November 2017 - Boost-users

function template argument deduction with std::tuple
by Ireneusz Szcześniak 23 Nov '17

23 Nov '17

Hi, I have a problem related to function template argument deduction with std::tuple (with boost::tuple too). I attach a file with the complete source you can compile. Below I describe the code. I have a template function declaration: > template <typename T> > auto > get_cost(const T &); Then I define my template types: > template <typename Graph> > using Vertex = typename Graph::vertex_descriptor; > > template <typename Graph> > using Label = std::tuple<Vertex<Graph>>; I define the specialization of the get_cost function for the Label type: > template <typename Graph> > auto > get_cost(const Label<Graph> &l) > { > return std::get<0>(l); > } I can define alright a variable of type Label: > struct graph > { > using vertex_descriptor = unsigned; > }; > > Label<graph> l; But I cannot use the templated function: > get_cost(l); I get this error: > error: use of 'auto get_cost(const T&) [with T = > std::tuple<unsigned int>]' before deduction of 'auto' I got this error with GCC HEAD 8.0.0 20171113 and Clang HEAD 6.0.0 (I used wandbox.org) Some other type definitions and their specializations of the get_cost function compile. For a struct derived from the std::tuple: > template <typename Graph> > struct Label1: std::tuple<Vertex<Graph>> > { > }; > > template <typename Graph> > auto > get_cost(const Label1<Graph> &l) > { > return std::get<0>(l); > } For a member of type std::tuple: > template <typename Graph> > struct Label2 > { > std::tuple<Vertex<Graph>> t; > }; > > template <typename Graph> > auto > get_cost(const Label2<Graph> &l) > { > return std::get<0>(l.t); > } For a member of type Vertex<Graph>: > template <typename Graph> > struct Label3 > { > Vertex<Graph> m_v; > }; > > template <typename Graph> > auto > get_cost(const Label3<Graph> &l) > { > return l.m_v; > } I would like to use the Label type, i.e., because it has the constructor and operators already defined, which I need. I would appreciate it if someone could explain what is going wrong here. Best, Irek

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Building b2 --prefix include directory not quite
by Michael Powell 22 Nov '17

22 Nov '17

Hello, So the B2 help indicates that the include directory should be whatever "<prefix>/include" is. So, I'm setting my prefix accordingly, something like, "/path/to/installed/boost-1.65.1", however, the include directory ends up being something a little more like this: "/path/to/installed/boost-1.65.1/include/boost-1_65_1". This looks like a bug to me. Can I set the --includedir myself and correct this during my build? Thank you... Cheers, Michael Powell

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[Interprocess] Waiting thread termination causes deadlock
by Markus Bonk 22 Nov '17

22 Nov '17

Hi, I am having issues with boost::interprocess::ipcdetail::spin_condition::do_wait_timed deadlocking. The issue occurs when a thread that is waiting due to a call to interprocess_condition_any::wait() terminates unexpectedly and interprocess_condition_any::notify_all() is called (from any process). The cause of the deadlock is not that the terminating thread held a lock – it doesn’t because it is waiting, but that spin_condition::m_num_waiters is never decremented to zero because one of the threads is no longer waiting and so the enter mutex is not freed. I have tried BOOST_INTERPROCESS_ENABLE_TIMEOUT_WHEN_LOCKING, however as far as I can see this only tells me that the deadlock is there. Are there any suggestions how I can recover from spin_condition not freeing the enter mutex? Or perhaps some way of avoiding the issue? Markus ________________________________ Markus Bonk Senior Software Engineer [cid:image19ab5c.GIF@24a568cc.448b8dc0] 3Dconnexion GmbH Clarita-Bernhard-Str. 18 81249 München Germany Tel: +49 (89) 897 45 42 - 70 Fax: +49 (89) 897 45 42 - 50 markus_bonk(a)3dconnexion.com<mailto:markus_bonk@3dconnexion.com> www.3dconnexion.com<http://www.3dconnexion.com> Geschäftsführer: Antonio Pascucci Sitz der Gesellschaft: München Registergericht: München HRB 99232

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Adding Lzma support to b2 invocation
by Michael Powell 22 Nov '17

22 Nov '17

Hello, So I've got LZMA downloading, have the include in hand, as well as what I presume are either object files and/or a DLL. Just need to know how to integrate that with my B2 invocation. Something like: -sLZMA_INCLUDE="/path/to/lzma/include" ? And then, how to include the object file with the linkage, or the DLL(s). And necessarily in which architecture/address-model. Otherwise, I am getting close to building. Around the corner from that is Locale support from ICU (?), which I've got downloading as well ATM. Cheers, Michael Powell

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Re: [Boost-users] Building boost b2 lzma options
by Michael Powell 21 Nov '17

