February 2012 - Boost-users - lists.preview.boost.org

[asio] mingw compile problem
by Tim Blechmann 18 Feb '12

18 Feb '12

hi all, i'm using asio successfully on both linux and osx. but when compiling via mingw, i get the two compile errors, both are related to const-correctness. problem 1: In file included from /home/tim/workspace/supercollider/external_libraries/boost/boost/asio/detail/win_iocp_serial_port_service.hpp:225, from /home/tim/workspace/supercollider/external_libraries/boost/boost/asio/serial_port_service.hpp:26, from /home/tim/workspace/supercollider/external_libraries/boost/boost/asio/basic_serial_port.hpp:30, from /home/tim/workspace/supercollider/external_libraries/boost/boost/asio.hpp:25, from /home/tim/workspace/supercollider/server/supernova/sc/../server/../sc/../utilities/osc_server.hpp:25, from /home/tim/workspace/supercollider/server/supernova/sc/../server/../sc/sc_osc_handler.hpp:35, from /home/tim/workspace/supercollider/server/supernova/sc/../server/server.hpp:27, from /home/tim/workspace/supercollider/server/supernova/sc/sc_plugin_interface.cpp:31: /home/tim/workspace/supercollider/external_libraries/boost/boost/asio/detail/impl/win_iocp_serial_port_service.ipp: In member function ‘boost::system::error_code boost::asio::detail::win_iocp_serial_port_service::open(boost::asio::detail::win_iocp_handle_service::implementation_type&, const std::string&, boost::system::error_code&)’: /home/tim/workspace/supercollider/external_libraries/boost/boost/asio/detail/impl/win_iocp_serial_port_service.ipp:58: error: invalid conversion from ‘const char*’ to ‘CHAR*’ /home/tim/workspace/supercollider/external_libraries/boost/boost/asio/detail/impl/win_iocp_serial_port_service.ipp:58: error: initializing argument 1 of ‘void* CreateFileA(CHAR*, DWORD, DWORD, _SECURITY_ATTRIBUTES*, DWORD, DWORD, void*)’ problem 2: /home/tim/workspace/supercollider/external_libraries/boost/boost/asio/buffer.hpp: In function ‘PointerToPodType boost::asio::buffer_cast(const boost::asio::const_buffer&) [with PointerToPodType = void*]’: /home/tim/workspace/supercollider/external_libraries/boost/boost/asio/detail/impl/win_iocp_handle_service.ipp:322: instantiated from here /home/tim/workspace/supercollider/external_libraries/boost/boost/asio/buffer.hpp:428: error: invalid static_cast from type ‘const void*’ to type ‘void*’ any idea, how i can work around these issues? thanks, tim

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[Boost Statechart Library] How to inherit reactions?
by Philipp Bender 18 Feb '12

18 Feb '12

Hi, I'd like to define an abstract state which reacts to a specific event and calls a virtual hook function. In classes which inherit from my base class, I'd like to define those hooks. struct EvHeartBeat : boost::statechart::event<EvHeartBeat> {}; struct EvMyFoo : boost::statechart::event<EvMyFoo> {}; // this is my base class template< class MostDerived, class Context, class InnerInitial = boost::mpl::list<>, boost::statechart::history_mode historyMode = boost::statechart::has_no_history > struct BaseState : public boost::statechart::simple_state< MostDerived, Context, InnerInitial, historyMode > { typedef BaseState< MostDerived, Context, InnerInitial, historyMode > base_state; typedef boost::mpl::list< boost::statechart::custom_reaction< EvHeartBeat > > reactions; const std::string name; virtual boost::statechart::result hook() = 0; boost::statechart::result react ( const EvHeartBeat& e) { return hook(); } }; // this is my derived class struct B : BaseState<B, SomeContext, InitialState > { typedef boost::mpl::list< boost::statechart::custom_reaction<EvMyBar> > my_reactions; typedef boost::mpl::insert_range<my_reactions, boost::mpl::end<my_reactions>::type, BBFState::bbf_state::reactions>::type reactions; boost::statechart::result react ( const EvMyFoo& ) { std::cout << "B's reaction" << std::endl; } }; The derived class needs some explanation: I want it to react to other events as well, therefore the my_reactions typedef. Then I merge the mpl::list reactions from base and derived, this is a bit ugly but should be a generic way to do get the desired result. Now the problem: My compiler (g++-4.4) complains that there is no B::react( const EvHeartBeat& ) method. But it should, it's in the parent class. Furthermore, if I _remove_ the reaction to the other event, it compiles and actually uses the parent's reaction method. Of course I can find a workaround (including some boiler plate code), but as this will be an integral part of my project, I'd like it to be as correct, maintainable and elegant as possible. I'd be happy to get some opinions about what's wrong here, best regards Philipp

