November 2014 - Boost-users - lists.preview.boost.org

Boost.Python shared_ptr bug?
by Christoff Kok 10 Nov '14

10 Nov '14

Hi, I found an issue when accessing a shared_ptr C++ object in Python using Boost.Python. When I try to access an attribute of the shared_ptr object read from an C++ object, I get an error telling me that the attribute does not exist. When I use raw pointers instead of shared_ptr, then there is no issue. Also, when using raw pointers, accessing an item in a list of base class objects returns the object in as the derived most class. This is wanted. When I use shared_ptrs however, the derived most object is of the base class type. This is not wanted. I am sure the Boost.Python developers should be aware of these two issues by now. If so, is there any plans to fix this? If so, when? Below is a test showing this issue: *Raw pointers:* #include<memory> #include<vector> struct Vehicle{ virtual ~Vehicle(){} int testAttribute; }; struct Boat: public Vehicle { virtual ~Boat(){} int testBoatAttribute; }; struct Garage { std::vector<Vehicle*>& vehicleList() { return m_VehicleList; } std::vector<Vehicle*> m_VehicleList; }; #include <boost/python.hpp> #include <boost/python/suite/indexing/vector_indexing_suite.hpp> BOOST_PYTHON_MODULE(garage_ext) { using namespace boost::python; class_<Garage>("Garage") .def("vehicleList", &Garage::vehicleList, return_internal_reference<1>()); class_<Vehicle,Vehicle*,boost::noncopyable>("Vehicle", no_init) .def_readwrite("testAttribute", &Vehicle::testAttribute); class_<Boat,Boat*,bases<Vehicle>>("Boat") .def_readwrite("testBoatAttribute", &Boat::testBoatAttribute); implicitly_convertible<Boat*, Vehicle*>(); class_<std::vector<Vehicle*> >("stl_vector_Vehicle_ptr") .def(vector_indexing_suite<std::vector<Vehicle*>>()); } *Shared pointers:* #include<memory> #include<vector> #include <boost/shared_ptr.hpp> struct Vehicle{ virtual ~Vehicle(){} friend bool operator==(const Vehicle& lhs, const Vehicle& rhs) { return true; } int testAttribute; }; struct Boat: public Vehicle { virtual ~Boat(){} friend bool operator==(const Boat& lhs, const Boat& rhs) { return true; } int testBoatAttribute; }; struct Garage { friend bool operator==(const Garage& lhs, const Garage& rhs) { return true; } std::vector<boost::shared_ptr<Vehicle>>& vehicleList() { return m_VehicleList; } std::vector<boost::shared_ptr<Vehicle>> m_VehicleList; }; #include <boost/python.hpp> #include <boost/python/suite/indexing/vector_indexing_suite.hpp> BOOST_PYTHON_MODULE(garage_ext){ using namespace boost::python; class_<Garage>("Garage") .def("vehicleList", &Garage::vehicleList, return_internal_reference<1>()); class_<Vehicle,boost::shared_ptr<Vehicle>,boost::noncopyable>("Vehicle", no_init) .def_readwrite("testAttribute", &Vehicle::testAttribute); class_<Boat,boost::shared_ptr<Boat>, bases<Vehicle>>("Boat") .def_readwrite("testBoatAttribute", &Boat::testBoatAttribute); implicitly_convertible<boost::shared_ptr<Boat>, boost::shared_ptr<Vehicle>>(); class_<std::vector<boost::shared_ptr<Vehicle>> >("stl_vector_Vehicle_ptr") .def(vector_indexing_suite<std::vector<boost::shared_ptr<Vehicle>>>()); } *Python test:* from garage_ext import * g = Garage() l = g.vehicleList() newboat = Boat() newboat.testAttribute = 3 newboat.testBoatAttribute = 5 l.append(newboat) print(type(l[0])) print(str(hasattr(l[0],"testAttribute"))) print(str(l[0].testAttribute)) b = l[0] print(type(b)) print(str(b.testBoatAttribute)) print("Done.") *Raw pointer result:* <class 'garage_ext.Boat'> True 3 <class 'garage_ext.Boat'> 5 Done. *Shared pointer result:* <class 'garage_ext.*Vehicle*'> *// Expected it to be Boat as with Raw pointers* Traceback (most recent call last): File "test_garage.py", line 9, in <module> print(str(hasattr(l[0],"testAttribute"))) *// Expected attribute to exist as with Raw pointers. Note: dir(l[0]) shows that it has the attribute. Accessing the attribute however throws an error.* Boost.Python.ArgumentError: Python argument types in None.None(Vehicle) did not match C++ signature: None(Vehicle {lvalue}) Kind Regards, Christoff

