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Boost.Chrono custom I/O
by Leo Cacciari 15 Nov '17

15 Nov '17

Hi, I'm using boost.chrono in a project and I need some non-standard input-output. First of all, I need to print days as days. Consider the following code namespace testing { typedef boost::chrono::duration<long double,boost::ratio<86400>> day; } int main(int argc,char *argv[]) { using namespace testing; day d(10.5); std::cout << "Value: " << d << std::endl; } This prints Value: 10.5 [86400/1]seconds Which is obviously right; but I'd rather have: Value 10.5 days Obviously, a solution is to define operator<<(ostream&,const & day), however I'd rather use the facet approach, which looks like easier to extend to parsing and more flexible (e.g. allowing to print the above value as "10.5 days" somewhere and as "10.5 d" elsewhere.) If I understand the documentation, I must define a subclass of boost::chrono::duration_units and then imbue the facet into the stream. Is this right? Where can I found some guidelines on how to do that? Thanks for the help lc -- Leo Cacciari Aliae nationes servitutem pati possunt. Populi Romani est propria libertas.

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[Beast] Problems in getting started with Beast
by Sharklaser Lasershark 14 Nov '17

14 Nov '17

Hello! I'm migrating a project from libcurl to Beast. I'm trying to compile http_client_async.cpp <https://github.com/boostorg/beast/blob/develop/example/http/client/async/ht…>, but 110 errors come from "file_win32.ipp" and "file_win32.hpp", mostly missing declarations and members. I'm using Visual Studio 2017 (warning level 4). Here is what I have done: 1. Downloaded and set up boost 1.65.1 according to the "getting started" tutorial <http://www.boost.org/doc/libs/1_65_1/more/getting_started/windows.html> - Built all binaries - Verified header only example and binary-dependent example 2. Downloaded beast/include/boost <https://github.com/boostorg/beast/tree/develop/include/boost> from GitHub and moved the folder and .hpp to - C:\Program Files\boost\boost_1_65_1\boost 3. Started an empty project and pasted in the http_client_async.cpp <https://github.com/boostorg/beast/blob/develop/example/http/client/async/ht…> example. I have spent too many days trying to get this up and running. Any help would be greatly appreciated! Kind regards

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help on how to build mpi library
by Renfan Luo 14 Nov '17

14 Nov '17

I am a new user of boost and have downloaded 1.65.1 and unzipped it to my C:\local\boost_1_65_1. Then chose the "MPI nearest neighbour coupled phase chain." Example, file "phase_chain.cpp" as my first test in VS2015, I have got a link error message "Error LNK1104 cannot open file 'libboost_mpi-vc141-mt-1_65_1.lib" . I have checked the boost root directory and sub-directories and did not this library file. Hope guys can suggest how I build mpi library and install it to windows.

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Customized installation
by mahmood n 11 Nov '17

11 Nov '17

Hi, It is possible to build one or two targets instead of all? When I run ../b2 install --prefix=/somewhere It build all libraries. Assume I only want filesystem. Is that possible or they all depend on each other? Regards, Mahmood

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error categories point to invalid data with boost log and asio
by priv＠mariusherzog.net 11 Nov '17

11 Nov '17

I have the following problem while using boost asio together with boost log and clang 3.9.0. When I want to print an error code for example passed to me by a asio completion handler, my program crashes. This is because the error category points to invalid data. If I put a breakpoint in get_misc_error category which is called upon program startup, the local static error category already contains junk data. When I compile with gcc 5.4.0 this error does not occur. Also if I do not link against boost log everything works fine as well. I use linux, and link all boost libraries dynamically. Boost version is 1.62.0. Would it help if I maybe link boost log statically? Is there anything else I can do?

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[signals2] Connect to overloaded slots
by Florian Lindner 10 Nov '17

10 Nov '17

Hello, this code compiles just fine: #include <boost/signals2.hpp> #include <iostream> // void slot() { std::cout << "No args slot called." << std::endl; } void slot(int i) { std::cout << "Int " << i << " arg slot called." << std::endl; } int main(int argc, char **argv) { boost::signals2::signal<void(int)> s; s.connect(&slot); return 0; } However, when I uncomment the slot() function, it does not do so, anymore: boostsignals.cpp:78:5: error: no matching member function for call to 'connect' s.connect(&slot); ~~^~~~~~~ /usr/include/boost/signals2/detail/signal_template.hpp:689:18: note: candidate function not viable: no overload of 'slot' matching 'const boost::signals2::signal<void (int), boost::signals2::optional_last_value<void>, int, std::less<int>, boost::function<void (int)>, boost::function<void (const boost::signals2::connection &, int)>, boost::signals2::mutex>::slot_type' (aka 'const slot<void (int), boost::function<void (int)> >') for 1st argument connection connect(const slot_type &slot, connect_position position = at_back) ^ /usr/include/boost/signals2/detail/signal_template.hpp:693:18: note: candidate function not viable: requires at least 2 arguments, but 1 was provided connection connect(const group_type &group, ^ Is there a way to make it working with overloaded slot functions? Thanks, Florian

