October 2011 - Boost-users - lists.preview.boost.org

dubious range mismatch prerequisite
by Krzysztof Żelechowski 17 Nov '11

17 Nov '11

The documentation for mismatch, as applied to ranges, says that rng2 must be at least as long as rng1. Why is this precondition necessary? The precondition is impossible to evaluate for bare input iterators without destroying the iterators, whereupon it is impossible to call mismatch any more. IMHO, it would be perfectly reasonable to stop at the end of rng2 if rng2 is shorter. <URL: http://www.boost.org/doc/libs/1_47_0/libs/range/ doc/html/range/reference/algorithms/non_mutating/mismatch.html >

2 1

[graph] adjacency_list constructor fails, wrong usage?
by Christoph 15 Nov '11

15 Nov '11

Hi, I originally wanted to construct an undirected graph from a directed graph and vice versa. For this purpose i tried to use template <class EdgeIterator> adjacency_list(EdgeIterator first, EdgeIterator last, vertices_size_type n, edges_size_type m = 0, const GraphProperty& p = GraphProperty()) as shown in http://www.boost.org/doc/libs/1_47_0/libs/graph/doc/adjacency_list.html but i do not even manage to construct a graph from the same type with this constructor. What am i missing? Please have a look at the example below. If you uncomment the last two lines, the code will not compile. // begin code #include <iostream> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/graph_utility.hpp> int main(int argc, char** argv) { typedef boost::adjacency_list < boost::listS, boost::vecS, boost::directedS> Dgraph; typedef boost::adjacency_list < boost::listS, boost::vecS, boost::undirectedS> Graph; Dgraph g(5); add_edge (0,1,g);add_edge (2,3,g);add_edge (4,5,g); print_graph (g, boost::get(boost::vertex_index, g)); boost::graph_traits<Dgraph>::edge_iterator i1 = (edges(g)).first; boost::graph_traits<Dgraph>::edge_iterator i2 = (edges(g)).second; // Dgraph g2 = Dgraph (i1, i2, num_vertices (g), num_edges (g)); // print_graph (g2, boost::get(boost::vertex_index, g2)); return 0; } // end code best regards Christoph

3 3

[ASIO] Flush output on socket
by Claude 12 Nov '11

12 Nov '11

Hi! I use this code for send a std::string with a socket: I have a doubt: this function automatically flush its output? -- View this message in context: http://boost.2283326.n4.nabble.com/ASIO-Flush-output-on-socket-tp3951921p39… Sent from the Boost - Users mailing list archive at Nabble.com.

2 6

[mpi/serialization] Potential bug or just library misunderstanding?
by Tim Jacobs 10 Nov '11

10 Nov '11

I'm not sure why the following test-class produces this error: "MPI_Recv: MPI_ERR_TRUNCATE: message truncated" If the std::map has only a single element (ie I remove one of the test[].push_back() lines) the error does not occur. Can someone verify that this is indeed a bug and not just novice misuse of the library? Thanks, Tim #include <boost/mpi.hpp> #include <boost/serialization/string.hpp> #include <boost/serialization/vector.hpp> #include <boost/serialization/map.hpp> int main( int argc, char * argv [] ) { boost::mpi::environment env(argc, argv); boost::mpi::communicator world; if(world.rank()==0){ std::map<int, std::vector<std::string> > test; test[1].push_back("FOO"); test[50].push_back("BAR"); world.send(1, 1, boost::mpi::skeleton(test)); world.send(1, 1, boost::mpi::get_content(test)); std::cout << "sent" << std::endl; } else{ std::map<int, std::vector<std::string> > test; world.recv(0,1,boost::mpi::skeleton(test)); world.recv(0,1,boost::mpi::get_content(test)); } }

