August 2012 - Boost-users - lists.preview.boost.org

Boost 1.51.0 released!
by Marshall Clow 21 Aug '12

21 Aug '12

Release 1.51.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains 1 new library (Boost.Context, by Oliver Kowalke) and numerous enhancements and bug fixes for existing libraries. For details, including download links, see http://www.boost.org/users/news/version_1_51_0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.51.0/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Beman Dawes Daniel James Eric Niebler Marshall Clow Rene Rivera Vladimir Prus

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[unordered_map]: Unexpected exception on value insertion
by Johannes Brunen 21 Aug '12

21 Aug '12

Hello, My program is crashing (not handling an unexpected exception) on inserting a value into a unorderd map of type: unordered_map<osg::Pnt3f, std::size_t, Pnt3fHashT> with struct Pnt3fHashT : public std::unary_function<osg::Pnt3f, std::size_t> { std::size_t operator()(const osg::Pnt3f& pnt) const { std::size_t seed = 0; boost::hash_combine(seed, pnt[0]); boost::hash_combine(seed, pnt[1]); boost::hash_combine(seed, pnt[2]); return seed; } }; Pnt3f is a common 3D float point. The program is compiled with Microsoft Visual C++ 2008 9.0.30729.1SP 64Bit and Boost 1.48.0. The crash does only occur on 64Bit compilations. After inspection, I found the crash to be happening in the function inline std::size_t float_hash_impl2(T v) found in source hash_float_generic.hpp. Since the code looks fine for me I investigated the generated assembler code and found std::size_t seed = static_cast<std::size_t>(v); 000007FEE8A4D3C0 xor ecx,ecx 000007FEE8A4D3C2 movss xmm0,dword ptr [v] 000007FEE8A4D3CB comiss xmm0,dword ptr [__real@5f000000 (7FEE8FB7A34h)] 000007FEE8A4D3D2 jbe boost::hash_detail::float_hash_impl2<float>+0D2h (7FEE8A4D3F2h) 000007FEE8A4D3D4 subss xmm0,dword ptr [__real@5f000000 (7FEE8FB7A34h)] 000007FEE8A4D3DC comiss xmm0,dword ptr [__real@5f000000 (7FEE8FB7A34h)] 000007FEE8A4D3E3 jae boost::hash_detail::float_hash_impl2<float>+0D2h (7FEE8A4D3F2h) 000007FEE8A4D3E5 mov rax,8000000000000000h 000007FEE8A4D3EF add rcx,rax 000007FEE8A4D3F2 cvttss2si rax,xmm0 000007FEE8A4D3F7 add rax,rcx 000007FEE8A4D3FA mov qword ptr [seed],rax The crash happens at the 000007FEE8A4D3F2 cvttss2si rax,xmm0 instruction since the value in xmm0 is larger than the maximum signed 32bit integer. In this case depending on the settings an floating-point invalid exception is raised. It crashes since my code is not prepared for this exception. Now I have some questions: 1. Is it known that this mapping into the realm of 32Bit is happening for the above cast operation? 2. Is this a compiler bug? The generated assembler code does not allow 'safe' casting into 64bit integer? 3. Any advice how I should handle this situation? Best, Johannes ____________ Virus checked by G DATA AntiVirusKit Version: AVF 22.889 from 20.08.2012 Virus news: www.antiviruslab.com

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[boost] [type_erasure] Review report -- ACCEPTED
by Lorenzo Caminiti 21 Aug '12

