- Boost-users - lists.boost.org

boost::any constructors
by David 22 Feb '16

22 Feb '16

Hi, boost::any has a perfect forward constructor declared as: template<typename ValueType> any(ValueType&& value , typename boost::disable_if<boost::is_same<any&, ValueType> >::type* = 0 // disable if value has type `any&` , typename boost::disable_if<boost::is_const<ValueType> >::type* = 0) // disable if value has type `const ValueType&&` : content(new holder< typename decay<ValueType>::type >(static_cast<ValueType&&>(value))) {} The is_const SFINAE exclusion forces const types to the regular copy constructor: template<typename ValueType> any(const ValueType & value) : content(new holder< BOOST_DEDUCED_TYPENAME remove_cv<BOOST_DEDUCED_TYPENAME decay<const ValueType>::type>::type >(value)) {} What is different about how the regular copy constructor treats a constant value than what the perfect forward construct would do if the is_const exclusion were removed? Thanks, David

2 1

Nested BOOST_FOREACH crash
by peyman＠ausdia.com 22 Feb '16

22 Feb '16

Good Day Boosters! I am experiencing sporadic crashes that look like memory problem when I have nested (2 level) BOOST_FOREACH loops. Reason I say it looks like memory problem is because slightest change will make it crash or not crash. For example, adding a simple cout would change it! I cannot provide a testcase. So I am just wondering if anybody has experienced the same, or know what could be going on. I am using Boost 1.57. Cheers, Peyman

2 1

Need help when adapting boost 1.59.0 to WinRT
by Nguyễn Trung Duy 22 Feb '16

22 Feb '16

Dear Boost team, I need your help with adapting boost 1.59 to WinRT. I am working on boost and reSIProcate. I built boost and integrated it with reSIProcate project. However, when build reflow project, I got stuck with bellow bugs. I wonder with your great experiences, could you please give me some advice. The error happens at line 96 : #if defined(BOOST_ASIO_WINDOWS_RUNTIME) const int max_addr_v4_str_len = 256; const int max_addr_v6_str_len = 256; typedef unsigned __int32 u_long_type; typedef unsigned __int16 u_short_type; struct in4_addr_type { u_long_type s_addr; }; // error at here And the logs: *\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(96): error C3927: '->': trailing return type is not allowed after a non-function declarator (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(96): error C3484: syntax error: expected '->' before the return type (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(96): error C3613: missing return type after '->' ('int' assumed) (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(96): error C3646: 'S_addr': unknown override specifier (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(98): error C3927: '->': trailing return type is not allowed after a non-function declarator (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(98): error C3484: syntax error: expected '->' before the return type (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(98): error C3613: missing return type after '->' ('int' assumed) (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(98): error C3646: 'Byte': unknown override specifier (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(98): error C2143: syntax error: missing ',' before '[' (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(98): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(98): error C2143: syntax error: missing ')' before ';' (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(98): error C2143: syntax error: missing ';' before ')' (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/detail/socket_types.hpp(98): error C2059: syntax error: ')' (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/ip/address_v4.hpp(61): error C2039: 'S_addr': is not a member of 'default::uint32' (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/ip/address_v4.hpp(147): error C2039: 'S_addr': is not a member of 'default::uint32' (compiling source file MediaStream.cxx)\boost-msvc-14.0-store\boost/asio/ip/address_v4.hpp(153): error C2039: 'S_addr': is not a member of 'default::uint32' (compiling source file MediaStream.cxx)* Thanks you so much!!!! *--* *Best Regards,* *NGUYEN TRUNG DUY* *Android Developer* *Mobile*: (+84)977 46 12 23 *Skype :* trungduy150388 *Website*: http://nguyentrungduy.com/ *Blog*: http://dbox.nguyentrungduy.com/ *Github*: https://github.com/nguyentrungduy

2 2

Newbie
by Shan Wijesinghe 22 Feb '16

22 Feb '16

Hi all, I'm a new member to C++ boost and I have a fairly good knowledge in programming in C++. I'm very much excited to join this group and I need directions from the senior members on how to start myself. Please help me here. Thanks in advance. regards, DilSHAN.

