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multi_array move semantics
by MM 03 Feb '14

03 Feb '14

Hello, 1. Browsing the multi_array doc, there doesn't seem to be a move ctor? 2. Has there been any attempt to implement one? 3. if not, and the authors are reading this, are there any hints to help with this? Regards MM

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serialization: intrusive_ptr
by MM 03 Feb '14

03 Feb '14

Hello, I've found an implementation of a serializer for intrusive_ptr here: http://stellar.cct.lsu.edu/files/hpx_0.9.5/html/code/hpx/util/serialize_int… which i've injected into my boost lib. Hartmut Kaiser, I guess, would there be a proposal to add it serialization for future standard boost? Regards MM

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inter thread communication with message queues
by Kenneth Adam Miller 31 Jan '14

31 Jan '14

I was reading about message queues with respect to inter thread communication, and I have a specific use case that I want to describe. It's rather complex, so I want to be careful that I design it so that there are no race conditions. Pool A is a buffer (of type 1) handle manager, that feeds buffer handles into thread set 1, and receives old handles from thread set 2. There is only one thread running pool A. Thread set 1 is a set of N threads that fill up buffers of type 1 with regular data. It pushes full buffers to thread set 2. Thread set 2 is a set of M threads that compress buffers of type 1 into data buffers of type 2. Once the buffer of type 1 has be used up, it is cleared and sent back to Pool A. It pulls fresh data buffers of type 2 from Pool B, and sends freshly filled compressed buffers to Pool C. Pool C does something with the buffer, clears it and hands it to Pool B. Can this be done safely using an implementation like what I see here: http://www.justsoftwaresolutions.co.uk/threading/implementing-a-thread-safe… ? Note 1: -= denotes a 1-to-N connect and =- a N-to-1 connect RR = Request reply relationship +--------------------------------------------------------------------+ | | v | Pool A RR Thread Set 1 Router X | PULL-PUSH --==> PULL-read-PUSH ==--> PULL-PUSH --==> PULL Thread Set 2 PUSH \ / +-compress-+ Pool B RR / \ PULL-PUSH --==> PULL PUSH ^ || | || +----------- PUSH-write-PULL <--==++ Pool C Questions: how do I have a separate thread poll on multiple shared message queues? Like, I have a thread pool that both receives requests for buffer handles and that receives old buffer handles to recycle.

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asio/ip/udp.hpp causes MSVC to use std::bind
by Chris Stankevitz 30 Jan '14

30 Jan '14

boost 1.55 VS2012 Update 4 === Can you tell me why the following code fails to compile? It smells as if udp.hpp is causing MSVC to "using namespace std". PS: It doesn't happen if I remove the asio include. PPS: It doesn't happen if g() takes int vs std::string. PPPS: It doesn't happen on GCC Thank you, Chris === #include <boost/bind.hpp> #include <boost/asio/ip/udp.hpp> #include <string> using boost::bind; void g(const std::string&) { } int main() { bind(g, _1); return 0; } === 1>------ Build started: Project: OverlayServer, Configuration: Debug Win32 ------ 1> main.cpp 1>main.cpp(13): error C2668: 'std::bind' : ambiguous call to overloaded function 1> c:\program files (x86)\microsoft visual studio 11.0\vc\include\functional(1387): could be 'std::_Bind<_Forced,_Ret,_Fun,_V0_t,_V1_t,_V2_t,_V3_t,_V4_t,_V5_t,<unnamed-symbol>> std::bind<void,const std::string&,boost::arg<I>&>(_Rx (__cdecl *)(const std::basic_string<_Elem,_Traits,_Alloc>),_Vx0_t)' [found using argument-dependent lookup] 1> with 1> [ 1> _Forced=true, 1> _Ret=void, 1> _Fun=void (__cdecl *const )(const std::string &), 1> _V0_t=boost::arg<1> &, 1> _V1_t=std::_Nil, 1> _V2_t=std::_Nil, 1> _V3_t=std::_Nil, 1> _V4_t=std::_Nil, 1> _V5_t=std::_Nil, 1> <unnamed-symbol>=std::_Nil, 1> I=1, 1> _Rx=void, 1> _Elem=char, 1> _Traits=std::char_traits<char>, 1> _Alloc=std::allocator<char>, 1> _Vx0_t=boost::arg<1> & 1> ] 1> c:\externalpackages\boost_1_55_0\boost\bind\bind_cc.hpp(26): or 'boost::_bi::bind_t<R,F,L> boost::bind<void,const std::string&,boost::arg<I>>(R (__cdecl *)(B1),A1)' 1> with 1> [ 1> R=void, 1> F=void (__cdecl *)(const std::string &), 1> L=boost::_bi::list1<boost::arg<1>>, 1> I=1, 1> B1=const std::string &, 1> A1=boost::arg<1> 1> ] 1> while trying to match the argument list '(overloaded-function, boost::arg<I>)' 1> with 1> [ 1> I=1 1> ] ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

