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[optional] warning removal
by Vicente J. Botet Escriba 21 Oct '12

21 Oct '12

Hi, can I commit this simple patch Best, Vicente svn diff ../../../boost/optional/ Index: ../../../boost/optional/optional.hpp =================================================================== --- ../../../boost/optional/optional.hpp (revision 81020) +++ ../../../boost/optional/optional.hpp (working copy) @@ -890,12 +890,12 @@ template<class T> inline -bool operator == ( none_t x, optional<T> const& y ) +bool operator == ( none_t , optional<T> const& y ) { return equal_pointees(optional<T>() ,y); } template<class T> inline -bool operator < ( none_t x, optional<T> const& y ) +bool operator < ( none_t , optional<T> const& y ) { return less_pointees(optional<T>() ,y); } template<class T>

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[thread] Integration with Chrono and DateTime (was: [release][1.52] Release Notes)
by Andrey Semashev 20 Oct '12

20 Oct '12

On Oct 13, 2012 12:10 AM, "Vicente J. Botet Escriba" < vicente.botet(a)wanadoo.fr> wrote: > > Le 12/10/12 21:51, Andrey Semashev a écrit : > >> On Oct 12, 2012 8:35 PM, "Vicente J. Botet Escriba" < >> vicente.botet(a)wanadoo.fr> wrote: >>> >>> Hi, >>> Why you don't want to depend on Boost.Chrono? >> >> Because I want to minimize dependencies (especially, binary build >> dependencies). > > Me too, I want to limit dependencies :) Fair enough. Perhaps, we could absract away Boost.Thread from both libraries? Seems like a logical solution for a case like this. For example, Boost.Thread could define an internal interface for integrating with time units from different libraries. Chrono and DateTime would support this interface, and Boost.Thread could also provide the necessary glue for std::chrono integration. I think, Boost.Thread could use its own time units internally and use ADL-found functions to convert from other time units. Boost.Thread will not depend on either timing library then. Does this look viable? >> Unlike Boost.DateTime, Boost.Chrono is not needed by my library, so this >> would really be a false dependency. > > If you don't need time related thread facilities you could set BOOST_THREAD_DONT_USE_CHRONO. Would this work for you? Yes, that's what I'm doing now. I'm using DateTime units for timed functions. >> I understand that the dual interface adds more redundancy but does it >> really require active maintenance? The code has been there for quite some >> time, it's well tested and doesn't require additional work. >> >> > Any addition code has its influence on how the library could evolve. I really would prefer to remove these interfaces for Boost 1.56. I think that 1 year and a half is enough time to move to the new interface. Then I think library decoupling is the right way even more.

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Boost.log: set_channel name dynamically for a basic_composite_logger
by syvyi 20 Oct '12

20 Oct '12

Hi, how to set attribute dynamically for a composite logger? lass my_logger_mt : public src::basic_composite_logger< char, my_logger_mt, src::multi_thread_model<boost::log_mt_nt5::aux::light_rw_mutex>, src::features< src::severity< severity_levels >, src::exception_handler, src::channel< std::string > > > { BOOST_LOG_FORWARD_LOGGER_CONSTRUCTORS(my_logger_mt) }; -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-log-set-channel-name-dynamically-f… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[thread] deprecating Mutex::scoped_lock and Mutex::scoped_try_lock and boost::condition
by Vicente J. Botet Escriba 20 Oct '12

20 Oct '12

Hi, I would like to deprecate the following features in Boost.Thread: * Mutex::scoped_lock and Mutex::scoped_try_lock so that we can make mutex types independent from locks. The user should use instead unique_lock<Mutex> and the new public class try_unique_lock. * condition: This was there for forward compatibility since 1.35. The user should use instead condition_variable_any. What do you think? Best, Vicente

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boost::python feature request: unique_ptr, interfaces and factory functions
by Maxim Yegorushkin 20 Oct '12

20 Oct '12

Hi Boost, I am using boost::python to expose a C++ API into Python. The class I would like to export is: struct Subscriber { virtual ~Subscriber() = 0; static std::unique_ptr<Subscriber> create(); }; It's an interface with a factory function returning a std::unique_ptr<>. I would like to be able to export it in the following manner: BOOST_PYTHON_MODULE(pub_sub) { boost::python::class_< Subscriber , std::unique_ptr<Subscriber> , boost::noncopyable >("Subscriber") .def(boost::python::init<>, Subscriber::create) ; ; } I.e., the python wrapper would hold a std::unique_ptr<Subscriber> and use Subscriber::create() factory function as a constructor for Python Subscriber class. The above code doesn't compile with boost-1.51.0 for two reasons: * std::unique_ptr<> is not supported by boost::python. On the other hand, std::auto_ptr<> is. * The factory function can't be used used as a Python object constructor. I thought there could be a way to specialize certain boost::python traits/metaclasses to make it work with std::unique_ptr<> and factory functions as constructors, but couldn't figure it out. The workaround I managed to get working is: std::auto_ptr<Subscriber> createSubscriber() { return std::auto_ptr<Subscriber>(Subscriber::create().release()); } BOOST_PYTHON_MODULE(pub_sub) { // Expose the class. boost::python::class_< Subscriber , std::auto_ptr<Subscriber> , boost::noncopyable >("Subscriber_", boost::python::no_init) ; ; // Expose its factory function. boost::python::def("Subscriber", createSubscriber); } I.e., std::unique_ptr<> gets replaced with std::auto_ptr<>, the Python class is renamed to Subscriber_ and the factory function gets exported as Subscriber allowing for Python syntax: import pub_sub s = pub_sub.Subscriber() # however assert isinstance(s, pub_sub.Subscriber) # fails assert isinstance(s, pub_sub.Subscriber_) # succeeds So, I was wondering if there are ways to make my original Python class export syntax work? -- Maxim