6 11

Query on Boost.DLL
by Leo Carreon 21 Feb '16

21 Feb '16

Hi, I have been reading the Boost.DLL documentation. Can a single plugin support multiple API’s? If yes, when the multiple API’s are used at the same time; will there be only one instance of the plugin loaded or will there be multiple instances loaded? Regards, Leo

2 1

Boost.DLL
by Leo Carreon 21 Feb '16

21 Feb '16

Hi, Can anyone please let me know what the status of the Boost.DLL library is? Regards, Leo

2 1

[coroutine] - only std exceptions are caught from coroutines
by Tamas.Ruszkai＠leica-geosystems.com 21 Feb '16

21 Feb '16

3 4

[Interprocess] Communication between x86 and x64 issue
by Toni Neubert 19 Feb '16

19 Feb '16

I want to communicate between different platforms using boost interprocess. I am using vc12 and boost 1.58 on windows 7. My code below is a very simple example, that should work. But it doesn't for communications between different platforms... If I create it in x64 and open in win32, the process stuck at a lock at function try_based_lock in boost/int/sync/detail/common_algorithms.hpp In the other way around: win32 create, x64 open: the process crashes at name_length in segment_manager_helper.hpp while trying to find the name in index (priv_generic_find in segment_manager). #include <iostream> #include <boost/interprocess/managed_shared_memory.hpp> int main() { namespace bip = boost::interprocess; // open in WIN32, create in x64 #ifdef _WIN32 bip::managed_shared_memory msm(bip::open_only, "TestIPC"); #elsif X64 bip::shared_memory_object::remove("TestIPC"); bip::managed_shared_memory msm(bip::create_only, "TestIPC", 4096); msm.construct<uint32_t>("Data")[1](10); #endif // Get Data and print it auto data = msm.find<uint32_t>("Data"); if (data.second == 1) { std::cout << *data.first << std::endl; } std::cin.ignore(); return 0; } Does anybody have experience in this? Thank you in advance!

3 2

Re: [Boost-users] [Serialization] This compiles; but does it work?
by Bjorn Reese 19 Feb '16

19 Feb '16

On 02/19/2016 04:20 AM, Merrill Cornish wrote: > Can anyone tell me if this will work, or do I need to implement the > serialize() function? When you are doing different things for the input and output archives then it is better to split serialization into load and save: #include <boost/filesystem/path.hpp> #include <boost/serialization/split_free.hpp> namespace boost { namespace serialization { template <typename Archive> void serialize(Archive& ar, filesystem::path& p, const unsigned int version) { split_free(ar, p, version); } template<class Archive> void save(Archive & ar, const filesystem::path& p, unsigned int version) { ar << p.string(); } template<class Archive> void load(Archive & ar, filesystem::path& p, unsigned int version) { std::string data; ar >> data; p = data; } }}

2 1

[graph] Search algorithm using quality metric rather than distance
by rleigh＠codelibre.net 19 Feb '16

19 Feb '16

I have an adjacency_list graph (shown in attached dot file). Each edge has an attached "quality metric" as a bundled property. Similar to the dijkstra_shortest_paths algorithm, I'd like to determine the optimal path. However, this algorithm sums the distance along each edge, and finds the shortest path. What I'd like to do is *multiply* the quality metric for each edge in the path, and find the largest one. A perfect path will have a quality metric of 1.0, while suboptimal paths will have values tending towards zero, and the more "bad" edges the smaller the number. I'll likely then look at the number of edges and then select the shortest of the candidates. It seems like a simple algorithm that might already be included, but I just haven't found it yet not knowing its formal name. If anyone has any suggestions, I'd be very grateful. Many thanks, Roger

5 4