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[ asio ] how to determine if a server is overloaded ?
by Avi Bahra 06 Jan '11

06 Jan '11

I am experimenting with boost asio & serialisation. and have created a test server based on the corresponding example in the asio tutorial. This is a simple single threaded server. The stress testing I have done, shows I get different results on different platforms. This is expected. However I need a way of determining when the server can not cope with the load. This allows me to inform the user. Currently I have used typical requests to stress test the server. This shows the server handles ~1000 requests/sec in debug under ideal conditions, on localhost. Does this means that if I continue to receive 1000/request sec over a several sec/minutes, then the server must be overloaded. Is this the right way of thinking about the problem or am I "barking up the wrong tree". Can any one provide any insights about how one goes about determining when a asio server is overloaded ? Any help appreciated. Best regards, Ta, Avi

2 1

transform_iterator::reference
by Matwey V. Kornilov 06 Jan '11

06 Jan '11

Hi, Boost 1.42.0 documentation of transfrom_iterator says: "If Reference is use_default then the reference member of transform_iterator is result_of<UnaryFunction(iterator_traits<Iterator>::reference)>::type. Otherwise, reference is Reference." But it is simply implemented as UnaryFunction::result_type; This discrepancy between documentation and implementation plays a role when I want to use transform_iterator with boost::mem_fn to access member variable of structure. mem_fn's operator() is overridden to provide both const and non-const access to member variable. The discrepancy leads to compilation error for non-const access.

2 2

[FunctionTypes] function_arity for non-built-ins
by Hossein Haeri 06 Jan '11

06 Jan '11

Dear all, How can I calculate the arity of function-objects? Obviously, function_arity won't do the job for that's only for built-ins. For instance, I need something like: function_types::function_object_arity<std::plus<double> >::value Anything in Boost for that? TIA, --Hossein

