October 2010 - Boost-users - lists.preview.boost.org

MSVC Visualizers Update
by Filip Konvička 28 Jul '11

28 Jul '11

Hi all, I've just updated the Boost visualizers wiki page at https://svn.boost.org/trac/boost/wiki/DebuggerVisualizers I updated the visualizer for Boost.MultiIndex, which did not work since Boost 1.35. I also added new visualizers for Boost.DateTime (ptime and time_duration) and a simple boost::shared_ptr visualizer. The visualizers are available for checkout via SVN at https://svn.boost.org/svn/boost/sandbox/boost_docs/subprojects/DebuggerVisu… Cheers, Filip

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[multi-array] Extracting dimension information from a multi-array
by Ryan McConnehey 15 Jul '11

15 Jul '11

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Asio unhandled exception
by Łukasz Majewski 20 May '11

20 May '11

Hello, I created a server single thread async (linux) and clinet (win). Every time client is close while server is writing to the socket connected to this client exception appears: terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::system::system_error>>' what(): Transport endpoint is not connected Aborted and server is terminated. I dont know why this exception is unhandled. int main( int argc, char** argv ) { try { boost::asio::io_service io_service; quotation_server server( io_service ); while ( true ) { try { io_service.run(); } catch( ... ){} } } catch ( std::exception& e ) { LOG << e.what() << std::endl; } catch( ... ) { LOG << "Unexpected exception" << std::endl; } return 0; }

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vs 2010 can't find correct boost lib version?
by Li, Tieniu 30 Mar '11

30 Mar '11

I built boost with visual studio 2010. Libraries of *-vc100-* are generated correctly. When trying to using boost.thread, VS 2010 generated error message: can't find *-vc90-*.lib. Any idea and fixing? Thanks a lot.

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[BGL] Separating twin vertices
by Shaun Jackman 19 Mar '11

19 Mar '11

Hi, I have a directed graph where every vertex has a twin vertex. It is known ahead of time which pairs of vertices are twins. I want to remove as few vertices as possible from the graph such that no vertex and its twin is in the same connected component. Could someone suggest an appropriate algorithm? I've just started delving into the BGL. So far I'm suitably impressed! Cheers, Shaun

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Simple serial port demonstration with boost asio asynchronous I/O
by Jeff Gray 26 Jan '11

26 Jan '11

A couple of weeks ago I posted a simple asynchronous demonstration of a telnet client using boost asio TCP network code. I have changed this code to turn it into a simple serial terminal application using the serial port support in the new version of boost asio. It required no changes at all the the read or write code. I just altered the initialization to use a serial port instead of a socket. Note that this is not intended to show how a fully functional application would work. There are plenty of areas that are not handled in this code. But it shows the idea and it's easy to build on this once you've got it working. Hope this helps someone else get started... Jeff

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[units] subtract_typeof_helper<> help!
by Terry Golubiewski 04 Jan '11

04 Jan '11

I'm trying to use boost::geometry and boost::units together. For some reason boost::geometry doesn't represent the difference of two points as vectors. So, I'm making my own Vector class and defining Vector = Point - Point. The sample program below doesn't compile because I need to tell the units library about the special properties of point subtraction (I think). terry #include <boost/geometry/geometry.hpp> #include <boost/units/systems/si.hpp> #include <boost/units/quantity.hpp> #include <boost/units/io.hpp> #include <iostream> #include <iomanip> using namespace std; using namespace boost; using namespace boost::geometry; using namespace boost::units; typedef point<double, 3, cs::cartesian> Point; class Vector { Point _impl; friend Vector operator-(const Point& lhs, const Point& rhs); explicit Vector(Point p) : _impl(p) { } public: Vector() : _impl(0) { } Vector(double dx, double dy, double dz=0) : _impl(dx, dy, dz) { } friend ostream& operator<<(ostream& os, const Vector& v) { return os << dsv(v._impl); } }; // Vector inline Vector operator-(const Point& lhs, const Point& rhs) { Point tmp(lhs); subtract_point(tmp, rhs); return Vector(tmp); } inline ostream& operator<<(ostream& os, const Point& pt) { return os << dsv(pt); } int main() { Point p1(1, 2, 3); Point p2(4, 5, 6); typedef quantity<si::length, Point> Position; typedef quantity<si::length, Vector> Displacement; Position start( p1 * si::meters); Position finish(p2 * si::meters); Displacement disp(finish - start); cout << "disp=" << disp << endl; return EXIT_SUCCESS; } // main