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[accumulators] "count" NaN but otherwise ignore it?
by Rhys Ulerich 29 Jan '14

29 Jan '14

Is there a feature within accumulators to count NaNs on extraction but to otherwise ignore them? Maybe some sort of pass filter on incoming data? I've got a situation where I'd like to avoid NaNs clobbering otherwise useful information, but I still want to total count of data seen to include them. The context is a time integrator for a physics simulation. The integrator tracks the number of timesteps. When the physics kicks back a NaN (because something's amiss), I'd like to count the failed timestep but not have the NaN destroy the useful mean of timesteps taken thus far. Thanks, Rhys

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Avoid transitive link dependency
by Dario Ramos 29 Jan '14

29 Jan '14

I wrote a serial port static library using boost::asio. I'm trying to use this library from another project I'm building as a dll, but this second project fails to link: it wants to link with Boost's sytem library. I used PIMPL to remove all boost #includes from my class header, and also tried setting Visual Studio's Link Library Dependencies option set to Yes in my static library. Neither approach worked. I know I can solve this by adding the boost binary directory to the library directories for my dll project, but I'd like to avoid that. The way I see it, only my static library should have a Boost link dependency. I'm using Visual Studio 2012, targetting to Windows XP (v110_xp toolset), and Boost 1.53.0. I asked about this at Stack Overflow if anyone's interested: http://stackoverflow.com/questions/21435666/avoid-link-dependency-with-boost -- *Darío Eduardo Ramos* Meditech S.A. www.meditech.com.ar (+54) 01147603300, Interno 31 Av. Julio A. Roca 3456 Florida Oeste, Bs.As. Argentina

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[Container] any debug renderings for Visual Studio?
by John M. Dlugosz 29 Jan '14

29 Jan '14

When I try to inspect, say, a flat_vector (or anything built on top of it like a flat_map) I can't see the elements in the Watch display. Is there some way to teach VS about that? I seem to remember a long time ago having VS skip things like shared_ptr dereference when stepping through.

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boost condition_variable internals
by Kenneth Adam Miller 29 Jan '14

29 Jan '14

I need to know that boost does not use any kind of locking, mutex or semaphore mechanism within the boost::condition_variable class. I don't know where it is in source, or I would check to make certain. Can someone provide me a yes no verification?

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[offtopic] C++Now 2014 - hotel room available
by Hartmut Kaiser 29 Jan '14

29 Jan '14

I apologize for posting off-topic. Hey all, Unfortunately I will not be able to come to C++Now this year. However I already booked my hotel room at the Aspen Meadows (at the early bird rate!). If anybody is interested in using the hotel reservation, please get in contact with me offline. Thanks! Regards Hartmut --------------- http://boost-spirit.com http://stellar.cct.lsu.edu

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C++Now 2014 Student Volunteer Program Accepting Applications - Please help spread the word
by Bryce Adelstein-Lelbach 28 Jan '14

28 Jan '14

C++Now, presented by Boost in-cooperation with the ACM, is an international gathering of C++ programmers. In 2013, the conference launched a Student/Volunteer Program to enable young coders to attend the conference. This year, we are again are inviting students with an interest in C++ programming to attend the May 12-17, 2014 conference in Aspen, CO as Student/Volunteers. The program is an excellent way for students with any interest in C++ to learn about C++ and make lasting connections with the C++ community. "Attending has truly been one of the most inspirational moments of my life. I had the opportunity to learn, socialize and have a great time in general. I hope to attend this conference yearly now and make a lasting impact in the computer science community." - Grant Mercer, 2013 C++Now Student/Volunteer. "All of the attendees had knowledge to share. Although the talks can be seen online, nothing can compare to being surrounded by over a hundred C++ enthusiasts." - Alex Duchene, 2013 C++Now Student/Volunteer Student/Volunteers will receive free registration. A limited number of applicants will receive stipends for travel expenses. Volunteers will handle various tasks during the conference, such as assisting presenters, setting up presentation rooms, running A/V equipment and helping with the conference picnic. Students from all fields of study are welcome to apply. However, this conference covers advanced C++ topics, and applicants should have ample experience with the C++ programming language and be familiar with general computer science topics. Applications will be accepted until February 15th, 2014. Application decisions will be sent out by March 18th, 2014. You can learn more about the program and some of the students who have participated at http://cppnow.org/volunteer. -- Bryce Adelstein-Lelbach, Student/Volunteer Chair

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