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Compiling Boost libraries without libstlport.so on Sun
by Shinil Gangadharan 18 Feb '12

18 Feb '12

Hi, Since libstlport.so is not compatable with libiostream.so, I am trying to get rid of libstlport.so on Sun C++ compiler V5.9. I am currently using boost version 1_46_1. Since boost libraries are dependent on libstlport.so, is there a workaround so that the libraries compile with libiostream.so instead of libstlport.so. Regards, Shinil V.G.

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Is it possible to expose bit-fields through boost.python
by Andy Falanga (afalanga) 17 Feb '12

17 Feb '12

Hi, I'd like to be able expose a struct defined as a bit field in C++ to python. Being a neophyte in Boost, I'm wondering if there's a way to doing this. I'm trying the method that I used when exposing a conventional struct, but the intellisense in Visual Studio is complaining to me that bit-fields can't be exposed. I'm sure most on this list know what I mean, but just in case: struct bitField { char bit1 : 1; char bit2 : 1; char bit34 : 2; char bit567 : 3; char bit8 : 1; }; class_<bitField>("BitField") .def_readwrite("bit1", &bitField::bit1) .def_readwrite("bit2", &bitField::bit2) .def_readwrite("bit34", &bitField::bit34) .def_readwrite("bit567", &bitField::bit567) .def_readwrite("bit8", &bitField::bit8) ; Is there a way of doing this? This pattern is what I used to expose a conventional struct. Thanks, Andy

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Re: [Boost-users] Boost Python and Crypto++
by Boost Users List 17 Feb '12

17 Feb '12

> when I try to import it into Python, I receive this error: > > ImportError: nf_decrypt.so: undefined symbol: > _ZN8CryptoPP21SimpleKeyingInterface6SetKeyEPKhmRKNS_14NameValuePairsE >[...] This does not sound like a Python problem. Are you linking with the appropriate -lfoo switches? -- VZ Thanks VZ! I wasn't linking in Crypto++ correctly. I got it working. Now have to figure out how to convert Python buffer objects to C++ std::strings.

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[asio::serial_port] I can read and write synchronously, but how do I unblock when I want to end?
by Dario Ramos 17 Feb '12

17 Feb '12

I'm using boost::asio::serial_port to read and write to a serial port device. I do the reading inside a boost::thread to take advantage of RS-232 being full-duplex. My read calls are like this one: BYTE b; read( m_SerialPort, boost::asio::buffer(&b,1) ); Everything works OK except for shutdown. When I want to end the thread, it's almost always blocked in a read call. How do I unblock it? I tried: - Calling close on the port: This generates an exception, which I can catch, but I was told I can't distinguish shutdown from error if I do this. - Stopping the io_service I passed to the serial_port's constructor. This had no effect, the thread remained blocked on the read call. -- *Darío Eduardo Ramos* Meditech S.A. www.meditech.com.ar (+54) 01147603300, Interno 31 Av. Julio A. Roca 3456 Florida Oeste, Bs.As. Argentina

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Re: [Boost-users] undefined reference to '__sync_add_and_fetch_4'when cross-compiling boost::asio fors mips
by Jayne 17 Feb '12