4 5

[Proto] result_of::value
by Hossein Haeri 06 Jan '11

06 Jan '11

Dear all, I have a piece of code in which contains: template<typename L, typename R> void FuncStreamCtx::operator () (tag::shift_right, const L& l, const R& r) const { evaluate_helper(l, *this); const typename result_of::value<R>::type f = value(r); } When I compile this under GCC 4.5.1 (MinGW, WinXP, SP3), I get a large spew of warnings. My related piece of code which I guess would be helpful is: double plus1(double i) {return i + 1;} double plus2(double i) {return i + 2;} struct FuncStreamCtx: callable_context<const FuncStreamCtx, null_context> { FuncStreamCtx() {} typedef void result_type; void operator () (tag::terminal, double) const; template<typename L, typename R> void operator () (tag::shift_right, const L&, const R&) const; const vector<double>& state() const {return data_;} private: void set_single_value(double) const; mutable vector<double> data_; }; template<typename Expr> const vector<double>& evaluate_helper(const Expr& e, const FuncStreamCtx& ctx) { boost::proto::eval(e, ctx); return ctx.state(); } template<typename Expr> void evaluate(const Expr& e, vector<double>& v) { const FuncStreamCtx ctx; v = evaluate_helper(e, ctx); } template<typename L, typename R> void FuncStreamCtx::operator () (tag::shift_right, const L& l, const R& r) const { evaluate_helper(l, *this); const typename result_of::value<R>::type f = value(r); } int main() { vector<double> v; evaluate(lit(51.6) >> &plus2 >> &plus2 >> &plus1, v); cout << "Result = "; copy(v.begin(), v.end(), ostream_iterator<double>(cout, " ")); return 0; } I have also included the warnings in the P.S. Any idea what the compiler is saying? And, should I do anything about it? TIA, --Hossein P.S. -------------- Build: Debug in ProtoGame3 --------------- Compiling: main.cpp D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp: In member function 'void FuncStreamCtx::operator()(boost::proto::tag::shift_right, const L&, const R&) const [with L = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, R = boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l>]': D:\Sources\Boost\boost_1_42_0/boost/proto/context/callable.hpp:313:21: instantiated from 'boost::proto::context::callable_eval<Expr, Context, 2l>::result_type boost::proto::context::callable_eval<Expr, Context, 2l>::operator()(Expr&, Context&) const [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = const FuncStreamCtx, boost::proto::context::callable_eval<Expr, Context, 2l>::result_type = void]' D:\Sources\Boost\boost_1_42_0/boost/proto/eval.hpp:100:62: instantiated from 'typename boost::proto::result_of::eval<Expr, Context>::type boost::proto::eval(Expr&, const Context&) [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = FuncStreamCtx, typename boost::proto::result_of::eval<Expr, Context>::type = void]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:44:2: instantiated from 'const std::vector<double>& evaluate_helper(const Expr&, const FuncStreamCtx&) [with Expr = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:52:2: instantiated from 'void evaluate(const Expr&, std::vector<double>&) [with Expr = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:80:53: instantiated from here D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:74:43: warning: unused variable 'f' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp: In member function 'void FuncStreamCtx::operator()(boost::proto::tag::shift_right, const L&, const R&) const [with L = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, R = boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l>]': D:\Sources\Boost\boost_1_42_0/boost/proto/context/callable.hpp:313:21: instantiated from 'boost::proto::context::callable_eval<Expr, Context, 2l>::result_type boost::proto::context::callable_eval<Expr, Context, 2l>::operator()(Expr&, Context&) const [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = const FuncStreamCtx, boost::proto::context::callable_eval<Expr, Context, 2l>::result_type = void]' D:\Sources\Boost\boost_1_42_0/boost/proto/eval.hpp:100:62: instantiated from 'typename boost::proto::result_of::eval<Expr, Context>::type boost::proto::eval(Expr&, const Context&) [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = FuncStreamCtx, typename boost::proto::result_of::eval<Expr, Context>::type = void]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:44:2: instantiated from 'const std::vector<double>& evaluate_helper(const Expr&, const FuncStreamCtx&) [with Expr = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:73:2: instantiated from 'void FuncStreamCtx::operator()(boost::proto::tag::shift_right, const L&, const R&) const [with L = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, R = boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l>]' D:\Sources\Boost\boost_1_42_0/boost/proto/context/callable.hpp:313:21: instantiated from 'boost::proto::context::callable_eval<Expr, Context, 2l>::result_type boost::proto::context::callable_eval<Expr, Context, 2l>::operator()(Expr&, Context&) const [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = const FuncStreamCtx, boost::proto::context::callable_eval<Expr, Context, 2l>::result_type = void]' D:\Sources\Boost\boost_1_42_0/boost/proto/eval.hpp:100:62: instantiated from 'typename boost::proto::result_of::eval<Expr, Context>::type boost::proto::eval(Expr&, const Context&) [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = FuncStreamCtx, typename boost::proto::result_of::eval<Expr, Context>::type = void]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:44:2: instantiated from 'const std::vector<double>& evaluate_helper(const Expr&, const FuncStreamCtx&) [with Expr = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:52:2: instantiated from 'void evaluate(const Expr&, std::vector<double>&) [with Expr = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:80:53: instantiated from here D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:74:43: warning: unused variable 'f' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp: In member function 'void FuncStreamCtx::operator()(boost::proto::tag::shift_right, const L&, const R&) const [with L = boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>, R = boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l>]': D:\Sources\Boost\boost_1_42_0/boost/proto/context/callable.hpp:313:21: instantiated from 'boost::proto::context::callable_eval<Expr, Context, 2l>::result_type boost::proto::context::callable_eval<Expr, Context, 2l>::operator()(Expr&, Context&) const [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = const FuncStreamCtx, boost::proto::context::callable_eval<Expr, Context, 2l>::result_type = void]' D:\Sources\Boost\boost_1_42_0/boost/proto/eval.hpp:100:62: instantiated from 'typename boost::proto::result_of::eval<Expr, Context>::type boost::proto::eval(Expr&, const Context&) [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = FuncStreamCtx, typename boost::proto::result_of::eval<Expr, Context>::type = void]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:44:2: instantiated from 'const std::vector<double>& evaluate_helper(const Expr&, const FuncStreamCtx&) [with Expr = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:73:2: instantiated from 'void FuncStreamCtx::operator()(boost::proto::tag::shift_right, const L&, const R&) const [with L = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, R = boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l>]' D:\Sources\Boost\boost_1_42_0/boost/proto/context/callable.hpp:313:21: instantiated from 'boost::proto::context::callable_eval<Expr, Context, 2l>::result_type boost::proto::context::callable_eval<Expr, Context, 2l>::operator()(Expr&, Context&) const [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = const FuncStreamCtx, boost::proto::context::callable_eval<Expr, Context, 2l>::result_type = void]' D:\Sources\Boost\boost_1_42_0/boost/proto/eval.hpp:100:62: [ skipping 2 instantiation contexts ] D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:73:2: instantiated from 'void FuncStreamCtx::operator()(boost::proto::tag::shift_right, const L&, const R&) const [with L = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, R = boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l>]' D:\Sources\Boost\boost_1_42_0/boost/proto/context/callable.hpp:313:21: instantiated from 'boost::proto::context::callable_eval<Expr, Context, 2l>::result_type boost::proto::context::callable_eval<Expr, Context, 2l>::operator()(Expr&, Context&) const [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = const FuncStreamCtx, boost::proto::context::callable_eval<Expr, Context, 2l>::result_type = void]' D:\Sources\Boost\boost_1_42_0/boost/proto/eval.hpp:100:62: instantiated from 'typename boost::proto::result_of::eval<Expr, Context>::type boost::proto::eval(Expr&, const Context&) [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>, Context = FuncStreamCtx, typename boost::proto::result_of::eval<Expr, Context>::type = void]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:44:2: instantiated from 'const std::vector<double>& evaluate_helper(const Expr&, const FuncStreamCtx&) [with Expr = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:52:2: instantiated from 'void evaluate(const Expr&, std::vector<double>&) [with Expr = boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const double&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<double (* const&)(double)>, 0l> >, 2l>]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:80:53: instantiated from here D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:74:43: warning: unused variable 'f' Linking console executable: bin\Debug\ProtoGame3.exe Output size is 1.08 MB Process terminated with status 0 (0 minutes, 4 seconds) 1 errors, 3 warnings