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(no subject)
by giridhar 08 Nov '17

08 Nov '17

Hi Boost http://bit.ly/2hcH687 giridhar

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Warning "declares a non-template function"
by mahmood n 06 Nov '17

06 Nov '17

Hi, A program needs boost > 1.58. So, I used boost-1.60 with gcc-4.8. However, as I compile the program, I get many warnings similar to /home/mahmood/boost_1_60_0/boost/mpl/set/aux_/item.hpp(47): warning: "char (&operator||(const boost::mpl::s_item<T, Base> &, boost::mpl::aux::type_wrapper<T> *))[boost::mpl::next<Base::order>::type::value]" declares a non-template function -- add <> to refer to a template instance /home/mahmood/boost_1_60_0/boost/mpl/set/aux_/item.hpp(48): warning: "boost::mpl::aux::no_tag operator%(const boost::mpl::s_item<T, Base> &, boost::mpl::aux::type_wrapper<T> *)" declares a non-template function -- add <> to refer to a template instance Lines are BOOST_MPL_AUX_SET_OVERLOAD( order_tag_, ORDER_BY_KEY, s_item, aux::type_wrapper<T>* ); BOOST_MPL_AUX_SET_OVERLOAD( aux::no_tag, IS_MASKED, s_item, aux::type_wrapper<T>* ); Does that mean I have to change that to aux::type_wrapper< >* ? Regards, Mahmood

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Under ubuntu, How to purge default boost-v1.58 then switch to the built version without any damages?
by Alex Luya 06 Nov '17