17 Feb '12

Hello Andreas, Thank you for the reply. I have made some progress since my initial post, I have found that part of the problem is that I am using gcc 4.2 and the various #defines for atomics assume that 4.2 will have the appropriate support. The compiler expects that `__sync_add_and_fetch_4' will be provided. I've found there is some assembler provided with the compiler which gives a 'atomic_exchange_and_add' macro which I've had working correctly in a demo programme, but I haven't yet got it integrated with boost, though that would be a nice long-term solution. Back to the problem though. I've tried a clean build with BOOST_ASIO_DISABLE_FENCED_BLOCK but I'm still getting the same problem. I've attached the build output below. Here are the steps I took to make the clean build: 1. unzip boost_1_48_0.zip 2. mkdir boost-binary 3. set and export BOOST_BUILD_ROOT=/home/jayne/boost-stb/boost_1_48_0 export BOOST_BUILD_ROOT BOOST_BIN_ROOT=$BOOST_BUILD_ROOT/boost-binary export BOOST_BIN_ROOT 4. ./bootstrap.sh 5. Edit the resulting project-config.jam file (which has been generated for the host x86 system) using gcc : mipsel : mipsel-linux-g++ ; and option.set prefix : /opt/brcm/stblinux-2.6.31 ; option.set exec-prefix : /opt/brcm/stblinux-2.6.31 ; option.set libdir : /opt/brcm/stblinux-2.6.31/lib ; option.set includedir : /opt/brcm/stblinux-2.6.31/include/linux ; 6. Edit tools/build/v2/tools/gcc.jam to remove ‘-pendantic’ option (otherwise the string library assembler will not compile) 7. Run ./b2 cxxflags=-DBOOST_ASIO_DISABLE_FENCED_BLOCK --without-python --without-mpi 8. Run ./b2 threading=multi variant=release link=shared toolset=gcc --build-dir=$BOOST_BIN_ROOT --prefix=/tmp/boost --without-python --without-mpi install While compiling in step 7, a typical compiler line is: "mipsel-linux-g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -pthread -fPIC -DBOOST_ASIO_DISABLE_FENCED_BLOCK -Wextra -Wno-long-long -pedantic -DBOOST_ALL_DYN_LINK=1 -DBOOST_ALL_NO_LIB=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_DEPRECATED -DNDEBUG -I"." -c -o "bin.v2/libs/chrono/build/gcc-mipsel/release/threading-multi/process_cpu_clocks.o" "libs/chrono/src/process_cpu_clocks.cpp" This is the output from build: /opt/bcmtools/bin/mipsel-linux-g++ -O2 -I/tmp/boost/include echo_server.o network_utilities.o sha1.o base64.o md5.o uri.o hybi_header.o data.o atomic.o -o echo_server -L/tmp/boost/lib -lboost_regex -lboost_date_time -lboost_program_options -lboost_system -lboost_thread echo_server.o: In function `boost::asio::detail::wait_handler::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned int)': echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail12wait_handlerINS_3_bi6bind_tIvNS_4_mfi3mf0IvN11websocketpp4role6serverINS7_8endpointIS9_NS7_6socket5plainENS7_3log6loggerEEEEEEENS3_5list1INS3_5valueIPSG_EEEEEEE11do_completeEPNS1_15task_io_serviceEPNS1_25task_io_service_operationERKNS_6system10error_codeEj+0x94): undefined reference to `__sync_lock_test_and_set_4' echo_server.o: In function `boost::asio::detail::wait_handler::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned int)': echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail12wait_handlerINS_3_bi6bind_tIvNS_4_mfi3mf1IvN11websocketpp10connectionINS7_8endpointINS7_4role6serverENS7_6socket5plainENS7_3log6loggerEEENSB_ISG_E10connectionENSD_ISG_E10connectionEEERKNS_6system10error_codeEEENS3_5list2INS3_5valueINS_10shared_ptrISL_EEEEPFNS_3argILi1EEEvEEEEEE11do_completeEPNS1_15task_io_serviceEPNS1_25task_io_service_operationESP_j+0xd4): undefined reference to `__sync_lock_test_and_set_4' echo_server.o: In function `boost::asio::detail::reactive_socket_accept_op::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned int)': echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail25reactive_socket_accept_opINS0_12basic_socketINS0_2ip3tcpENS0_21stream_socket_serviceIS5_EEEES5_NS_3_bi6bind_tIvNS_4_mfi3mf2IvN11websocketpp4role6serverINSD_8endpointISF_NSD_6socket5plainENSD_3log6loggerEEEEENS_10shared_ptrINSD_10connectionISL_NSM_10connectionENSI_ISL_E10connectionEEEEERKNS_6system10error_codeEEENS9_5list3INS9_5valueIPSM_EENS10_IST_EEPFNS_3argILi1EEEvEEEEEE11do_completeEPNS1_15task_io_serviceEPNS1_25task_io_service_operationESX_j+0xdc): undefined reference to `__sync_lock_test_and_set_4' echo_server.o: In function `boost::asio::detail::reactive_socket_service_base::start_op(boost::asio::detail::reactive_socket_service_base::base_implementation_type&, int, boost::asio::detail::reactor_op*, bool, bool)': echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail28reactive_socket_service_base8start_opERNS2_24base_implementation_typeEiPNS1_10reactor_opEbb+0x1b0): undefined reference to `__sync_fetch_and_add_4' echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail28reactive_socket_service_base8start_opERNS2_24base_implementation_typeEiPNS1_10reactor_opEbb+0x2b4): undefined reference to `__sync_fetch_and_add_4' echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail28reactive_socket_service_base8start_opERNS2_24base_implementation_typeEiPNS1_10reactor_opEbb+0x2ec): undefined reference to `__sync_fetch_and_add_4' echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail28reactive_socket_service_base8start_opERNS2_24base_implementation_typeEiPNS1_10reactor_opEbb+0x3cc): undefined reference to `__sync_fetch_and_add_4' echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail28reactive_socket_service_base8start_opERNS2_24base_implementation_typeEiPNS1_10reactor_opEbb+0x548): undefined reference to `__sync_fetch_and_add_4' echo_server.o:echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail28reactive_socket_service_base8start_opERNS2_24base_implementation_typeEiPNS1_10reactor_opEbb+0x65c): more undefined references to `__sync_fetch_and_add_4' follow echo_server.o: In function `boost::asio::detail::reactive_socket_send_op::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned int)': echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail23reactive_socket_send_opINS1_17consuming_buffersINS0_12const_bufferEN11websocketpp19shared_const_bufferEEENS1_8write_opINS0_19basic_stream_socketINS0_2ip3tcpENS0_21stream_socket_serviceISB_EEEES6_NS1_14transfer_all_tENS_3_bi6bind_tIvNS_4_mfi3mf1IvNS5_4role6serverINS5_8endpointISL_NS5_6socket5plainENS5_3log6loggerEEEE10connectionINS5_10connectionISR_NSS_10connectionENSO_ISR_E10connectionEEEEERKNS_6system10error_codeEEENSG_5list2INSG_5valueINS_10shared_ptrISY_EEEEPFNS_3argILi1EEEvEEEEEEEE11do_completeEPNS1_15task_io_serviceEPNS1_25task_io_service_operationES13_j+0x1a8): undefined reference to `__sync_lock_test_and_set_4' echo_server.o: In function `boost::asio::detail::reactive_socket_send_op::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned int)': echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail23reactive_socket_send_opINS1_17consuming_buffersINS0_12const_bufferESt6vectorIS4_SaIS4_EEEENS1_8write_opINS0_19basic_stream_socketINS0_2ip3tcpENS0_21stream_socket_serviceISC_EEEES7_NS1_14transfer_all_tENS_3_bi6bind_tIvNS_4_mfi3mf1IvN11websocketpp10connectionINSL_8endpointINSL_4role6serverENSL_6socket5plainENSL_3log6loggerEEENSP_ISU_E10connectionENSR_ISU_E10connectionEEERKNS_6system10error_codeEEENSH_5list2INSH_5valueINS_10shared_ptrISZ_EEEEPFNS_3argILi1EEEvEEEEEEEE11do_completeEPNS1_15task_io_serviceEPNS1_25task_io_service_operationES13_j+0x208): undefined reference to `__sync_lock_test_and_set_4' echo_server.o: In function `boost::asio::detail::epoll_reactor::descriptor_state::perform_io(unsigned int)': echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail13epoll_reactor16descriptor_state10perform_ioEj+0x244): undefined reference to `__sync_fetch_and_add_4' echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail13epoll_reactor16descriptor_state10perform_ioEj+0x324): undefined reference to `__sync_fetch_and_add_4' echo_server.o: In function `boost::asio::detail::epoll_reactor::descriptor_state::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned int)': echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail13epoll_reactor16descriptor_state11do_completeEPNS1_15task_io_serviceEPNS1_25task_io_service_operationERKNS_6system10error_codeEj+0x21c): undefined reference to `__sync_fetch_and_add_4' echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail13epoll_reactor16descriptor_state11do_completeEPNS1_15task_io_serviceEPNS1_25task_io_service_operationERKNS_6system10error_codeEj+0x340): undefined reference to `__sync_fetch_and_add_4' echo_server.o: In function `boost::asio::detail::reactive_socket_recv_op::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned int)': echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail23reactive_socket_recv_opINS0_17mutable_buffers_1ENS1_26read_until_delim_string_opINS0_19basic_stream_socketINS0_2ip3tcpENS0_21stream_socket_serviceIS7_EEEESaIcENS_3_bi6bind_tIvNS_4_mfi3mf2IvN11websocketpp4role6serverINSG_8endpointISI_NSG_6socket5plainENSG_3log6loggerEEEE10connectionINSG_10connectionISO_NSP_10connectionENSL_ISO_E10connectionEEEEERKNS_6system10error_codeEjEENSC_5list3INSC_5valueINS_10shared_ptrISV_EEEEPFNS_3argILi1EEEvEPFNS17_ILi2EEEvEEEEEEEE11do_completeEPNS1_15task_io_serviceEPNS1_25task_io_service_operationES10_j+0x13c): undefined