4 6

[C++ Now! 2012] Call for Submissions
by Hartmut Kaiser 10 Nov '11

10 Nov '11

INAUGURAL C++ NOW! CONFERENCE 2012 Aspen CO, USA, May 14-18, 2012, www.cppnow.org CALL FOR SUBMISSIONS We invite you to submit session proposals to the Inaugural C++ Now! Conference: C++Now! 2012 (Aspen CO, USA, May 14 - 18, 2012). Based on the successful traditions of 5 years of BoostCon, which was the main face-to-face event for all things C++ and Boost (www.boost.org), C++Now! 2012 will present leading speakers from the whole C++ community. The conference name is changing to C++ Now! to reflect the current value of the language, the focus on its new state (from the new Standard), and the need to continually look to the future so the language remains useful to the C++ community. The focus of this conference will be the new C++11 language Standard and as usual Boost: what's new in C++, its Standard library, and in the Boost libraries, how to write and maintain them, how to evangelize or to deploy Boost within your organization. The new C++ Standard, but also the infrastructure and process of Boost, its vision and mission - no matter what you are interested in, it all comes together in the C++Now! sessions. Meet the colleagues, and feel the inspiration to support your work with C++ and Boost for the next year. The C++ Now! Conference is dedicated to discussion and education about C++, an open and free language and standard. Our Conference will focus on discussion and education about open source software usage and developments in the C++ developer and user community. To reflect the breadth of the C++ and Boost communities, the conference includes sessions aimed at three constituencies: C++ and Boost end-users, hard-core Boost library and tool developers, and researchers pushing the boundaries of computation. The program fosters interaction and engagement within and across those groups, with an emphasis on hands-on, participatory sessions. As a multi-paradigm language, C++ is a melting pot where the most compelling ideas from other programming communities are blended in powerful ways. Historically, some of the most popular sessions at C++Now! have highlighted these concepts, from DSLs to functional programming to transactional memory and more. Bring your C#, Python, Ruby or Haskell influences to bear in an environment that will broaden their exposure. IMPORTANT DATES New proposal submissions due: January 10th, 2012. Proposals decisions sent (tentative program available): February 17th, 2012. Fully scheduled program available: February 25th, 2012. Session materials due: April 15th, 2012. BEST PRESENTATION AWARDS We know how much effort it takes to prepare talks for our conference. For this reason we will award the best presentations in the following categories: Best Presentation, Best Short Presentation, Best Tutorial, and Best Workshop. The awards will be given based on the audience's voting. Each award will include the author's name listed on the cover of the C++Now! website for that year and a plaque containing all the C++Now! conference information. SESSION TOPICS Topics of interest include, but are not restricted to, the following: * C++11 and how it changes life for users and library writers * General tutorial sessions on C++11, the C++11 Standardslibrary, and one or more Boost libraries * In-depth sessions on using specific Boost libraries * Case studies on using Boost * Experts panels * Advanced sessions on implementation techniques used within Boost libraries * Development workshops to extend or enhance existing Boost libraries * Workshops on design process * Infrastructure workshops such as Build tools, Website, Testing * Concepts and Generic Programming * Hardware and infrastructure presentations focused on how libraries can make better use of the technology * Software development tools and their application to C++ and or Boost * Other topics likely to be of great interest to Boost users and developers Interactive and collaborative sessions are encouraged, as this is the style of learning and participation that has proven most successful at such events. Sessions can be tutorial based, with an emphasis on interaction and participant involvement, or workshop based, whether hands-on programming or paper-based, discussion-driven collaborative work. SESSION FORMATS Presentations Presentations focus on a practitioner's ideas and experience with anything relevant to C++11, Boost and users. Panels Panels feature three or four people presenting their ideas and experiences relating to C++11 and Boost's relevant, controversial, emerging, or unresolved issues. Panels may be conducted in several ways, such as comparative, analytic, or historic. Tutorials Tutorials are sessions at which instructors teach conference participants specific skills relevant to C++11 and Boost. Workshops Workshops provide an active arena for advancements in Boost-relevant topics. Workshops provide the opportunity for experienced practitioners to develop new ideas about a topic of common interest and experience. Author's Corner These were introduced at BoostCon 2008, and were a great Presentations success They are short (30 minute) sessions, focusing on tips on usage and design. In addition, we're looking to uncover the hidden design gems in Boost libraries. Tool Vendors We actively encourage tool vendors and ISP's to submit Presentations proposals for a special Tool Vendors Session Track aimed at products related to Boost and C++ (compilers, libraries, tools, etc.). Other formats may also be of interest. Don't hold back a proposal just because it doesn't fit into a pigeonhole. SUBMITTING A PROPOSAL Standard Sessions are 60 minutes. You may submit a proposal for fractions or multiples of 90-minutes. Fractional proposals will be grouped into 60 minute sessions covering related topics. Longer sessions, such as tutorials and classes, will be assigned 90 minute, three hour (i.e. half day), or six hour (i.e. full day) time slots. Please include: * The working title. * Type of session: presentation, panel, tutorial, workshop, authors corner, vendor track, other. * A paragraph or two describing the topic covered, suitable for the conference web site. * Proposed length: 10-20 minute short talks, 45 minutes, 90 minutes, half day, full day. * Alternate lengths, if you are willing to make adjustments: 10- 20 minute short-talks, 45 minutes, 90 minutes, half-day, full day. * Audience: users, developers, both. * Level: basic, intermediate, advanced. * A biography, suitable for the conference web site. * Your contact information (will not be made public). SUBMISSION DETAILS All submissions should be made through the EasyChair conference management system: http://www.easychair.org/conferences/?conf=cppnow2012. If you have not already registered at EasyChair, you will need to do so in order to submit your proposal. All submissions will go through a peer review process. Authors are invited (but are not required) to submit PDF versions of full papers of up to 10 pages in ACM conference proceedings format (see http://www.acm.org/sigs/publications/proceedings-templates). The full papers are not required unless you want them published in the proceedings. All accepted proposals will be made available in the Association for Computing Machinery (ACM) Digital Library (approval pending). Best papers, after further reviews, will be considered to be book chapters or journal articles in a renowned journal. The session materials go on the C++Now! website and will be available to attendees. For general information on the C++Now! 2012 paper submission or the scope of technical papers solicited, please refer to the conference website at www.cppnow.org. For any other questions about the submission process or paper format, please contact the Program Committee at cppnow2012(a)easychair.com. If you have any technical problems with EasyChair, please contact EasyChair for help. Note: Presenters must agree to grant a non-exclusive perpetual license to publish submitted materials, either electronically or in print, in any media related to C++ Now!. Hartmut Kaiser, email: hartmut.kaiser(a)gmail.com (Program Committee Chair) Dave Abrahams, email: dave(a)boostpro.com (Conference Chair) On behalf of the conference organizers

