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

[operators] equality_comparable
by Robert Jones 13 May '09

13 May '09

Given a template class like template < typename T > struct A { template < typename U > friend bool operator == ( const A &, const U & ); template < typename U > friend bool operator == ( const U &, const A & ); template < typename U > friend bool operator != ( const A &, const U & ); template < typename U > friend bool operator != ( const U &, const A & ); // ...other stuff... }; can I express it using equality_comparable? Thanks, Rob.

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[thread] mixing boost::mutex from different boost versions
by klaus triendl 13 May '09

13 May '09

Hi, are boost::mutexes from different boost versions ABI compatible, provided that the modules (boost thread library, my own) are compiled with the same compiler? My question arises because I'm creating a windows DLL with class methods taking a boost::mutex& from let's say boost 1.38, but an application (the EXE) might use e.g. boost 1.39. Klaus Triendl

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[asio] using ASIO with pcap_get_selectable_fd?
by Dustin Spicuzza 13 May '09

13 May '09

Hey, We're wanting to use Boost ASIO for doing socket operations and other asynchronous operations, but we also are using libpcap on multiple links. Currently, we're just getting fd's from pcap_get_selectable_fd() and using a select() loop to dispatch the loops when it's ready. Ideally, we want to use ASIO to do the select() part now instead of what we have, so theres less code to maintain. It seems like that if you add a descriptor to an io_service, you *have* to read or write some bytes to/from it, as opposed to just waiting for it to be ready (as libpcap wants). Is there a way to add an fd to an ASIO io_service and *not* read from it, but only call a routine when its ready to read? Thanks! Dustin -- Innovation is just a problem away

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[fusion][concept] sequence_base
by Pieter Op de Beeck 13 May '09

13 May '09

Hi all. I'm having difficulty understanding why the code listed below is not compiling (at least not on my box, gcc-4.3.2 / boost 1.38). (the code has been stripped and simplified for demonstration). Context: I have an interface and a model providing an implementation of this interface. I use a concept to make sure that the model provides a member function "foo" of a specific signature (whether doind it this way is useful or not, is not the point). In the example below, the member function "foo" should accept one parameter. This parameter should be of type "boost::fusion::sequence_base<SequenceT> const&". Except, when compiling the compiler informs me: invalid use of incomplete type ‘struct boost::fusion::extension::begin_impl<boost::fusion::non_fusion_tag>::apply<const boost::fusion::sequence_base<boost::fusion::list<int, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >’ Without the concept check in the interface class this compiles fine. Appreciating all your comments on this. Regards, Pieter. ======================main.cpp================================= #include <boost/concept/usage.hpp> #include <boost/concept/requires.hpp> #include <boost/fusion/support/sequence_base.hpp> #include <boost/fusion/container/generation.hpp> // simplified concept that requires from the model a member function 'foo' taking in a fusion:sequence_base template<class Model, typename SequenceT> struct concept { template <void (Model::*) (boost::fusion::sequence_base<SequenceT> const&) const> void model_requires_foo(); BOOST_CONCEPT_USAGE(concept) { model_requires_foo<&Model::foo>(); } }; // an interface which gives 'foo' taking in sequences template<class Model> class interface { public: template<typename SequenceT> BOOST_CONCEPT_REQUIRES( ((concept<Model, SequenceT>)), (void)) foo(SequenceT const& c) const { model_.foo(c); } private: Model model_; }; // a model that can handle fusion::sequence_base class model { public: template<typename SequenceT> void foo(boost::fusion::sequence_base<SequenceT> const& b) const { SequenceT const& sequence = b.derived(); } }; int main() { interface<model> bar; bar.foo(boost::fusion::make_list(1,2,3)); }; ==================end main.cpp==============================

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Boost Unit Tests on iPhone
by Manfred Schwind 13 May '09