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[test] new features use c++11 features
by Jürgen Hunold 19 Oct '12

19 Oct '12

Hi Gennadiy, the new features introduced in revision 81010 and81011 use c++ features unconditionally. This breaks compilation of Boost.Test on all older compilers. Even the recent gcc-4.6 (Ubuntu 12.04). The critical places are: std::tuple std::shared_ptr std::false_type std::remove_cv those can be replaced with std::tr1:: equivalents using boost/tr1. See a quick patch attached. The usage of std::enable_if is critical, as I could not find it in boost::tr1. But this should be available as boost::enable_if and be detected by the appropriate Boost.Config macro. And at least gcc-4.6.3 ist missing the angle bracket hack, so closing ">>" template argument lists are interpreted as operator >>. Also patched. Could you please try your changes with an older compiler first? As I can not use c++11 at the moment (I'm stuck with gcc-4.2) I would like to use the new features with this older compiler. Yours, Jürgen -- * Dipl.-Math. Jürgen Hunold ! * voice: ++49 4257 300 ! Fährstraße 1 * fax : ++49 4257 300 ! 31609 Balge/Sebbenhausen * jhunold(a)gmx.eu ! Germany

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[iterator] Using zip_iterator with std::pair
by "Claas H. Köhler" 19 Oct '12

19 Oct '12

Hi! I would like to use the boost::zip_iterator with std::pair. Unfortunately this does not work out of the box, but there exists a namespace boost::detail::tuple_impl_specific, which apparently needs to be specialised for each tuple type. I managed to re-implement tuple_meta_transform and tuple_meta_accumulate for std::tuple, which seems to be straightforward. However, there are functions of the form template<typename Tuple, typename Fun> complex_result_type tuple_transform(const Tuple&, Fun) which have to be overloaded as well, if I am not mistaken. However, overloading this with something like template<typename... Args, typename Fun> complex_result_type tuple_transform(const std::tuple<Args...>&, Fun) is probably not going to work, since this would be a partial template specialisation of a function. What is the recommended way of proceeding here? Or am I making things to complicated and there exists a simpler solution to using the zip iterator with std::pair / std::tuple. Any support would be appreciated. Regards Claas P.S: I am using boost 1.50 with gcc-4.6 and the C++11 standard.

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[graph] dijkstra_shortest_paths solution stability
by Jan Hudec 18 Oct '12

18 Oct '12

Hello All, I need to implement an algorithm, that uses dijkstra's algorithm as key component. However it has two additional requirements on it: 1. If for any two vertices u, v there is an edge and a path of the same length through additional vertices, the direct edge is always selected and 2. If for any two vertices u, v there is more than one shortest path, all calculates shortest path trees that include path u, v contain the same path between those vertices. Now the article that describes the algorithm uses additional property with random values to disambiguate the paths, but I am sure the following two simple rules will achieve the effect more easily: 1. When u is reached at the same distance through two vertices, v and w, the one with lower distance from start will be used in the shortest path tree. 2. When u is reached at the same distance through two vertices, v and w, that both have the same distance from start, the one that comes first in some arbitrary fixed total ordering will be used inthe shortest path tree. These rules are trivially implementable by: 1. Not updating the parent map if the new distance is not strictly less. 2. Using additional criterion in the heap comparing the vertices by index or descriptor if they have the same tentative distance. Now I suspect rule 1 is already satisfied though it's not documented. And if rule 2 is not satisfied, would it be more generally useful and worth, possibly optionally, implementing in the library? -- Jan 'Bulb' Hudec <bulb(a)ucw.cz>

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Fix some "unused variable" warnings
by Martin Martin 18 Oct '12

18 Oct '12

Hi, I'm using boost with clang++, with some style-related warnings turned on, and got a few warnings for unused variables. Here's the patch; are you interested in these changes? If so, is there a better way to get them to you? Thanks, Martin --- boost_1_51_0/boost/date_time/dst_rules.hpp 2008-02-27 15:00:24.000000000 -0500 +++ boost_1_51_0-fixed/boost/date_time/dst_rules.hpp 2012-10-18 09:31:08.433591299 -0400 @@ -369,11 +369,11 @@ const time_duration_type&) { return is_not_in_dst; } - static bool is_dst_boundary_day(date_type d) + static bool is_dst_boundary_day(date_type) { return false; } static time_duration_type dst_offset() diff '--unified=5' -r boost_1_51_0/boost/optional/optional.hpp boost_1_51_0-fixed/boost/optional/optional.hpp --- boost_1_51_0/boost/optional/optional.hpp 2010-12-18 16:29:39.000000000 -0500 +++ boost_1_51_0-fixed/boost/optional/optional.hpp 2012-10-18 09:31:50.737591130 -0400 @@ -888,16 +888,16 @@ // none vs optional<T> cases // template<class T> inline -bool operator == ( none_t x, optional<T> const& y ) +bool operator == ( none_t, optional<T> const& y ) { return equal_pointees(optional<T>() ,y); } template<class T> inline -bool operator < ( none_t x, optional<T> const& y ) +bool operator < ( none_t, optional<T> const& y ) { return less_pointees(optional<T>() ,y); } template<class T> inline bool operator != ( none_t x, optional<T> const& y )

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[container] #7531 shadowing warnings under gcc
by Jeffrey Lee Hellrung, Jr. 18 Oct '12

18 Oct '12

Ion: I just wanted to make sure you see this. I can identify and make the necessary changes to trunk then release if you want me to. https://svn.boost.org/trac/boost/ticket/7531 Thanks, - Jeff

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