3 5

[Move] unique_ptr
by Szymon Gatner 09 Nov '11

09 Nov '11

Hi, with now accepted Move library, is implementation of unique_ptr<> planned for boost? I used to use Howard Hinnant's implementation so far but got compilation problems as soon as I added Move library to my toolbox. Also, Hinnant's page says: "The following is a dated C++03 emulation of unique_ptr. You may find a better unique_ptr emulation at boost." Does he mean the one in Boost.Interprocess? Regards, Simon

3 10

multi-array and pdes
by petros 07 Nov '11

07 Nov '11

Hi, These can very well be very naive questions, since I am relatively new to this - apologies..: I am trying to write a pde solver for a 3D problem. Multi-array seems like a very natural choice for a data structure to store the functtion values. The method I am trying to use is operrator splitting. This amounts to solving a tridiagonal system for each dimension in sequence. Suppose then that I have a MA( M, N, L ): It is highly desirable to maintain this xyz (let's call it) "logical" system of reference since incorporation of boundary conditions and stencil calculations would be conceptually straightforward -otherwise very complicated. The idea being that, I would then have the tridiagonal opertator ( and rhs) in the "rotated" system and all other calculations in the "logical" one. Therefore, I need some fascility to rotate my MA, from the xyz to yzx etc (cyclically). Is there functionality ( as a view to the data ) that would allow me to do this off-the-shelve? Also, a couple of other points: -If I wanted to use views to subgrids, in parallelized calculations, are there memory allocations that happen under the hood for which I should worry (for performance)? -Is a one dimensional MA usable? -Are there adapters between 2D MAs and uBlas matrices? Thank you very much for your help in advance! P-

