October 2009 - Boost-users - lists.preview.boost.org

[Proto] proto::function and constness
by Kim Kuen Tang 12 Oct '09

12 Oct '09

Hi all, let _o_ be any proto terminal and v a vector. I would like to extract the vector v from the expression _o_(v) to do some modification on this vector. For this purpose i defined a grammar Rhs to extract the most right hand side of the tree. But unfortunately the compiler is asking me for constness for this code: boost::result_of<Rhs(Expr)>::type & result = Rhs()(expr); Whereas the expression _o_ + v compiles fine without asking me for constness. Am I missing something? Best regards, Kim Here is the code to demonstrate the problem. # include <vector> # include <iostream> # include <algorithm> # include <boost/proto/proto.hpp> namespace proto = boost::proto; namespace mpl = boost::mpl; using proto::_; template<typename Expr> struct MixedExpr; struct MixedDomain : proto::domain<proto::generator<MixedExpr> > {}; template<typename Expr> struct MixedExpr : proto::extends<Expr, MixedExpr<Expr>, MixedDomain> { explicit MixedExpr(Expr const &expr) : proto::extends<Expr, MixedExpr<Expr>, MixedDomain>(expr) {} }; struct oo { friend std::ostream &operator<<(std::ostream &s, oo const&) { return s << "oo"; } }; proto::terminal<oo>::type const _o_ = {{}}; template<typename T> struct IsMixed : mpl::false_ {}; template<typename T, typename A> struct IsMixed<std::vector<T, A> > : mpl::true_ {}; namespace MixedOps { BOOST_PROTO_DEFINE_OPERATORS(IsMixed,MixedDomain) }; namespace boost { namespace proto { template<typename T, typename A> std::ostream &operator<<(std::ostream &s, std::vector<T, A> const& ) { return s << "std::vector"; } }} struct Rhs : proto::or_< proto::when<proto::terminal<_>, proto::_value > ,proto::when<_, Rhs(proto::_child1)> > {}; template<typename Expr> void o_o(Expr& expr) { proto::display_expr(expr); boost::result_of<Rhs(Expr)>::type & result = Rhs()(expr); std::fill(result.begin(), result.end(),2); }; int main() { using namespace MixedOps; std::vector<int> u(10),v(10); //o_o( _o_(v) ); //uncomment this won't compile o_o( u+v ); std::copy(v.begin(),v.end(),std::ostream_iterator<int>(std::cout,",") ); std::cout<<std::endl; return 1; }

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graphlib changes in 1.40
by Ralph Gauges 12 Oct '09

12 Oct '09

Hi, I use the graph library in some of my programs and I recently moved to boost 1.40 because older version did not work on snow leopard. I noticed that although the changelog does not mention any changes in the graph library, some of the layout algorithms have changes (e.g. random layout and fruchterman reingold) in the way they are called. They seem to use some new topology concept, unfortunately the documentation for those algorithms have not been updated. I was wondering if there is any updated documentation especially on the fruchterman reingold algorithm. I tried to guess what the new parameters mean, but so far I have not been able to get the same results as with the graph library from 1.39. No matter how I set the values so far, all my nodes end up essentially in the same place, although they are all disconnected and I would expect them to be spread out. Thanks a lot Ralph

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boost-users@lists.boost.org
by hamidouche 12 Oct '09

12 Oct '09

hello I wanna build boost1_40 on a linux 64 machine (this is the my machine configuration) 2.6.28-11-generic #42-Ubuntu SMP Fri Apr 17 01:58:03 UTC 2009 x86_64 GNU/Linux compiler Intel 11.0 when I run ./bjam --toolset=intel I have this error message "icpc" -c -xc++ -O3 -w1 -inline-level=2 -pthread -fPIC -DBOOST_ALL_NO_LIB=1 -DBOOST_SERIALIZATION_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/serialization/build/intel-linux/release/threading-multi/basic_text_iprimitive.o" "libs/serialization/src/basic_text_iprimitive.cpp" ...failed intel-linux.compile.c++ bin.v2/libs/serialization/build/intel-linux/release/threading-multi/basic_text_iprimitive.o... intel-linux.compile.c++ bin.v2/libs/serialization/build/intel-linux/release/threading-multi/basic_text_oprimitive.o (0): internal error: backend signals compilation aborted for libs/serialization/src/basic_text_oprimitive.cpp (code 4) "icpc" -c -xc++ -O3 -w1 -inline-level=2 -pthread -fPIC -DBOOST_ALL_NO_LIB=1 -DBOOST_SERIALIZATION_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/serialization/build/intel-linux/release/threading-multi/basic_text_oprimitive.o" "libs/serialization/src/basic_text_oprimitive.cpp" ...failed intel-linux.compile.c++ bin.v2/libs/serialization/build/intel-linux/release/threading-multi/basic_text_oprimitive.o... intel-linux.compile.c++ bin.v2/libs/serialization/build/intel-linux/release/threading-multi/binary_iarchive.o (0): internal error: backend signals Please what wrong with this installing ? what should I change ?? Thanks

