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Re: [Boost-users] [proto] generation of adaptive precision floating-point geometric predicates
by Kim Kuen Tang 22 Mar '10

22 Mar '10

Hi Andrew, just my thoughts on this chat. Andrew Durward schrieb: > > The central concept is that for any expression (a # b) where # is {+, -, *}, > the result can be expressed as (x + y) where x is the floating-point How about transform the expression a+b to sum_approx(a,b)+sum_diff(a,b) instead to fusion::cons<sum_approx(a,b),fusion::cons<sum_diff(a,b)> > ? The advantage of this approach is that you still get an ast where childs are held in terminal (instead in cons). > approximation of (a # b), and y is an error term whose value can also be > computed as a floating-point value. > > In toying with proto, I've been able to transform simple expressions > successfully but I can't seem to figure out how to define a grammar that > will handle arbitrary combinations of {+, -, *} recursively. Here's what > I've got so far: > > struct sum_approx{/* */}; > struct sum_error{/* */}; > > struct diff_approx{/* */}; > struct diff_error{/* */}; > > struct prod_approx{/* */}; > struct prod_error{/* */}; > > struct Transform : > proto::or_< > proto::when< > proto::plus< proto::terminal< _ >, proto::terminal< _ > > > , fusion::cons< > proto::_make_function( > sum_approx() > , proto::_left > , proto::_right > ) I dont see the meaning behind this step. If you use proto::_make_function you create a child in the ast, but you put this child in a fusion::cons. > , fusion::cons< > proto::_make_function( > sum_error() > , proto::_left > , proto::_right > ) > > > >() > > > // ... similar substitutions for minus and multiplies > > > {}; > > So the expression (a + b) yields the sequence: > sum_approx(a,b) > sum_error(a,b) > > Here's where I'm stuck. In the case of the expression (a + b)*(c - d), the > addition and subtraction should be replaced by the appropriate sequences > before the multiplication gets expanded to yield the final sequence: > prod_approx( sum_approx(a,b), diff_approx(c,d) ) > prod_error( sum_approx(a,b), diff_approx(c,d) ) > prod_approx( sum_approx(a,b), diff_error(c,d) ) > prod_error( sum_approx(a,b), diff_error(c,d) ) > prod_approx( sum_error(a,b), diff_approx(c,d) ) > prod_error( sum_error(a,b), diff_approx(c,d) ) > prod_approx( sum_error(a,b), diff_error(c,d) ) > prod_error( sum_error(a,b), diff_error(c,d) ) Are you sure that you want to get a sequence of expression instead an ast. In case you really want to get a sequence you can use proto::tag::comma to separate your child. > Obviously I need a recursive transform here but I'm not sure how to pass it > the sequences generated by both the left and right subtrees. > > Cheers, Kim Here is a toy project. Hth. # include <boost/cstdlib.hpp> # include <boost/proto/proto.hpp> # include <boost/fusion/container/list/cons.hpp> # include <boost/proto/tags.hpp> # include <boost/proto/make_expr.hpp> # define PRECISION_MAKE_tag(name) \ struct name \ { \ friend std::ostream& operator<< (std::ostream& s, name const&) \ { \ return s<< #name; \ } \ }; # define PRECISION_MAKE_terminal(name) \ proto::terminal< tag::name >::type const name = {{}} namespace proto = boost::proto; namespace tag{ PRECISION_MAKE_tag(a); PRECISION_MAKE_tag(b); PRECISION_MAKE_tag(c); PRECISION_MAKE_tag(d); PRECISION_MAKE_tag(sum_approx); PRECISION_MAKE_tag(sum_error); PRECISION_MAKE_tag(diff_approx); PRECISION_MAKE_tag(diff_error); } namespace mpl = boost::mpl; namespace fusion = boost::fusion; using proto::_; struct transform { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This,typename A0,typename A1> struct result<This(proto::tag::plus const,A0,A1)> : proto::result_of::make_expr< proto::tag::plus , typename proto::result_of::make_expr< proto::tag::function ,tag::sum_approx, A0, A1 >::type , typename proto::result_of::make_expr< proto::tag::function ,tag::sum_error, A0, A1 >::type > {}; template<typename This,typename A0,typename A1> struct result<This(proto::tag::minus const,A0,A1)> : proto::result_of::make_expr< proto::tag::minus, A0, A1 > {}; template<typename A0,typename A1> typename result<transform(proto::tag::plus const ,A0 const&, A1 const&)>::type operator()(proto::tag::plus const ,A0 const& a0,A1 const& a1) const { return proto::make_expr<proto::tag::plus>( proto::make_expr<proto::tag::function>( tag::sum_approx() , boost::ref(a0) , boost::ref(a1)) ,proto::make_expr<proto::tag::function>( tag::sum_error() , boost::ref(a0) , boost::ref(a1)) ); //return proto::make_expr<proto::tag::plus>(boost::ref(a0), boost::ref(a1)); }; template<typename A0, typename A1> typename result<transform(proto::tag::minus const ,A0 const&, A1 const&)>::type operator()(proto::tag::minus const ,A0 const& a0, A1 const& a1) const { return proto::make_expr<proto::tag::minus>(boost::ref(a0), boost::ref(a1)); }; }; struct Transform : proto::or_< proto::when< proto::plus< proto::terminal< _ >, proto::terminal< _ > > , transform( proto::tag::plus() , proto::_value(proto::_left) , proto::_value(proto::_right) ) > ,proto::when< proto::minus< proto::terminal< _ >, proto::terminal< _ > > , transform( proto::tag::minus() , proto::_value(proto::_left) , proto::_value(proto::_right) ) > , proto::otherwise<proto::nary_expr<_, proto::vararg<Transform> > > > {}; PRECISION_MAKE_terminal(a); PRECISION_MAKE_terminal(b); PRECISION_MAKE_terminal(c); PRECISION_MAKE_terminal(d); # undef PRECISION_MAKE_tag # undef PRECISION_MAKE_terminal int main() { proto::display_expr(a+b); BOOST_AUTO(expr, Transform()( (a+b)*(c-d) ) ); proto::display_expr(expr); return boost::exit_success; }