21 Aug '12

Hello all, Steven Watanabe's library Boost.TypeErasure is ACCEPTED into Boost. SUMMARY The library was reviewed from July 18 to August 3, 2012. There were 11 votes to accept the library and 2 votes to accept the library under the condition of some modifications (at the end, these 2 votes were essentially considered as "no" because there was no agreement on implementing all the required modifications). It was noted how the library offers non-intrusive and powerful programming techniques that can be used in place of usual Object Oriented (pure) virtual function interfaces (and with support for some from of virtual "template" functions). The library can also be seen as a generalization of existing Boost libraries like Any, Function, and AnyIterator. The library is accepted "as is", however most reviewers suggested to: 1) Dramatically ease the learning curve of the documentation by providing a motivation section, step-by-step tutorial(s) to introduce the basic features of the library, advanced topics section(s) to introduced the additional features, an example section with non-trivial use cases for the library, and additional examples to the reference section. 2) Support down-casting. While these changes are not a condition for the library acceptance, it would be best if they were made part of the very first release of the library. A few reviewers found the name Type Erasure confusing, however others did not. Alternative name were: Staged Typing, Deferred Typing, Type Interface, Interface, Static Interface, Value Interface, Structural Typing, Duck Typing, and Run-Time Concepts. There was some discussion on the meaning of Type Erasure in Java and on its definition on wiki (these should probably be both referenced in the documentation). The current library name is considered acceptable and the final decision on the library name is left entirely up to Steven. DETAILS "Yes" reviews: [1] http://lists.boost.org/Archives/boost/2012/07/195288.php [2] http://lists.boost.org/Archives/boost/2012/07/195297.php [3] http://lists.boost.org/Archives/boost/2012/07/195299.php [4] http://lists.boost.org/Archives/boost/2012/07/195308.php [5] http://lists.boost.org/Archives/boost/2012/07/195323.php [6] http://www.mentby.com/hossein-haeri/boost-typeerasure-review-ends-today-jul… [7] http://lists.boost.org/Archives/boost/2012/07/195327.php [8] http://lists.boost.org/Archives/boost/2012/07/195329.php [9] http://lists.boost.org/Archives/boost/2012/07/195334.php [10] http://lists.boost.org/Archives/boost/2012/07/195364.php [11] http://lists.boost.org/Archives/boost/2012/08/195420.php "Conditional-yes" reviews (essentially considered as "no"): [12] http://lists.boost.org/Archives/boost/2012/08/195455.php [13] http://lists.boost.org/Archives/boost/2012/08/195561.php Notable comments and discussions (not reviews): (1) http://lists.boost.org/Archives/boost/2012/07/195162.php (2) http://lists.boost.org/Archives/boost/2012/07/195130.php (3) http://lists.boost.org/Archives/boost/2012/07/195149.php (4) http://lists.boost.org/Archives/boost/2012/07/195167.php (5) http://lists.boost.org/Archives/boost/2012/07/195199.php (6) http://lists.boost.org/Archives/boost/2012/07/195200.php (7) http://lists.boost.org/Archives/boost/2012/07/195232.php (8) http://lists.boost.org/Archives/boost/2012/07/195234.php (9) http://lists.boost.org/Archives/boost/2012/07/195408.php (10) http://permalink.gmane.org/gmane.comp.lib.boost.user/75081 (11) http://lists.boost.org/Archives/boost/2012/08/195590.php (12) http://lists.boost.org/Archives/boost/2012/08/195663.php (13) http://lists.boost.org/Archives/boost/2012/07/195342.php (14) http://lists.boost.org/Archives/boost/2012/08/195543.php Note that Steven might have already implemented some of the changes listed below. Features: * Support down-casting. See [1], [10], and (4). * Add macros for defining concepts. These macros could be added in later revisions (they just provide a different syntax, no additional functionality). ** From [10]: BOOST_CREATE_CONCEPT(container_concept, typename T, (void (push_back, T), void (size)) ) ** From Steven: BOOST_TYPE_ERASURE_MEMBERS((push_back)(size)...) template<class V, class T = _self> struct container_concept : mpl::vector< has_push_back<void(const V&), T>, has_size<std::size_t(), const T>, ...