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Using fftw_complex with Boost.MultiArray?
by Rhys Ulerich 12 Oct '09

12 Oct '09

Has anyone successfully used FFTW's fftw_complex typedef[1] with Boost.MultiArray? Under the covers it is an array of length two, which seems to interact poorly with MultiArray's type assumptions. The attached test.cc fails to compile on g++ 4.3 and icpc 10.1. - Rhys [1] http://www.fftw.org/doc/Complex-numbers.html

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[xpressive] Shouldn't external placeholder variables allow consts?
by Ami Ganguli 12 Oct '09

12 Oct '09

I came across an interesting problem: what.let(_placeholder = this); fails to compile, because 'this' is a const pointer. A simple workaround: MyClass *_this = this; what.let(_placeholder = _this); But surely this shouldn't be necessary? Couldn't the right hand side of the let be declared const? Regards, Ami.

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[MPL] bitnot function??
by Sebastian Weber 12 Oct '09

12 Oct '09

Hi! I was wondering how come there is no bitwise not (~) operation in the mpl? Is there an equivalent statement? Thanks, Sebastian

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[asio] crash on io_service object destruction.
by Alexander Gutenev 12 Oct '09

12 Oct '09

Hi This is probably bug in my app, but I need an idea how to track it down. Seen on MSVC8, XP Occurs after io_service, which is processing many timers, sockets and posts in one thread is stopped from another thread. It is stopped fine, however it crashes on service object destruction at this line: // Delete the timer. void destroy() { destroy_func_(this); //// } destroy_func_ is often 0xfeeefeee, but sometimes it is 0x0 or any other value. Call stack is: boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::timer_base::destroy() Line 211 + 0xe bytes C++ boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::destroy_timer_list(boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::timer_base * & t=0x01acd090) Line 415 C++ boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::destroy_timers() Line 189 C++ boost::asio::detail::win_iocp_io_service::shutdown_service() Line 148 + 0x2c bytes C++ boost::asio::detail::service_registry::~service_registry() Line 75 + 0xf bytes C++ boost::asio::detail::service_registry::`scalar deleting destructor'() + 0x2b bytes C++ boost::asio::io_service::~io_service() Line 52 + 0x2e bytes C++ Any ideas ?

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How to delete the shared memory
by manish4gupta 12 Oct '09

12 Oct '09

Hi, I am working on shared memory and trying to delete the shared memory using ipcrm -m shmid command but it is not able to delete the shared memory. Even if I reboot my system, it does seem to be deleting the shared memory. I can not use sharedmemory:: remove function since i am not aware of shared memory region name now. Please help me. Thanks in advance. -- View this message in context: http://www.nabble.com/How-to-delete-the-shared-memory-tp25849509p25849509.h… Sent from the Boost - Users mailing list archive at Nabble.com.

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[units] newbie : plane_angle
by Damien R 11 Oct '09

11 Oct '09

Hi, I just discover boost::units and I want to know how it works in this case : quantity<si::plane_angle> angle(45 * degree); When the constructor is called, is the argument converted in radian or not ? Moreover, it is possible to have : quantity<??::plane_angle> angle(45 * degree); angle += pi / 4 * radian; cout << angle << endl; cout << quantity<degree::plane_angle>(angle) << endl; cout << quantity<radian::plane_angle>(angle) << endl; cout << angle.value<degree>() << endl; cout << angle.value<radian>() << endl; output : 45 deg + pi / 4 rad 90 deg pi / 2 rad 90 1.57079632679 Thanks. -- Damien R

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[shared_ptr] Using a custom delete function that is a class member function
by Ryan McConnehey 11 Oct '09

11 Oct '09

I have a class that provides a shared_ptr number. At the end of the number's life cycle it should be placed back on a list of available numbers. The shared_ptr's custom deleter function looks like what I need. I'm able to get a free function to compile as the deleter just fine. In trying to use a class member function as the custom deleter I've run into compile errors. I'm not sure where I'm going wrong. I know the custom deleter need to be copy constructible and I'm probably breaking some assumed requirement. Any help on what I'm doing wrong would be appreciated. Ryan class CTNGenerator { public: CTNGenerator(void) { m_AvailableCTNs.resize(20); unsigned short startValue = 15; for (ctns::iterator itor = m_AvailableCTNs.begin(); itor != m_AvailableCTNs.end(); ++itor) { //This compiles fine. boost::bind(boost::mem_fun(&CTNGenerator::makeCTNAvailable), this); //Placing the call as the custom delete function doesn't compile. *itor = bus(new unsigned short(startValue++), boost::bind(boost::mem_fun(&CTNGenerator::makeCTNAvailable, this))); } } private: void CTNGenerator::makeCTNAvailable(unsigned short * ctn) { m_AvailableCTNs.push_back(boost::shared_ptr<unsigned short>(ctn)); } private: typedef boost::shared_ptr<unsigned short> bus; typedef std::list<bus> ctns; ctns m_AvailableCTNs; };

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