4 21

transfer_at_least_t
by Carla Strembicke 01 Nov '11

01 Nov '11

Hi, I have an object of transfer_at_least_t. I would like to find out what the minimum value is due to the fact that my app that set it is requiring so many bytes of unencrypted data, and the transfer is including the encryption. Is there any interface that can get this value or do I have to store it before I create the object transfer_at_least_t? Carla Strembicke Software Developer [cid:image015772.JPG@7ddd0ff8.4ca8ab2e] SUBNET Solutions Inc. www.SUBNET.com<http://www.SUBNET.com/> Making Substations More Intelligent T: 403.270.8885 F: 403.270.9631 #100, 4639 Manhattan Road SE, Calgary, Alberta, Canada; T2G 4B3 CONFIDENTIAL INFORMATION NOTICE: The information contained in this e-mail is privileged, confidential and intended solely for the use of the addressee named above. If the reader of this e-mail is not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this e-mail is strictly prohibited. If you received this in error, please contact the sender and destroy all copies of this e-mail. Thank you.

2 1

serialization of a ptr
by Jonathan Bishop 01 Nov '11

01 Nov '11

How do I prevent boost::serialize from treating a pointer as an object and serializing the object. I have written the specialization of save/load for the object pointer. I get the following errors when I attempt to compile the program below... boost/serialization/access.hpp: In static member function 'static void boost::serialization::access::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::binary_oarchive, T = X]': boost/serialization/serialization.hpp:81: instantiated from 'void boost::serialization::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::binary_oarchive, T = X]' boost/serialization/serialization.hpp:140: instantiated from 'void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::binary_oarchive, T = X]' boost/archive/detail/oserializer.hpp:151: instantiated from 'void boost::archive::detail::oserializer<Archive, T>::save_object_data(boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::binary_oarchive, T = X]' s3.cpp:53: instantiated from here boost/serialization/access.hpp:109: error: 'class X' has no member named 'serialize' ============================================================================================== #include <fstream> #include <sstream> #include <cstddef> #include <boost/archive/binary_iarchive.hpp> #include <boost/archive/binary_oarchive.hpp> #include "boost/serialization/split_free.hpp" using namespace std; class X { X(const X& other); X& operator=(const X& other); public : static X* get(int id); X() : id(0) {} int id; }; // Non-intrusive serialization (pretend I am not able to modify class X) // I was hoping serialization would use this specialization // archive X by id template<class Archive> void save(Archive& ar, X*& x, unsigned int version) { int id = x->id; ar & id; } // load X by lookup template<class Archive, class T> void load(Archive& ar, X*& x, unsigned int version) { int id; ar & id; x = X::get(id); } template<class Archive, class T> inline void serialize(Archive& ar, X*& t, const unsigned int version) { split_free(ar, t, version); } int main() { X x; std::ofstream ofs("junk"); boost::archive::binary_oarchive oa(ofs); oa & x; ofs.close(); return 0; }

3 3

[test] boost.test bug report email address?
by legalize+jeeves＠mail.xmission.com 01 Nov '11

01 Nov '11

[Please do not mail me a copy of your followup] The docs say I can report a bug to the email address <boost-test =at= emailaccount =dot= com> but this is undeliverable for 7 days. -- "The Direct3D Graphics Pipeline" -- DirectX 9 version available for download <http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/> Legalize Adulthood! <http://legalizeadulthood.wordpress.com>

2 1