13 May '09

Hi, I successfully built the boost libraries for the iPhone and for the iPhone Simulator. Now I have done some work on cross plattform C++ code and I am testing this code with Boost Unit Tests. It's running fine on Mac and Windows. It's also running fine on the iPhone Simulator. But unfortunately it's not working on the iPhone Device. It's not even getting into my test code, it just "hangs" somewhere before when collecting the test cases, if I can see this right in the debugger. I experienced that if I just have one BOOST_AUTO_TEST_CASE it also works fine on the iPhone Device. The test case executes, it succeeds and the app quits. But as soon as I have two or more BOOST_AUTO_TEST_CASEs, none of these test cases gets executed and the iPhone just hangs forever and loops around in some boost unit test initialization code using "spinlocks" and "yields" ... Is this a known issue? Anyone successfully using Boost Unit Tests on iPhone? Any ideas what I could try? Thanks, Mani -- http://mani.de - friendly software iVolume - listen to music freehand LittleSecrets - the encrypted notepad Sahara - sand in your pocket Watchdog - baffle the curious

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[fusion] mutable transform
by David Sankel 13 May '09

13 May '09

Hello, I'm using boost fusion to do some interesting robotics work. This has come up on the list before, but I'd like to point out my scenario where a mutable transform function would be useful. I'm writing a generic interface generator for various datatypes. For a given instance of the type, the interface generator return a widget that can modify the instance. I'd like my implementation for map types to look like this: //... for_each( transform( mapInstance , toWidget() ) , bind( Layout::addWidget, layout, _1 ) ); //... It has a very nice separation of concerns: 1) the "transform toWidget" function, and 2) the "for_each addWidget" which acts much like a fold. However, my toWidget function requires a non-const reference so this doesn't work without a hacky cast to remove the const. Hackery aside, the only way I know how do to this is using a for_each who's function argument explicity does both the conversion to a widget (with toWidget()) and the folding to the layout. Those two concepts seem separate to me. Maybe there's a better way or maybe I'm not understanding the drawbacks of exposing a mutable transpose function. Thanks, David -- David Sankel Sankel Software www.sankelsoftware.com

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PB with Regex Syntax in boost::regex 1.38 cause crash with memory exhausted .
by coord.admin 13 May '09

13 May '09

Hi , i'm using boost::regex 1.38 and C++ to code a textfile parsor . My code work correctly with most regular expression but i've got one problem with this expression: ^([^\s]+)\s+\d+\s+(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\s+\w+\/(\d+)\s+\d+\s+(\w+)\s+(\w+)\:\/\/?([^\:\/\?\s]+):?(\d*)(\S*).+Referer:(.+)\\r.*$ and a file with these lines : 1237084031.249 985 10.0.0.1 TCP_MISS/200 37567 GET http://monsite.information.com/index.mas?epl=00960031UlsNZ0sAVVETVRBeHgsJRz… - ROUNDROBIN_PARENT/10.10.10.10 text/html [Connection: Close\r\nCache-Control: no-cache,no-store\r\nPragma: No-Cache\r\nAccept: */*\r\nHost: monsite.information.com\r\nUser-Agent: XXXX/X.X (Update: XXXX X.X; UNIX)\r\nProxy-Connection: Keep-Alive\r\n] [HTTP/1.1 200 OK\r\nDate: Sun, 15 Mar 2009 02:27:10 GMT\r\nServer: Oversee Webserver v1.3.18\r\nSet-Cookie: ident=click:0%257csearch:0%257cexitpop:0%257ctoken:vqzyyyprxutxyvqs%257clload:0%257clvisit:1237084030; path=/; expires=Mon, 16-Mar-2009 02:27:10 GMT\r\nSet-Cookie: monsite.com=click:0%257csearch:0%257cexitpop:0%257clload:0%257clvisit:1237084030; path=/; expires=Mon, 16-Mar-2009 02:27:10 GMT\r\nSet-Cookie: Spusr=ac15000c6b3f49bc677e9c0b; path=/; expires=Tue, 15-Mar-11 02:27:10 GMT\r\nCache-control: private, no-cache, must-revalidate\r\nExpires: Mon, 26 Jul 1997 05:00:00 GMT\r\nPragma: no-cache\r\nP3P: policyref="http://monsite.information.com/w3c/p3p.xml", CP="NOI DSP COR ADMa OUR NOR STA"\r\nConnection: close\r\nContent-Type: text/html\r\n\r] I've got this error message : terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<std::runtime_error> >' what(): Memory exhausted Abandon The problem is probably here : (\d*)(\S*).+Referer:(.+) because when i delete this part it work correctly. I try this expression and this file with a perl script and it work correctly , but with boost not . Can you help me ?