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Re: [Boost-users] [proto] generation of adaptive precision floating-point geometric predicates
by Manjunath Kudlur 22 Mar '10

22 Mar '10

> Here's where I'm stuck. In the case of the expression (a + b)*(c - d), the > addition and subtraction should be replaced by the appropriate sequences > before the multiplication gets expanded to yield the final sequence: See if the following works for you. I try to replace a # b with sum(#_approx(a,b), #_error(a,b)). The display_expr looked correct, but I didn't check very carefully. #include <boost/proto/proto.hpp> #include <iostream> namespace proto = boost::proto; using proto::_; unsigned ids = 0; struct var { unsigned id; var() { id = ids++; } friend std::ostream &operator<<(std::ostream &s, var v) { s << "V" << v.id; return s; } }; struct sum_approx { friend std::ostream &operator<<(std::ostream &s, sum_approx) { s << "sum_approx"; return s; } }; struct sum_error { friend std::ostream &operator<<(std::ostream &s, sum_error) { s << "sum_error"; return s; } }; struct diff_approx { friend std::ostream &operator<<(std::ostream &s, diff_approx) { s << "diff_approx"; return s; } }; struct diff_error { friend std::ostream &operator<<(std::ostream &s, diff_error) { s << "diff_error"; return s; } }; struct prod_approx { friend std::ostream &operator<<(std::ostream &s, prod_approx) { s << "prod_approx"; return s; } }; struct prod_error { friend std::ostream &operator<<(std::ostream &s, prod_error) { s << "prod_error"; return s; } }; struct sum { friend std::ostream &operator<<(std::ostream &s, sum) { s << "sum"; return s; } }; struct grammar : proto::or_< proto::when<proto::plus<grammar, grammar>, proto::_make_function(sum(), proto::_make_function(sum_approx(), grammar(proto::_left), grammar(proto::_right)), proto::_make_function(sum_error(), grammar(proto::_left), grammar(proto::_right)))> ,proto::when<proto::minus<grammar, grammar>, proto::_make_function(sum(), proto::_make_function(diff_approx(), grammar(proto::_left), grammar(proto::_right)), proto::_make_function(diff_error(), grammar(proto::_left), grammar(proto::_right)))> ,proto::when<proto::multiplies<grammar, grammar>, proto::_make_function(sum(), proto::_make_function(prod_approx(), grammar(proto::_left), grammar(proto::_right)), proto::_make_function(prod_error(), grammar(proto::_left), grammar(proto::_right)))> , proto::terminal<var> > {}; typedef proto::terminal<var>::type Var; int main() { Var a, b, c, d; proto::display_expr(grammar()( (a+b)*(c-d) )); }