reference to `__sync_lock_test_and_set_4' echo_server.o: In function `boost::asio::detail::reactive_socket_recv_op::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned int)': echo_server.cpp:(.gnu.linkonce.t._ZN5boost4asio6detail23reactive_socket_recv_opINS0_17mutable_buffers_1ENS1_17read_streambuf_opINS0_19basic_stream_socketINS0_2ip3tcpENS0_21stream_socket_serviceIS7_EEEESaIcENS1_19transfer_at_least_tENS_3_bi6bind_tIvNS_4_mfi3mf1IvN11websocketpp10connectionINSH_8endpointINSH_4role6serverENSH_6socket5plainENSH_3log6loggerEEENSL_ISQ_E10connectionENSN_ISQ_E10connectionEEERKNS_6system10error_codeEEENSD_5list2INSD_5valueINS_10shared_ptrISV_EEEEPFNS_3argILi1EEEvEEEEEEEE11do_completeEPNS1_15task_io_serviceEPNS1_25task_io_service_operationESZ_j+0x104): undefined reference to `__sync_lock_test_and_set_4' echo_server.o: In function `websocketpp::message::intrusive_ptr_release(websocketpp::message::data const*)': echo_server.cpp:(.gnu.linkonce.t._ZN11websocketpp7message21intrusive_ptr_releaseEPKNS0_4dataE+0x34): undefined reference to `__sync_fetch_and_add_4' echo_server.cpp:(.gnu.linkonce.t._ZN11websocketpp7message21intrusive_ptr_releaseEPKNS0_4dataE+0x114): undefined reference to `__sync_fetch_and_add_4' echo_server.cpp:(.gnu.linkonce.t._ZN11websocketpp7message21intrusive_ptr_releaseEPKNS0_4dataE+0x244): undefined reference to `__sync_fetch_and_add_4' echo_server.o: In function `std::deque::_M_push_back_aux(boost::intrusive_ptr const">On Fri 17/02/12 07:01 , "Andreas Wehrmann" a.wehrmann(a)centersystems.com sent: On 02/16/2012 10:06 AM, Jayne wrote: > > Hello, > > I'm trying to build Boost 1.48.0 for use with the WebSockets++ library > on a MIPS based embedded Linux board. > > My build machine reports itself as: Linux version 2.6.40.4-5.fc15.x86_64 > (mockbuild(a)x86-10.phx2.fedoraproject.org) (gcc version 4.6.0 20110603 > (Red Hat 4.6.0-10) (GCC) ) #1 SMP Tue Aug 30 14:38:32 UTC 2011 > > My cross-compiler version is: mipsel-linux-g++ (GCC) 4.2.0 20070124 > (prerelease) - BRCM 11ts-20090508. I don't have any control over this as > its provided by the chip manufacturer. > > I can build Boost without any reported errors and can link to and use > most of the libraries without any problems. However, when WebSockets > tries to link to the Boost::asio library I get link errors like this: > > (.gnu.linkonce.t._ZNSt5dequeIN5boost13intrusive_ptrIN11websocketpp7message4dataEEESaIS5_EE16_M_push_back_auxERKS5_+0x30): > undefined reference to `__sync_add_and_fetch_4' > > (.gnu.linkonce.t._ZNSt5dequeIN5boost13intrusive_ptrIN11websocketpp7message4dataEEESaIS5_EE16_M_push_back_auxERKS5_+0x80): > undefined reference to `__sync_add_and_fetch_4' > > (.gnu.linkonce.t._ZN11websocketpp9processor4hybiINS_10connectionINS_8endpointINS_4role6serverENS_6socket5plainENS_3log6loggerEEENS5_ISA_E10connectionENS7_ISA_E10connectionEEEE19prepare_close_frameEN5boost13intrusive_ptrINS_7message4dataEEENS_5close6status5valueERKSs+0xc8): > more undefined references to `__sync_add_and_fetch_4' follow > > I've done enough research to find this has been a problem in the past > with ARM chips and is to do with atomic transactions not being > implemented by gcc for the target machine. I've tried the suggested > fixes for ARM which were to build with either BOOST_SP_DISABLE_THREADS > or BOOST_SP_USE_PTHREADS but that didn't help with my MIPS environment. > > Can anyone make any suggestions as to what I could try next? > > thanks, > > Jayne. > Try this #define: BOOST_ASIO_DISABLE_FENCED_BLOCK -- Dipl.-Ing. (FH) Andreas Wehrmann Software Development -------------------------------------------------------------- Center Communication Systems GmbH Sitz in Wien FN 796 88p, Firmenbuchgericht Wien http://www.centersystems.com [1]">www.centersystems.com Tel.: +43 (0) 190 199 - 3616 Mobile: +43 (0) 664 884 75916 Fax: +43 (0) 190 199 - 2110 E-Mail: a.wehrmann(a)centersystems.com _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users [2]">http://lists.boost.org/mailman/listinfo.cgi/boost-users Links: ------ [1] http://www.centersystems.com [2] http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Remove certificate from asio::ssl::context
by Lloyd 17 Feb '12