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Range - Char literal question
by Rao, Anant 10 Dec '10

10 Dec '10

Hi, I need to iterate thru strings (For various reasons, I can't use string or vector<char> containers). I found that boost::range exactly fits the bill for me. I get all the convenience of an iterator (from as_literal.hpp). I have a piece of code char* char_s = "I am fine"; char *cp; std::size_t sz = strlen(char_s); const char* str_end1 = str_begin( char_s ) + sz; for (cp = str_begin(char_s); cp != str_end(char_s); ++cp) cout << *cp; I have couple of questions: 1. In the loop, boost::range seems to be calling strlen every iteration. This is an overhead. I was wondering if there's a way I can pass in the length myself so that boost::range would use it and avoid calling strlen(). 2. If it's not possible, is there a way for me to use iterators (boost or non-boost) over char strings? Thanks so much in advance for your help, Anant The information contained in this email message and its attachments is intended only for the private and confidential use of the recipient(s) named above, unless the sender expressly agrees otherwise. Transmission of email over the Internet is not a secure communications medium. If you are requesting or have requested the transmittal of personal data, as defined in applicable privacy laws by means of email or in an attachment to email, you must select a more secure alternate means of transmittal that supports your obligations to protect such personal data. If the reader of this message is not the intended recipient and/or you have received this email in error, you must take no action based on the information in this email and you are hereby notified that any dissemination, misuse or copying or disclosure of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by email and delete the original message.

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[statechart] optional<event> - warning
by Igor R 07 Dec '10

07 Dec '10

Hello, When I define optional<my_event>, I get a warning (MSVC10): warning C4291: 'void *boost::statechart::event<MostDerived>::operator new(size_t,void *)' : no matching operator delete found; memory will not be freed if initialization throws an exception In class statechart::event I see 2 overloads of operator new: void * operator new( std::size_t size ) void * operator new( std::size_t, void * p ) But only 1 operator delete: void operator delete( void * pEvent ) i.e., no placement delete. Is this intentional? Thanks.

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Usage of Boost.Optional
by John Dlugosz 29 Nov '10

29 Nov '10

I have a situation where 'optional' is a good fit. However, I can't quite figure out how to use it for what I want. It appears to be geared around passing and returning instances, but I want to use it as a member. Consider: class C { D* d; // ... real code has much more stuff, naturally public: D(params) : d(0) { // ... if (I_ended_up_needing_d) d= new D (blahblah); // ... } ~D() { delete d; // harmless if zero } }; There is a single ownership of d by the instance, and it is not polymorphic but an exact type known at compile time. Making it a pointer adds overhead of using the heap, makes it harder to write EH-safe code for the constructor in more realistic situations, and requires adding explicit code to the destructor. Using a smart pointer only adds overhead, might take care of the EH and housekeeping, but still uses the heap. The 'optional' class provides for in-place storage, which it can use for an initialized instance, or it could be nil. That's exactly what I want. But, how do I tell optional<D> to construct at some point within the 'if' statement of my code? Assigning requires duplicating the object, and this type is not meant to be copied and has copy constructing and assignment disabled. Based on how the class works, I should be able to say "turn it on, now" and use an in-place factory. But the function to do that is not present in the class. class C { optional<D> d; public: D(params) : d(boost::none_t) { if (I_ended_up_needing_d) d.reset (in_place(blahblah)); } }; Am I missing something, or is the class missing something? I'm using Boost 1.43 in the project, and basing the above on the documentation for that version. The 'news' for 1.44 does not list Optional as having changed. Thanks, --John (sorry about the corporate footer) TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

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