> {}; * Add empty() to check if any holds a value or not. See [3] and [11]. * Add a built-in concept for unary plus +x (just pick a name for it). See (11). Implementation: * Can assertion enforce that same bindings are required for the placeholders? See [13] and (3). * Add assertion to check that in functions with multiple arguments the underlining any types must match. See (7). * Add in-code comments to the implementation (at least to normalize.hpp). See [8] and [13]. * Can static assertions be used to improve error messages (see [8])? Concept mismatch spew errors with internal implementation details, see [10]. * Fix bugs: ** http://lists.boost.org/Archives/boost/2012/07/195367.php ** http://lists.boost.org/Archives/boost/2012/07/195396.php ** http://lists.boost.org/Archives/boost/2012/08/195662.php Documentation: * A few typos listed in [9]. * A draft on a proposed way to restructure the docs was offered in [8]. * Sean Parent's BoostCon 2012 "Value Semantics" could be used to write a motivation section. See [9]. * Offer a comparison with usual OO (pure) virtual function interfaces. See [1], [7], [8], and [9]. * Make sure all important elements document in the reference section are also documented in a tutorial section (e.g., how the any constructor binds placeholders, conversions, BOOST_TYPE_ERASURE_MEMBER, concept_of, etc). See (1), (4), (6), and [1]. * Clarify that references can be assigned but they cannot be rebound to a different object. See (2). * Clarify the rationale for using _a, _b, ... instead of _1, _2, ... as soon as _a, _b, ... are first used (most users miss the "named vs. positional parameter" rationale from the design decision section and _1, _2, ... are such common constructs that many users will naturally question the _a, _b, ... choice). See (5). * Add an example section with non-trivial use cases of the library. Consider to add the following examples: ** How to implement visitation, see (8). ** Model view controller, see [1]. ** Run-time expression system (adding Concept = void specialization), see [3]. ** Multi-function, see [4]. ** Printing, see (11) (note that Steven needed to answer too many questions for Paul to be able to program this, ideally the docs would have been clear enough for Paul to program this example without Steven's help). ** Reference related work Adobe::Poly, see (13). * Document all built-in concepts (possibly with a usage example for each) and indicate which ones can be specialized. See [5], and [9]. * Add an example at the bottom of each reference page. See [11]. * Document that any(any<Concpet2, T2>, binding<Concept>) allows to convert the vtable once and re-use it for all anys reducing run-time cost. See [12]. * Consider a number of docs improvements as suggested in [13]. * Document the undefined behaviour pointed out in (12). * Document limitations that some algorithms might encounter if they need to access references and provide rationale of why references cannot be handled differently (i.e., constructor flag and/or overhead of managing vtable in dispatcher layer). See [12], and (14). Many thanks to everyone that participated in the review!! I believe Boost users will find this library useful. The review manager, --Lorenzo On Sat, Aug 4, 2012 at 12:32 PM, Lorenzo Caminiti <lorcaminiti(a)gmail.com> wrote: > Hello all, > > The review of Boost.TypeErasure ended on Aug 3, 2012. Stay tuned for > my decision on the library. > > Thank you very much to Steven, everyone that submitted a review, and > everyone that participated in the discussions. > > The review manager, > --Lorenzo > > On Fri, Aug 3, 2012 at 11:00 AM, Lorenzo Caminiti <lorcaminiti(a)gmail.com> wrote: >> Hello all, >> >> *** The review of Boost.TypeErasure ends today Aug 3, 2012. If you are >> planning to submit a review, please do