" The heavily simplified problem is explained here: http://stackoverflow.com/questions/22258054/c-inconsistency-between-gcc-and… The internal Boost Range details are the following. As described here: http://www.boost.org/doc/libs/1_55_0/libs/range/doc/html/range/reference/ut… make_iterator_range has 5 overloads, all of which are template functions. Consider the 1st and 4th overloads: template <typename It> iterator_range<It> make_iterator_range(It, It); template <typename R> iterator_range<typename range_iterator<R>::type> make_iterator_range(Range&, typename range_difference<R>::type, typename range_difference<R>::type); The problem occurs if I write something like: Some_Iterator it; auto r = make_iterator_range<Some_Iterator>(it, it); Specifically, when gcc encounters this call to make_iterator_range, for a reason I don't fully understand (but others do, see the reply on SO), it does not eliminate the 2nd overload listed above from consideration, and instead it tries to instantiate the bogus type range_iterator<R> with R=Some_Iterator. I say "bogus" because the template argument of range_iterator is meant to be a range, not an iterator. In turn, this triggers a compilation error. In the meantime, clang happily eliminates the 2nd overload, probably based on the fact that it needs 3 arguments, not 2 as are given in the call. The problem disappears if I don't give an explicit template argument: auto r = make_iterator_range(it, it); even though the correct overload is indeed the first one, with argument Some_Iterator. Apparently giving an explicit template argument at that point makes the program ill-formed. I don't fully understand why, but see the SO comments. M

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