2 4

Problems in CodeGear
by jose perez 06 Jan '11

06 Jan '11

Hello. I'm unable to compile boost in Embarcadero 2010 (CodeGear) version 0x621. My code is really simple: #include "boost/random/mersenne_twister.hpp" This produces this error: [BCC32 Error] mersenne_twister.hpp(63): E2299 Cannot generate template specialization from 'detail::disable_constructor<Engine,T>' in the line: BOOST_RANDOM_DETAIL_GENERATOR_CONSTRUCTOR(mersenne_twister, Generator, gen) { seed(gen); } I have preprocessed my .cpp in order to see if boost gets correctly self configured for CodeGear compiler. It does very well, because it enters into codegear.hpp. But the last checked version of the CodeGear compiler is 0x620, and my version is 0x621. I have tried to change this line: // versions check: // last known and checked version is 0x620 #if (__CODEGEARC__ > 0x621) and this one: // CodeGear C++ Builder 2010 #if (__CODEGEARC__ <= 0x621) / # define BOOST_NO_TYPENAME_WITH_CTOR // Cannot use typename keyword when making temporaries of a dependant type etc... so that the compiler ignores or enters those sections, but nothing changes. It seems slightly strange to me that version 0x620 and 0x621 are SO different that boost is unable to get compiled. This problem has raised when trying to compile my application with libLAS library, which uses guid.hpp (which uses mersenne_twister.hpp), and there are much more compiler errors than the one I am explaining here. I guess (and hope) they are part of the same problem. No problems arise with other boost modules like, for example, "boost/smart_ptr.hpp". Help will be appreciated. Thanks!