so by the end of today. *** >> >> Thank you to all that have participated to the review so far. >> >> The review manager, >> --Lorenzo >> >> On Jul 27, 2012 1:41 PM, "Lorenzo Caminiti" <lorcaminiti(a)gmail.com> wrote: >>> >>> Hello all, >>> >>> After consulting the review wizards and Steven, I am extending >>> Boost.TypeErasure review of one week, until August 3, 2012. >>> >>> Thank you to all that have submitted a review already and I am looking >>> forward to receiving additional submissions. >>> >>> The review manager, >>> --Lorenzo >>> >>> On Jul 27, 2012 3:22 AM, "Lorenzo Caminiti" <lorcaminiti(a)gmail.com> wrote: >>>> >>>> Hello all, >>>> >>>> On Mon, Jul 23, 2012 at 9:09 AM, Lorenzo Caminiti <lorcaminiti(a)gmail.com> >>>> wrote: >>>> > On Wed, Jul 18, 2012 at 1:13 AM, Lorenzo Caminiti >>>> > <lorcaminiti(a)gmail.com> wrote: >>>> >> *** The review of Steven Watanabe's proposed Boost.TypeErasure library >>>> >> begins on July 18, 2012 and ends on July 27, 2012. *** >>>> > >>>> > *** Boost.TypeErasure review ends in 5 days. Please submit your reviews >>>> > :D *** >>>> >>>> *** Boost.TypeErasure review ends today July 27, 2012. If you are >>>> planning to submit a review, please do so as soon as possible. *** >>>> >>>> Thank you to everyone who has commented on the library and submitted a >>>> review so far! >>>> >>>> The review manager, >>>> --Lorenzo >>>> P.S. I am considering extending the review until end of day Sunday >>>> July 29, 2012... I will keep you posted. >>>> >>>> > There have been interesting discussions on the library on the ML but I >>>> > have not received any official review yet :( Especially if you are a >>>> > user of Boost Any, Function, and Any Iterator, you definitely want to >>>> > take a look at Type Erasure as it generalizes solutions provided by >>>> > those other libraries. >>>> > >>>> > Thank you. >>>> > >>>> > The review manager. >>>> > --Lorenzo >>>> > >>>> >> THE LIBRARY >>>> >> >>>> >> C++ provides runtime polymorphism through virtual functions. They are >>>> >> a very useful feature, but they do have some limitations. >>>> >> * They are intrusive. In generic programming, we can design an >>>> >> interface which allows third-party types to be adapted to it. >>>> >> * They require dynamic memory management. Of course, most of the >>>> >> problems can be avoided by using an appropriate smart pointer type. >>>> >> Even so, it still acts like a pointer rather than a value. >>>> >> * Virtual functions' ability to apply multiple independent concepts to >>>> >> a single object is limited. >>>> >> The Boost.TypeErasure library solves these problems allowing us to >>>> >> mirror static generic programming at runtime. >>>> >> >>>> >> Library source: >>>> >> http://svn.boost.org/svn/boost/sandbox/type_erasure/ >>>> >> >>>> >> Pre-built documentation: >>>> >> >>>> >> http://steven_watanabe.users.sourceforge.net/type_erasure/libs/type_erasure/ >>>> >> >>>> >> You can also download archives with pre-built documentation from: >>>> >> http://sourceforge.net/projects/steven-watanabe.u/files/ >>>> >> >>>> >> YOUR REVIEW >>>> >> >>>> >> Please submit a review to the mailing-list by replying to this email >>>> >> ("[boost] [type_erasure] Review ..." should be in the subject). >>>> >> >>>> >> Please state clearly whether you think this library should be accepted >>>> >> as a Boost library. >>>> >> >>>> >> Other questions you may want to consider: >>>> >> 1. What is your evaluation of the design? >>>> >> 2. What is your evaluation of the implementation? >>>> >> 3. What is your evaluation of the documentation? >>>> >> 4. What is your evaluation of the potential usefulness of the library? >>>> >> 5. Did you try to use the library? With what compiler? Did you have >>>> >> any problems? >>>> >> 6. How much effort did you put into your evaluation? A glance? A >>>> >> quick reading? In-depth study? >>>> >> 7. Are you knowledgeable about the problem domain? >>>> >> >>>> >> Thanks in advance to all who participate in the review discussion -- >>>> >> I'm looking forward to it!