17 Feb '12

Hi, I am using a "single context object" loaded with necessary certificates, for a SSL based communication in the server side. The certificates are loaded with the call "use_certificate_file()". Is there any way that I can remove a certificate from the context. If this is not possible, is there any possibility of clearing the context, and reloading only the new necessary certificates? Thanks, Lloyd

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[heap] Boost heap and default constructors for comparators
by Evan Driscoll 17 Feb '12

17 Feb '12

The Boost heap library (at least binomial and fibonacci heaps) requires a default constructor of its comparator in order to call 'pop()' on a heap. I ran into this because I was trying to use a std::binary_negate<> wrapper around another comparator: this has no default constructor. So it's pretty easy to work around; I just have to provide a custom version of binary_negate. However, is this intentional? Should it be fixed? The problem is a little strange; it only surfaces if you call the 'pop()' function of the heap. If you look at the error location, binomial_heap.hpp:831, it is // private constructor, just used in pop() explicit binomial_heap(node_list_type & child_list, size_type size): super_t(value_compare()) To wit, with 1.49 beta 1: #include <boost/heap/binomial_heap.hpp> using namespace boost::heap; struct cmp { # ifdef MAKE_DEFAULT_CONSTRUCTOR cmp() {} # endif cmp(int a) {} bool operator() (int a, int b) const { return a < b; } }; int main() { cmp c(1); binomial_heap<int, compare<cmp> > h(c); h.push(1); # ifdef CALL_POP h.pop(); # endif } Compiling with CALL_POP undefined works. Adding -DCALL_POP then causes a compiler error (the following from GCC 4.3.2, but also witnessed with MSVC10): boost_1_49_0_beta1/boost/heap/binomial_heap.hpp: ... heap.cpp:21: instantiated from here boost_1_49_0_beta1/boost/heap/binomial_heap.hpp:831: error: no matching function for call to ‘cmp::cmp()’ heap.cpp:9: note: candidates are: cmp::cmp(int) heap.cpp:5: note: cmp::cmp(const cmp&) Adding -DMAKE_DEFAULT_CONSTRUCTOR works again.

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Can boost be compiled on WinCE?
by Luke Walker 17 Feb '12

17 Feb '12

Hi,I'm required to compile existing code on WinCE that uses boost::asio, boost::thread, boost::system and boost::spirit (wide strings). I attempted this and made allot of progress but eventually ran into so many dead-ends (locale, wide strings, etc, etc) that I had to quit and make this post. My questions are: Can these 4 libraries be compiled and used on WinCE? I'm not seeking a theoretical answer but rather "Has this been accomplished?". After scouring google, etc for two days straight have not found any reference to any person that actually compiled and got boost working on WinCE. I did however find plenty of evidence that it's being "attempted". Most of the posts remain unanswered. I would appreciate some help here. Thanks and take care.

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