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Will asio::ip::tcp::socket::read let me read all my data even if remote end is connected?
by Sean McAllister 22 Mar '10

22 Mar '10

Looking at the documentation for this function: http://www.boost.org/doc/libs/1_37_0/doc/html/boost_asio/reference/basic_st… I'm not entirely clear whether it will do what I want. Basically I'm going to be having a server send blocks of signal data (of unknown duration or length). I'd like the client to be able to read chunks of that until the remote end closes. So right now my API has the user pass in a memory buffer to fill along with a size and I repeatedly call socket::read to fill it up. What I'm curious about is if the server doesn't send a full block for the last block, and then closes the connection. Will this function still return whatever data it was able to read and then throw an exception on the next read? Or will it throw an exception on that last read, rendering the last bit of data inaccesible? Sean

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IOService.run()
by Iskandar Prins 22 Mar '10

22 Mar '10

Hi, I have a question regarding the asio::deadline_timer , it seems I need to run the ioservice.run() all the time in order to update the timer, which is seems undesirable. Any idea how I can just start the timer and wait for the callback instead? Regards, Iskandar Prins IT Software Developer Alphabay Capital B.V. Singel 540 1017AZ Amsterdam Tel: +31 (0)20 755 9642 Fax: +31 (0)20 755 9601 iprins(a)alphabay.nl

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Problems with copying view on mpl set on solaris compiler.
by Jonathan Chambers` 22 Mar '10