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MSVS 2012 support
by Lemay.Steve 20 Aug '12

20 Aug '12

Will boost 1.51.0 include bjam (b2) support for using the MS VS 2012 build tools? The final MS VS2012 release to manufacturing was posted 8/15/2012 via MSDN. SGL

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[MPI]: Linking with MPICH2 under Cygwin leads to Runtime Error
by Murphy, John T. 20 Aug '12

20 Aug '12

Hello all, Problem: Boost.MPI code that compiles, links, and runs successfully on other platforms fails under Cygwin + MPICH2, giving the following error: "Attempting to use an MPI routine before initializing MPICH" The error seems related to calls to non-Boost MPI functions; it can occur when the Boost.MPI library is linked even though no functions in the boost::mph namespace are used. Altering the order in which libraries are given to the gcc linker can resolve the issue in simple cases (not shown here), but does not for our full code. Platform: Windows Vista, Cygwin newly installed with gcc4, openssh, curl and z libraries, MPICH2 built from source, Boost 1.48 and Boost 1.49 tested with same results (the current release of our code is incompatible with Boost 1.50 due to changes in the Boost.Filesystem library). Details: Initial test code (test.cpp): =================================== #include <iostream> #include <mpi.h> int main(int argc, char** argv){ MPI_Init(&argc, &argv); int rank; MPI_Comm_rank(MPI_COMM_WORLD, &rank); std::cout << " RANK " << rank << " RUNNING " << std::endl; if(rank == 0){ MPI_Status status; int mode = MPI_MODE_CREATE | MPI_MODE_WRONLY | MPI_MODE_APPEND; MPI_File out; std::string fileName("LOG.txt"); MPI_File_open(MPI_COMM_SELF, (char*)fileName.c_str(), mode, MPI_INFO_NULL, &out); MPI_File_close(&out); } MPI_Finalize(); std::cout << " RANK " << rank << " ENDING " << std::endl; return 0; } ====================================== Compilation, linking, invocation and output without using Boost.MPI: ======================================== John@Vista2 ~/TEST $ mpicxx -c -o test.o test.cpp John@Vista2 ~/TEST $ mpicxx -o test test.o John@Vista2 ~/TEST $ mpirun -n 2 ./test.exe RANK 0 RUNNING RANK 1 RUNNING RANK 0 ENDING RANK 1 ENDING John@Vista2 ~/TEST $ mpicxx -show c++ -I/home/John/MPICH/include -L/home/John/MPICH/lib -lmpichcxx -lpmpich -lmpich -lopa -lmpl -lpthread ========================================= Same code, but add an unnecessary link to Boost.MPI: ========================================= John@Vista2 ~/TEST $ mpicxx -L/home/John/boost_1_48_0/stage/lib -o test test.o -lboost_mpi-mt John@Vista2 ~/TEST $ mpirun -n 2 ./test.exe RANK 0 RUNNING RANK 1 RUNNING Attempting to use an MPI routine before initializing MPICH ========================================= (Note: the LOG.txt file is not created.) Code using Boost::MPI functions expclitly (test_boost.cpp): ============================================= #include <boost/mpi.hpp> #include <boost/mpi/environment.hpp> #include <boost/mpi/communicator.hpp> #include <iostream> namespace mpi = boost::mpi; int main(int argc, char** argv){ mpi::environment env(argc, argv); mpi::communicator world; int rank = world.rank(); std::cout << " RANK " << rank << " RUNNING " << std::endl; if(rank == 0){ MPI_Status status; int mode = MPI_MODE_CREATE | MPI_MODE_WRONLY | MPI_MODE_APPEND; MPI_File out; std::string fileName("LOG.txt"); MPI_File_open(MPI_COMM_SELF, (char*)fileName.c_str(), mode, MPI_INFO_NULL, &out); MPI_File_close(&out); } std::cout << " RANK " << rank << " ENDING " << std::endl; return 0; } ========================================== Compilation, linking, and running: ========================================== John@Vista2 ~/TEST $ mpicxx -c -I/home/John/boost_1_48_0/ -o test_boost.o test_boost.cpp John@Vista2 ~/TEST $ mpicxx -L/home/John/boost_1_48_0/stage/lib -o test_boost test_boost.o -lboost_mpi-mt John@Vista2 ~/TEST $ mpirun -n 2 ./test_boost.exe RANK 0 RUNNING RANK 1 RUNNING RANK 1 ENDING Attempting to use an MPI routine before initializing MPICH =========================================== The other system I have easy access to, and on which this code runs correctly, is a Mac/Unix-like using OpenMPI, but the need is for this code (and, more importantly, for our larger project, where the error was first observed) to run under Cygwin. I do not know how to diagnose whether this is a Boost.MPI issue, an MPICH2 issue, or something related to how the two libraries work together. Any help appreciated- thanks, John -- John T. Murphy Computational Postdoctoral Fellow Decision and Information Sciences and Argonne Leadership Computing Facility Argonne National Laboratory jtmurphy(a)anl.gov

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installed version / build option
by Kraus Philipp 20 Aug '12

20 Aug '12

Hello, can I read the build / version of the installed Boost from a file? I would like to grep the version and multithread / singlethread install option from the Boost include directory. Thanks Phil

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Thread overhead
by Alireza Haghdoost 20 Aug '12

20 Aug '12

Hi Is there anyway to reduce overhead of threadFoo() call in this simple program ? class baseClass { public: void foo(){ boost::posix_time::milliseconds delay(143); boost::this_thread::sleep(delay); } void threadFoo(){ threadObjOne = boost::thread(&baseClass::foo, this); threadObjTwo = boost::thread(&baseClass::foo, this); threadObjOne.join(); threadObjTwo.join(); } private: boost::thread threadObjOne; boost::thread threadObjTwo; }; int main(){ std::cout<< "main startup"<<std::endl; baseClass baseObj; tick_t startTime,endTime; rdtscll(startTime); baseObj.foo(); rdtscll(endTime); std::cout<<"native foo() call takes "<< endTime-startTime <<" clock cycles"<<std::endl; rdtscll(startTime); baseObj.threadFoo(); rdtscll(endTime); std::cout<<"Thread foo() call takes "<< endTime-startTime <<" clock cycles"<<std::endl; } The output is : main startup native foo() call takes 368222398 clock cycles Thread foo() call takes 372600905 clock cycles

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Re: [Boost-users] boost::math::standard_deviation how to use ?
by Edouard Tallent 19 Aug '12