21 Nov '17

Next errors seem to be lzma related. Is this along the same lines as with Zlib and bzip2? To avoid confusion, this is 1.65.1, as well; not the announced 1.66. Thanks! On Mon, Nov 20, 2017 at 1:41 PM, Nelson, Erik - 2 via Boost-users <boost-users(a)lists.boost.org> wrote: > Michael Powell Sent: Monday, November 20, 2017 1:24 PM >> >> I am building Boost and making progress. Thus far wondering what >> >> options to provide my B2. I added the zlib include path to the >> >> include="...;/path/to/zlib;...", and now seems to be wanting the LIB >> >> path? > > I use > > "-sBZIP2_SOURCE=/path/to/bzip2/src" "-sZLIB_SOURCE=/path/to/zlib/src" > > And it adds the source to the build. > > ---------------------------------------------------------------------- > This message, and any attachments, is for the intended recipient(s) only, may contain information that is privileged, confidential and/or proprietary and subject to important terms and conditions available at http://www.bankofamerica.com/emaildisclaimer. If you are not the intended recipient, please delete this message. > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > https://lists.boost.org/mailman/listinfo.cgi/boost-users

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Building boost b2 zlib options
by Michael Powell 20 Nov '17

20 Nov '17

Hello, I am building Boost and making progress. Thus far wondering what options to provide my B2. I added the zlib include path to the include="...;/path/to/zlib;...", and now seems to be wanting the LIB path? LINK : fatal error LNK1181: cannot open input file 'z.lib' LINK : fatal error LNK1181: cannot open input file 'zlib.lib' LINK : fatal error LNK1181: cannot open input file 'zll.lib' LINK : fatal error LNK1181: cannot open input file 'zdll.lib' Which option is that for B2? After that, it is on to finding bzip? fatal error C1083: Cannot open include file: 'bzlib.h': No such file or directory Is there a source download similar to that of zlib? I think I'm pretty close but for a handful of obscurish third party dependencies. Thanks! Cheers, Michael Powell

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Could guys help on OpenMP odeint 'for' statement error
by Renfan Luo 20 Nov '17

20 Nov '17

Hi All I have just started an OpenMP application example in VS2017 platform (/* Boost libs/numeric/odeint/examples/openmp/lorenz_ensemble_simple.cpp). When switch on Properties->C/C++->Language->Open MP Support-> Yes (/openmp), it has a build error Severity Code Description Project File Line Suppression State Error C3016 'i': index variable in OpenMP 'for' statement must have signed integral type OpenMP-test1 c:\users\renfanluo\source\repos\openmp-test1\openmp-test1\openmptest1.cpp 35 If When switch off Properties->C/C++->Language->Open MP Support-> Yes (/openmp) to No (/openmp), then the error goes off. However, "No" means OpenMP is switched off, which is not what I want. It is understood that in the for statement, the variables can be assigned with data type before, the errors associated with these user defined for statement will go off but the similar error shown below remain the same for boost header files. Severity Code Description Project File Line Suppression State Error C3016 'i': index variable in OpenMP 'for' statement must have signed integral type Test-OpenMP2 C:\boost_1_65_1\boost\numeric\odeint\external\openmp\openmp_range_algebra.hpp 72 Could you guys have any ideas of how to fix this problem? Best regards Renfan

1 0

[python::numpy] Access Violation when initializing numpy
by Christian Henning 18 Nov '17

18 Nov '17

Hi all, On Windows 10 with Visual Studio 2017 I', trying to run the following code in x64 debug configuration: #include <iostream> #include <boost/python.hpp> #include <boost/python/numpy.hpp> namespace p = boost::python; namespace np = boost::python::numpy; int main() { Py_Initialize(); np::initialize(); p::tuple shape = p::make_tuple(3, 3); np::dtype dtype = np::dtype::get_builtin<float>(); np::ndarray a = np::zeros(shape, dtype); return 0; } In the line np::initialize(); I'm getting a Exception thrown at 0x0000000066E43B15 (python36.dll) in test.exe: 0xC0000005: Access violation reading location 0x0000000000000025. occurred Inside boost::python::numpy::intialize() the exception is thrown when trying to execute the line: PyObject *numpy = PyImport_ImportModule("numpy.core.multiarray"); Does anyone know why that would happen or how to debug the issue further? I have installed all packages via pip and executed the python code as described in https://www.scipy.org/getting-started.html. Thanks ahead! Christian

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[python] Linker error when initializing numpy
by Christian Henning 18 Nov '17

18 Nov '17

Hi all, I have the latest boost from the master branch and built everything including python. I can see that two python related libs were built: libboost_python3-vc141-mt-gd-x64-1_66.lib libboost_numpy3-vc141-mt-gd-x64-1_66.lib For compiling python I use vcpkg and it's generating python3_d.lib for debug and python3.lib for release. The cpp code I like to compile is: #include <iostream> #include <boost/python.hpp> #include <boost/python/numpy.hpp> namespace p = boost::python; namespace np = boost::python::numpy; int main() { Py_Initialize(); np::initialize(); return 0; } A few issues: 1) linker is looking for "boost_python3-vc141-mt-gd-x64-1_66.lib" but I got "libboost_python3-vc141-mt-gd-x64-1_66.lib" Please tell me how to fix that. For now I just copied the libboost* files and renamed them. 2) Linker error: "__declspec(dllimport) void __cdecl boost::python::numpy::initialize(bool)" How can I resolve that? Thanks, Christian

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Conan-center package.
by Philippe Groarke 17 Nov '17

17 Nov '17

Are there any plans to release an official Boost package on Conan-Center? If not, any specific reason? It would really help Windows builds and facilitate enterprise adoption. Thank you & good day.

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