22 Mar '10

I'm trying to get the following to compile on solaris using S1S12u1; #include <boost/mpl/copy.hpp> #include <boost/mpl/set.hpp> #include <boost/type_traits.hpp> #include <boost/mpl/placeholders.hpp> #include <boost/mpl/inserter.hpp> #include <boost/mpl/insert.hpp> #include <boost/mpl/filter_view.hpp> typedef boost::mpl::copy< boost::mpl::filter_view< boost::mpl::set<int>, boost::is_same<boost::mpl::_, int> >, boost::mpl::inserter< boost::mpl::set<>, boost::mpl::insert<boost::mpl::_, boost::mpl::_> > >::type type; template <class undefined> struct Debug; Debug<type> debug; int main(int argc, char *argv[]) { return 0; } and I get the following compiler errors "boost_1_42_0/boost/mpl/aux_/filter_iter.hpp", line 66: Error: Redefining boost::mpl::next<boost::mpl::T> after use in boost::mpl::aux::filter_i ter<boost::mpl::s_iter<boost::mpl::set<int, char, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_ ::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::s_item<int, boost::mpl::set0<mpl_::na>>>, boo st::mpl::s_iter<boost::mpl::set<int, char, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, m pl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::set0<mpl_::na>>, boost::mpl::protect<boost::mpl::bin d2<boost::mpl::quote2<boost::is_same<boost::T, boost::U>, mpl_::void_>, mpl_::arg<-1>, int>, 0>>. "boost_1_42_0/boost/mpl/next_prior.hpp", line 31: Where: While specializing "boost::mpl::aux::filter_iter<boost::mpl::s_iter<boost::mpl::set <int, char, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mp l_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::s_item<int, boost::mpl::set0<mpl_::na>>>, boost::mpl::s_iter<boost::mpl::set<int, c har, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::set0<mpl_::na>>, boost::mpl::protect<boost::mpl::bind2<boost::mpl::quote2<boost::is_same<b oost::T, boost::U>, mpl_::void_>, mpl_::arg<-1>, int>, 0>>". "boost_1_42_0/boost/mpl/next_prior.hpp", line 31: Where: Specialized in boost::mpl::next<boost::mpl::aux::filter_iter<boost::mpl::s_iter<boo st::mpl::set<int, char, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::s_item<int, boost::mpl::set0<mpl_::na>>>, boost::mpl::s_iter<boost::mpl ::set<int, char, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::n a, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::set0<mpl_::na>>, boost::mpl::protect<boost::mpl::bind2<boost::mpl::quote2<boos t::is_same<boost::T, boost::U>, mpl_::void_>, mpl_::arg<-1>, int>, 0>>>. "boost_1_42_0/boost/mpl/aux_/preprocessed/plain/fold_impl.hpp", line 162: Where: Specialized in boost::mpl::aux::fold_impl<-1, boost::mpl::a ux::filter_iter<boost::mpl::s_iter<boost::mpl::set<int, char, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mp l_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::s_item<int, boost::mpl::set0<mpl_ ::na>>>, boost::mpl::s_iter<boost::mpl::set<int, char, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::set0<mpl_::na>>, boost::mpl::protect<boo st::mpl::bind2<boost::mpl::quote2<boost::is_same<boost::T, boost::U>, mpl_::void_>, mpl_::arg<-1>, int>, 0>>, boost::mpl::aux::filter_iter<boost ::mpl::s_iter<boost::mpl::set<int, char, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl _::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::set0<mpl_::na>>, boost::mpl::s_iter<boost::mpl::set<in t, char, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_: :na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::set0<mpl_::na>>, boost::mpl::protect<boost::mpl::bind2<boost::mpl::quote2<boost::is_sa me<boost::T, boost::U>, mpl_::void_>, mpl_::arg<-1>, int>, 0>>, boost::mpl::set<mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_ ::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost:: mpl::insert<mpl_::arg<-1>, mpl_::arg<-1>, mpl_::na>>. "boost_1_42_0/boost/mpl/fold.hpp", line 39: Where: Specialized in boost::mpl::fold<boost::mpl::filter_view<boost::mpl::set<int, char, mpl_:: na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::is_same<mpl_::arg<-1>, int>>, boost::mpl::set<mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boo st::mpl::insert<mpl_::arg<-1>, mpl_::arg<-1>, mpl_::na>>. "boost_1_42_0/boost/mpl/copy.hpp", line 36: Where: Specialized in boost::mpl::aux::copy_impl<boost::mpl::filter_view<boost::mpl::set<int, ch ar, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::is_same<mpl_::arg<-1>, int>>, boost::mpl::inserter<boost::mpl::set<mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl _::na, mpl_::na, mpl_::na>, boost::mpl::insert<mpl_::arg<-1>, mpl_::arg<-1>, mpl_::na>>>. "boost_1_42_0/boost/mpl/copy.hpp", line 54: Where: Specialized in boost::mpl::copy<boost::mpl::filter_view<boost::mpl::set<int, char, mpl_:: na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::is_same<mpl_::arg<-1>, int>>, boost::mpl::inserter<boost::mpl::set<mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl _::na, mpl_::na>, boost::mpl::insert<mpl_::arg<-1>, mpl_::arg<-1>, mpl_::na>>>. "filter_view.cpp", line 19: Where: Specialized in non-template code. "filter_view.cpp", line 24: Error: In this declaration "debug" is of an incomplete type "Debug<boost::mpl::s_item<int, boost::mpl::set0<mpl_::na >>>". 2 Error(s) detected. You can see by the debug that the program has managed to deduce the correct type, even though it errored. On GCC-4.1.1 this gives filter_view.cpp:24: error: aggregate 'Debug<boost::mpl::s_item<int, boost::mpl::set0<mpl_::na> > > debug' has incomplete type and cannot be defined Which is exactly what I want. Anyone else had these issues, found workarounds, etc? This problem also occurs with boost::mpl::transform_view, but appears to work for boost::mpl::joint_view. Any help appreciated. Jon. _________________________________________________________________ Send us your Hotmail stories and be featured in our newsletter http://clk.atdmt.com/UKM/go/195013117/direct/01/

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blocking read after async connect
by David Kaplan 22 Mar '10

22 Mar '10

I have a class that performs a timed connect (i.e. using an async connect that returns an error if connection failed/timed-out). However every asio::read/write performed on the socket after a successful async_connect fails. Any ideas? Is it impossible to perform read/write on such a socket? do I have to stop() the io service to put it back into synchronous mode?