19 Aug '12

My 2-cent One can easily compute the standard deviation of data contained in a std::vector as shown here: http://stackoverflow.com/questions/7616511/calculate-mean-and-standard-devi… Another option is resorting on boost, and any boost container as here: http://www.boost.org/doc/libs/1_41_0/libs/math/doc/sf_and_dist/html/math_to… I mean I am not sure ** in this case *** trying to mix standard vector and boost is the best solution. Best Edouard https://quantcorner.wordpress.com/ ========= Message: 4 Date: Fri, 17 Aug 2012 13:15:50 -0700 (PDT) From: leeto <denisigoshev(a)gmail.com> To: boost-users(a)lists.boost.org Subject: [Boost-users] boost::math::standard_deviation how to use ? Message-ID: <1345234550791-4634435.post(a)n4.nabble.com> Content-Type: text/plain; charset=us-ascii How to compute standard_deviation using boost I want that interface will be like in excel i mean you mark some data and that all ) How do the same in c++ boost using data from a standard container like vector for example... Many thanks in advance #include <boost/math/distributions.hpp> // For non-member functions of distributions #include <vector> #include <numeric> using namespace std; int main () { std::vector<double> v; for (unsigned int i = 0; i < 7; i++) { v.push_back(std::rand()%7); } std::vector<double>::iterator i = v.begin(); for (i ; i != v.end(); ++i) { std::cout << (*i) << ", "; } cout << std::accumulate(v.begin(), v.end(),0) << endl; //boost::math::normal_distribution cout << "\n\n\n" ; return 0;

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Boost Style Guide ?
by Cowing-Zitron, Christopher 18 Aug '12

18 Aug '12

Hello, I am a relative newbie to C++, in that I have been using it for about a year, and am comfortable with using it, capable of reading complex code, able to create my own libraries, and familiar with (I think) all of the fundamental constructs. But what I have not yet cultivated is my own style, in terms of formatting, structure of packages (i.e. separation of declaration and definition, inclusion hierarchies), idioms, naming conventions, etc. Given that Boost is so well written, so highly respected and relied upon, and second only to the actual standard in terms of authority, I thought I might try emulating Boost style in my coding. To that end, is there an (un)official Boost Style Guide? Or can you recommend another library/set-of-libraries worth trying to emulate that does provide a style guide? Given that the software I write is all scientific/numerical libraries for machine learning and bioinformatics, should I even be looking to a utility/metaprogramming library like Boost for style inspiration? If not, can anyone recommend some C++ numerical libraries which display especially solid coding style and structure, even if they are not necessarily the optimal libraries in terms of their numerical properties? Thanks everybody, -- Chris

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undefined reference to boost::filesystem
by Thibaut Lepage 18 Aug '12

18 Aug '12

Hello, I can't link against the filesystem library. When I try to compile a program using boost::filesystem (like the simple one attached to this email), I get "undefined reference" errors from the linker: dourak@Vvardenfell:~$ g++ -o dummy dummy.cpp -lboost_filesystem -lboost_system /tmp/ccMpl6cj.o: In function `boost::filesystem::exists(boost::filesystem::path const&)': dummy.cpp:(.text._ZN5boost10filesystem6existsERKNS0_4pathE[boost::filesystem::exists(boost::filesystem::path const&)]+0x19): undefined reference to `boost::filesystem::detail::status(boost::filesystem::path const&, boost::system::error_code*)' /tmp/ccMpl6cj.o: In function `boost::filesystem::path::path<char*>(char* const&, boost::enable_if<boost::filesystem::path_traits::is_pathable<boost::decay<char*>::type>, void>::type*)': dummy.cpp:(.text._ZN5boost10filesystem4pathC2IPcEERKT_PNS_9enable_ifINS0_11path_traits11is_pathableINS_5decayIS4_E4typeEEEvE4typeE[_ZN5boost10filesystem4pathC5IPcEERKT_PNS_9enable_ifINS0_11path_traits11is_pathableINS_5decayIS4_E4typeEEEvE4typeE]+0x22): undefined reference to `boost::filesystem::path::codecvt()' collect2: ld a retourné 1 code d'état d'exécution I carefully sorted the libraries in the command line, since gcc has trouble with library dependencies, sometimes, but it still doesn't work. I use gcc 4.6.3 on Ubuntu 12.04 64bits. The problem occurs either with boost 1.46.1 (taken from the repositories) or with 1.50.0 (installed with bjam). Any hint ? Thibaut Lepage

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