2 6

Why we are still using boost 1.37
by Robert Lupton the Good 06 Jan '11

06 Jan '11

>> But I'm curious to know why you are still using 1.42. Well, I'm still using 1.37 for a large astronomical software project (the LSST). To quote one of the developers: > There have been changes to boost::serialization between these two > versions that break our persistence code. The issues appear in test > segfaults for packages at the afw level and higher. We could presumably find the problem in our code (or what's changed in boost::serialization) but that's real work. It's easier to patch boost::gil 1.37 to work with gcc 4.4 (or was it 4.5)? R

2 1

Re: [Boost-users] [Proto] callable_context
by Hossein Haeri 05 Jan '11

05 Jan '11

Dear Erik, > > lit(1) >> &f >> &g >> &h > > > > So, what about this new one in Proto? > > Yes, that should be doable. OK, that's good news. Here is my attempt to get it done (assuming that we only pipe integers into series of functions): struct FuncStreamCtx: callable_context<const FuncStreamCtx> { FuncStreamCtx() {} typedef int result_type; int operator () (tag::terminal, int i) const {return i;} template<typename L, typename R> int operator () (tag::shift_right, const L& l, const R& r) const { int arg = eval<L, const FuncStreamCtx>(l, *this);//*** int (*f) (int) = value(r); return f(arg); } }; (I know you told me that contexts make life hard. But, I'm not still comfortable with transforms...) Now, when I try to compile this code (GCC 4.5.1, MinGW32, WinXP, SP3), I get the error in the P.S. for trying it with: cout << eval(lit(51) >> &plus2, ctx); >From what I understand, from line ***, GCC mistakenly thinks that I'm trying to instantiate eval<> and fails to find an appropriate ctor -- it only nags about finding the default and the copy one. Strangely enough, when I remove the template arguments from the same line, I get: error: missing template arguments before '(' token Any ideas? TIA, --Hossein P.S. -------------- Build: Debug in ProtoGame3 --------------- Compiling: main.cpp D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp: In member function 'int FuncStreamCtx::operator()(boost::proto::tag::shift_right, const L&, const R&) const [with L = boost::proto::utility::literal<const int&, boost::proto::domainns_::default_domain>, R = boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int (* const&)(int)>, 0l>]': D:\Sources\Boost\boost_1_42_0/boost/proto/context/callable.hpp:313:21: instantiated from 'boost::proto::context::callable_eval<Expr, Context, 2l>::result_type boost::proto::context::callable_eval<Expr, Context, 2l>::operator()(Expr&, Context&) const [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const int&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int (* const&)(int)>, 0l> >, 2l>, Context = const FuncStreamCtx, boost::proto::context::callable_eval<Expr, Context, 2l>::result_type = int]' D:\Sources\Boost\boost_1_42_0/boost/proto/eval.hpp:100:62: instantiated from 'typename boost::proto::result_of::eval<Expr, Context>::type boost::proto::eval(Expr&, const Context&) [with Expr = const boost::proto::exprns_::expr<boost::proto::tag::shift_right, boost::proto::argsns_::list2<const boost::proto::utility::literal<const int&, boost::proto::domainns_::default_domain>&, boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int (* const&)(int)>, 0l> >, 2l>, Context = FuncStreamCtx, typename boost::proto::result_of::eval<Expr, Context>::type = int]' D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:38:37: instantiated from here D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame3\main.cpp:23:50: error: no matching function for call to 'boost::proto::context::callable_context<const FuncStreamCtx>::eval<boost::proto::utility::literal<const int&, boost::proto::domainns_::default_domain> >::eval(const boost::proto::utility::literal<const int&, boost::proto::domainns_::default_domain>&, const FuncStreamCtx&)' D:\Sources\Boost\boost_1_42_0/boost/proto/context/callable.hpp:223:17: note: candidates are: boost::proto::context::callable_context<const FuncStreamCtx>::eval<boost::proto::utility::literal<const int&, boost::proto::domainns_::default_domain> >::eval() D:\Sources\Boost\boost_1_42_0/boost/proto/context/callable.hpp:223:17: note: boost::proto::context::callable_context<const FuncStreamCtx>::eval<boost::proto::utility::literal<const int&, boost::proto::domainns_::default_domain> >::eval(const boost::proto::context::callable_context<const FuncStreamCtx>::eval<boost::proto::utility::literal<const int&, boost::proto::domainns_::default_domain> >&) Process terminated with status 1 (0 minutes, 19 seconds) 3 errors, 0 warnings