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[conversion] lexical_cast<> compilation with --pedantic-errors
by Evgeny Tarasov 13 May '09

13 May '09

If to compile program with the key --pedantic-errors there exist some error messages. Otherwise everything is ok. #include <boost/lexical_cast.hpp> //line 38 In file included from /usr/local/include/boost-1_39/boost/detail/lcast_precision.hpp:16, from /usr/local/include/boost-1_39/boost/lexical_cast.hpp:31, from accepterimpl.cpp:38: /usr/local/include/boost-1_39/boost/integer_traits.hpp:164:66: use of C99 long long integer constant /usr/local/include/boost-1_39/boost/integer_traits.hpp:164:77: use of C99 long long integer constant /usr/local/include/boost-1_39/boost/integer_traits.hpp:170:70: use of C99 long long integer constant /usr/local/include/boost-1_39/boost/integer_traits.hpp:170:70: use of C99 long long integer constant make[2]: *** [accepterimpl.o] Error 1 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2 Are there any means to overcome it ?

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[BGL]Why the output of algorithms are vertex sequence(PredecessorMap)? How about parallel edges??
by Li Ning 13 May '09

13 May '09

For example, a graph has 2 nodes: A & B. There are 2 edges form A to B which are edge1 & edge2. edge1 has weight 1, edge2 has weight 2. Then the shortest path form A to B is: vertex A---edge1---vertex B. But the default output of all algorithm is vertex sequence. Why? How to get the edge sequence?? I have noticed vistor.hpp has a class edge_predecessor_recorder, but I don't know how to use it. Anybody give me a hint? -- View this message in context: http://www.nabble.com/-BGL-Why-the-output-of-algorithms-are-vertex-sequence… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Asio] Cancel an async timer from another timer's handler
by Laurent Fert 13 May '09

13 May '09

Hi, I faced some strange behavior while using timers (boost_1_38_0/boost_1_39_0). Here is an easy way to reproduce such behavior (note: I use async timeouts and a single thread): =experiment 1= Timer1 expires after 2 seconds and reschedules itself to fire again 2 seconds later. Timer2 expires after 2 seconds and cancels Timer1. Result: Timer2's handler gets called but the cancel call on Timer1 returns 0. Timer1's handler gets called (although it should have been cancelled) and therefore, Timer1 repeats itself indefinitely. =experiment 2= Timer1 expires after 1995 milliseconds and primes itself to fire again 1995 milliseconds later. Timer2 expires after 2 seconds and cancels Timer1. Result: Timer1's handler gets called and reschedules itself. Timer2's handler gets called and Timer1 gets canceled properly. =experiment 3= Timer1 expires after 2005 milliseconds and primes itself to fire again 2005 milliseconds later. Timer2 expires after 2 seconds and cancels Timer1. Result: Timer2's handler gets called and Timer1 gets canceled properly. =experiment 4= Repeat experiment 1 but change the expiration time of Timer1 instead of canceling it from Timer2's handler. Result: Timer2's handler gets called and Timer1 gets rescheduled properly. Note that Timer1's handler doesn't get called at all before the new expiry time although it should be called with an operation_aborted error code. =summary= When Timer1 and Timer2 expire at a very close time, Timer2 cannot cancel Timer1 although it can reschedule it. Is it an expected behavior? Is it due to the design of Asio? Regards, Laurent

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