06 Nov '17

Under ubuntu 16,04 I have*built latest boost 1.65**.1 like this*: |./bootstrap.sh --prefix=/usr/local ./b2 sudo ./b2 install sudo ldconfig ***then when building something against boost,I got the**se errors:* /usr/local/include/boost/serialization/access.hpp: In instantiation of ‘static void boost::serialization::access::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive; T = std::array<std::__cxx11::basic_string<char>, 10ul>]’: /usr/local/include/boost/serialization/serialization.hpp:68:22: required from ‘void boost::serialization::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive; T = std::array<std::__cxx11::basic_string<char>, 10ul>]’ /usr/local/include/boost/serialization/serialization.hpp:126:14: required from ‘void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive; T = std::array<std::__cxx11::basic_string<char>, 10ul>]’ /usr/local/include/boost/archive/detail/oserializer.hpp:150:40: required from ‘void boost::archive::detail::oserializer<Archive, T>::save_object_data(boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::text_oarchive; T = std::array<std::__cxx11::basic_string<char>, 10ul>]’ /usr/local/include/boost/archive/detail/oserializer.hpp:103:1: required from ‘class boost::archive::detail::oserializer<boost::archive::text_oarchive, std::array<std::__cxx11::basic_string<char>, 10ul> >’ /usr/local/include/boost/archive/detail/oserializer.hpp:255:13: required from ‘static void boost::archive::detail::save_non_pointer_type<Archive>::save_standard::invoke(Archive&, const T&) [with T = std::array<std::__cxx11::basic_string<char>, 10ul>; Archive = boost::archive::text_oarchive]’ /usr/local/include/boost/archive/detail/oserializer.hpp:310:22: required from ‘static void boost::archive::detail::save_non_pointer_type<Archive>::invoke(Archive&, const T&) [with T = std::array<std::__cxx11::basic_string<char>, 10ul>; Archive = boost::archive::text_oarchive]’ /usr/local/include/boost/archive/detail/oserializer.hpp:534:18: required from ‘void boost::archive::save(Archive&, T&) [with Archive = boost::archive::text_oarchive; T = const std::array<std::__cxx11::basic_string<char>, 10ul>]’ /usr/local/include/boost/archive/detail/common_oarchive.hpp:70:22: required from ‘void boost::archive::detail::common_oarchive<Archive>::save_override(T&) [with T = const std::array<std::__cxx11::basic_string<char>, 10ul>; Archive = boost::archive::text_oarchive]’ /usr/local/include/boost/archive/basic_text_oarchive.hpp:83:9: required from ‘void boost::archive::basic_text_oarchive<Archive>::save_override(T&) [with T = const std::array<std::__cxx11::basic_string<char>, 10ul>; Archive = boost::archive::text_oarchive]’ /usr/local/include/boost/archive/detail/interface_oarchive.hpp:70:9: required from ‘Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(const T&) [with T = std::array<std::__cxx11::basic_string<char>, 10ul>; Archive = boost::archive::text_oarchive]’ examples/user_code/openpose_recognition.cpp:867:89: required from here /usr/local/include/boost/serialization/access.hpp:116:9: error: ‘struct std::array<std::__cxx11::basic_string<char>, 10ul>’ has no member named ‘serialize’ t.serialize(ar, file_version); ^ compilation terminated due to -Wfatal-errors. Makefile:478: die Regel für Ziel „.build_release/examples/user_code/openpose_recognition.o“ scheiterte make: *** [.build_release/examples/user_code/openpose_recognition.o] Fehler 1 make: *** Auf noch nicht beendete Prozesse wird gewartet … | |*I think ubuntu is still use default boost that installed by apt-get,so I tried to pur**ge it * sudo apt-get purge libboost1.58-dev| *the output asks me to remove a lot of stuffs **that depend on libboost1.58-dev **like these:* Die folgenden Pakete wurden automatisch installiert und werden nicht mehr benötigt: docutils-common fltk1.3-doc fluid gazebo7 gazebo7-common gazebo7-plugin-base gir1.2-gtk-2.0 libapr1 libapr1-dev libaprutil1 libaprutil1-dev libarmadillo6 libassimp-dev libassimp3v5 libboost-atomic1.58.0 libboost-chrono1.58.0 libboost-context1.58.0 libboost-coroutine1.58.0 libboost-graph-parallel1.58.0 libboost-graph1.58.0 libboost-locale1.58.0 libboost-log1.58.0 libboost-math1.58.0 libboost-mpi-python1.58.0 libboost-mpi1.58.0 libboost-python1.58.0 libboost-random1.58.0 libboost-regex1.58.0 libboost-signals1.58.0 libboost-test1.58.0 libboost-thread1.58.0 libboost-timer1.58.0 libboost-tools-dev libboost-wave1.58.0 libboost1.58-tools-dev libbullet-dev libbulletcollision2.83.6 libbulletdynamics2.83.6 libbulletsoftbody2.83.6 libbz2-dev libcollada-dom2.4-dp-dev libcollada-dom2.4-dp0 libconsole-bridge-dev libconsole-bridge0.2v5 libcurl4-openssl-dev libdap-dev libdap17v5 libdapclient6v5 libdapserver7v5 libepsilon1 libflann-dev libflann1.8 libfltk-cairo1.3 libfltk-forms1.3 libfltk-images1.3 libfltk1.3-dev libfreeimage-dev libfreeimage3 libfreexl1 libgazebo7 libgdal-dev libgdal1i libgeos-3.5.0 libgeos-c1v5 libgeos-dev libgl2ps-dev libgtest-dev libgtk2.0-dev libgts-0.7-5 libgts-bin libgts-dev libhdf4-0-alt libhdf4-alt-dev libhdf5-mpi-dev libignition-math2 libignition-math2-dev libinput-dev libjs-jquery-ui libjsoncpp-dev libjxr0 libkmlbase1 libkmldom1 libkmlengine1 libldap2-dev liblinearmath2.83.6 liblog4cxx-dev liblog4cxx10-dev liblog4cxx10v5 liblz4-dev libminizip1 libnetcdf-c++4 libnetcdf-cxx-legacy-dev libnetcdf-dev libnetcdf11 libogdi3.2 libogre-1.9.0v5 libopenni-dev libopenni-sensor-pointclouds0 libopenni0 ....... ,and it may cause a lot of damage if continuing,so the question is |*How to purge default boost-v1.58 then switch to the built version without any damages?*|

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[asio] Does ssl::stream allow multiple pending async operations?
by Phil Sean 06 Nov '17

06 Nov '17

The documentation for ssl::stream says: "Shared objects: Unsafe. The application must also ensure that all asynchronous operations are performed within the same implicit or explicit strand." Does this mean we have to wait for an async operation to finish before another is started (for read/read, read/write, and write/write)? (Async operations refer to async_read_some() and async_write_some(), not the composed operations.) If so, is the operation said to have finished when the handler is invoked or when the handler returns? That is: void handler( const boost::system::error_code& error, std::size_t bytes_transferred ) { // Does the operation finish here ... } // or here? If not, what's the difference between the async operations of ip::tcp::socket and ssl::stream then (as strand just avoids concurrency for the thread-unsafe)? I came across different views on this problem. This answer[1] suggests that simply using the same strand (ie. no concurrency) will suffice. Another one[2] says multiple pending asynchronous operations can be problematic for ssl::stream even if no concurrency occurs. Thanks. [1] https://stackoverflow.com/questions/27212123/executing-asynchronous-operati… [2] https://stackoverflow.com/questions/15352472/using-boosts-ssl-asio-code-asy…

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