1 1

Boost.Iostreams devices and unsigned char character types
by laanan fisher 05 Jan '11

05 Jan '11

Hi, I'm having some trouble using boost::iostreams::basic_file (and other devices) with unsigned char character types. It's likely a lack of understanding on my part, so any help is greatly appreciated. Here is what I'd like to do, and the results from my g++ v4.5.0 compilation. Thanks for your time. # include <boost/iostreams/device/file.hpp> # include <boost/iostreams/get.hpp> int main() { namespace io = boost::iostreams; io::basic_file_source< unsigned char > file( "us.cpp" ); int ch = io::get( file ); return 0; } /* In file included from d:/boost_1_45_0/boost/iostreams/detail/adapter/non_blockin g_adapter.hpp:12:0, from d:/boost_1_45_0/boost/iostreams/close.hpp:19, from d:/boost_1_45_0/boost/iostreams/operations.hpp:16, from d:/boost_1_45_0/boost/iostreams/device/file.hpp:23, from us.cpp:1: d:/boost_1_45_0/boost/iostreams/read.hpp: In static member function 'static type name boost::iostreams::int_type_of<T>::type boost::iostreams::detail::read_devic e_impl<boost::iostreams::input>::get(T&) [with T = boost::iostreams::basic_file_ source<unsigned char>, typename boost::iostreams::int_type_of<T>::type = long un signed int]': d:/boost_1_45_0/boost/iostreams/read.hpp:47:60: instantiated from 'typename bo ost::iostreams::int_type_of<T>::type boost::iostreams::get(T&) [with T = boost:: iostreams::basic_file_source<unsigned char>, typename boost::iostreams::int_type _of<T>::type = long unsigned int]' us.cpp:10:28: instantiated from here d:/boost_1_45_0/boost/iostreams/read.hpp:180:42: error: incomplete type 'boost:: iostreams::detail::read_device_impl<boost::iostreams::input>::get(T&) [with T = boost::iostreams::basic_file_source<unsigned char>, typename boost::iostreams::i nt_type_of<T>::type = long unsigned int]::traits_type' used in nested name speci fier d:/boost_1_45_0/boost/iostreams/read.hpp:180:42: error: incomplete type 'boost:: iostreams::detail::read_device_impl<boost::iostreams::input>::get(T&) [with T = boost::iostreams::basic_file_source<unsigned char>, typename boost::iostreams::i nt_type_of<T>::type = long unsigned int]::traits_type' used in nested name speci fier d:/boost_1_45_0/boost/iostreams/read.hpp:180:42: error: incomplete type 'boost:: iostreams::detail::read_device_impl<boost::iostreams::input>::get(T&) [with T = boost::iostreams::basic_file_source<unsigned char>, typename boost::iostreams::i nt_type_of<T>::type = long unsigned int]::traits_type' used in nested name speci fier */

2 1

Local_date_time constructor question
by qplace 05 Jan '11

05 Jan '11

Documentation for local_date_time constructor local_date_time(...) Parameters: date time_duration time_zone_ptr bool states that the last parameter, "The DST flag", "must be passed to indicate whether the time is in daylight savings or not." My question is: Isn't the combination of the first parameter, "date" and third parameter, "time_zone_ptr" determine if the resulted local_date_time will be either in the daylight saving time period or not?

3 3

filtering stream fpos
by Christian Meesters 05 Jan '11

05 Jan '11

Hi, is there something like fpos for boost's filtering streams? If so, I must have overlooked it in the docs. Or, if this fpos-thing does not work out: I would like to remember the position where I left a (potentially gzipped) file and resume work (reading only) on that file in subsequent function calls. Is this somehow possible? TIA Christian PS Happy New Year everybody! (Better late than never ...)

1 0