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[fusion?] [Phoenix?] Calling arbitrary method with collection of args
by Nat Goodspeed 22 Mar '10

22 Mar '10

We have a data type equivalent to a recursive variant that can hold a few scalar types or a vector of such types. My colleague proposes that we build a template function that will accept a free function or class method (that is, any callable whose signature we can infer) plus a vector of the variant type. For each formal parameter type in the callable's signature, this function would ensure that the vector is long enough to fill it, and then that the runtime type of the appropriate vector entry is compatible with the static type of the parameter. Finally it would call the callable, filling the formal parameters from the variant vector. I strongly suspect that this function already exists in Boost. I simply don't know which library to research. (OvermindDL1?)

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undefined reference to `boost::program_options
by G.NAGENDAR 22 Mar '10

22 Mar '10

Hi, When i run my C++ program which is using boost library, i am getting these errors main.o: In function `boost::program_options::variables_map::operator[](std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const': /usr/local/include/boost-1_35/boost/program_options/variables_map.hpp:161: undefined reference to `boost::program_options::abstract_variables_map::operator[](std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const' /usr/local/include/boost-1_35/boost/program_options/variables_map.hpp:161: undefined reference to `boost::program_options::abstract_variables_map::operator[](std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const' /usr/local/include/boost-1_35/boost/program_options/variables_map.hpp:161: undefined reference to `boost::program_options::abstract_variables_map::operator[](std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const' /usr/local/include/boost-1_35/boost/program_options/variables_map.hpp:161: undefined reference to `boost::program_options::abstract_variables_map::operator[](std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const Please help to solve this problem. Please... -- Thanks & Regards Nagendar

2 2

Variant and Fusion
by Matthias Vallentin 21 Mar '10

21 Mar '10

Hi, there used to be a variant adapter for fusion sequences, but it has been rightfully removed: on Wed Dec 19 2007, Joel de Guzman <joel-AT-boost-consulting.com> wrote: > I intend to remove the variant adapter from fusion. After thorough > investigation, I think now that the move to make variant a > fusion sequence is rather quirky. A variant will always > have a size==1 regardless of the number of types it can contain > and there's no way to know at compile time what it contains. > Iterating over its types is simply wrong. All these imply that > the variant is *not* a fusion sequence. Let's say I have a recursive variant and would like to flatten the variant to create some sort of heterogeneous sequence from it. Particularly, I would like to chop the variant into multiple disjunct Fusion sequences, each of which are handed to generic component that operates with Fusion sequences. The above suggests that Fusion is not the right tool. What would be a better approach to handle this problem? Should I split the variant into smaller variants instead? What made Fusion so attractive is the notion of tiers, i.e., light-weight views of references to the actual data. Is there a variant equivalent of tiers? Matthias -- Matthias Vallentin vallentin(a)icsi.berkeley.edu http://www.icir.org/matthias

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Multithread event handling
by Alessandro Bellina 21 Mar '10

21 Mar '10

Hello boost, Traditionally, I think of services as having a thread pool or manually managed threads to handle requests and produce responses. I have been looking at boost::asio and tbb as an alternative to this in order to take advantage of multiple cores. Also, I think that implementing an event handler with asio or tbb should provide better performance over a threadpool. Do you have any suggestions? So far, I have implemented an example using tbb::task_group and spawned tasks. This yielded full CPU utilization, but since these are very short lived tasks, the task creation overhead took over. Using io_service, it seems to be as easy as posting to the service, and running it among different threads. Would this be the correct approach for my case? Can somebody share their experiences on libraries or patterns used to implement an event handling mechanism? Thanks, Alessandro

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