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MSM library: documentation graphics
by Ricardo Cruz 09 Nov '14

09 Nov '14

Dear all, I am considering adopting boost MSM library for the statecharts in my project. It looks awesome. The documentation has several graphical representations of the state machines: http://www.boost.org/doc/libs/1_57_0/libs/msm/doc/HTML/index.html They look automatically generated. Are they? If so, what tool was used? I did not find that information anywhere in the documentation. Sorry if I miss it. Best wishes, Ricardo Cruz

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Bidirectional breadth first search?
by Amanda Robson 08 Nov '14

08 Nov '14

Hi Does anyone know if Boost already supports bidirectional breadth first search? If not, how feasible would it be to extend boost’s bfs implementation to become bidirectional? Thanks. Amanda

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iterator adaptor not inheriting pointer typedef
by Matei David 08 Nov '14

08 Nov '14

Hi, I have some questions about the Boost Iterator library. I've recently discovered the "hard way", meaning through impenetrable TMP error messages :), that when using boost::iterator_adaptor, the derived iterator type does not (always??) inherit the pointer typedef of the base iterator type. I mean, the iterator_adaptor glue class does not have this typedef. So, for example, I have a Base_Iterator type with: Base_Iterator::pointer != Base_Iterator::value_type* If I do: class Derived_Iterator : public boost::iterator_adaptor< Derived_Iterator, Base_Iterator > {...} then, strangely I find: Derived_Iterator::value_type == Base_Iterator::value_type (OK) Derived_Iterator::pointer == Base_Iterator::value_type* != Base_Iterator::pointer (not OK) I looked at the documentation, and I did find a mention of this, but only for iterator_facade, here: http://www.boost.org/doc/libs/develop/libs/iterator/doc/iterator_facade.html The corresponding page for iterator_adaptor does not mention the pointer typedef at all. While for facade using a plain pointer seems ok (no other reasonable default), I would argue that for adaptor this is not ok. Is this expected behaviour or a bug? Within the same setting, and in what could be a related issue, I also found that the intermediate boost::iterator_adaptor<> class does not seem to contain the default/common sense definition: Base_Iterator operator->() const { return this->base(); } I didn't look inside the source code of boost::iterator_adaptor, but I found a situation where I have to put this definition explicitly inside Derived_Iterator for my code to compile (without it, it doesn't). Does this sound like expected behaviour? Thanks M

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Flyweight: constexpr user defined literals
by Akim Demaille 07 Nov '14

07 Nov '14

Hi all, Hi Joaquin, I'm using flyweights of strings (aka symbols) for my "format" arguments: a key that specifies the kind of output that should be produced by the printing routines. Sometimes, I have code that roughly resembles to: print_entry_(src, dst, o, dot2tex_ ? symbol("latex") : symbol("text")); My question is: do we have constexpr constructors with Flyweight in such a way that I could have something like: print_entry_(src, dst, o, dot2tex_ ? "latex"sym : "text"sym); and have a single construction of these guys not matter how many times I go throw this piece of code, or should I build them once for all in say a member? print_entry_(src, dst, o, dot2tex_ ? sym_latex : sym_text); I've seen nothing about "constexpr" in the doc.

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Re: [Boost-users] iterator_facade Boost 1.57
by Matei David 07 Nov '14

07 Nov '14

On Tue, 04 Nov 2014 14:07:09 +0000 (UTC) gast128 wrote: > Dear all, > > Just trying out 1.57, since we are already 5 releases behind due to > all kinds of compilation errors with Boost and our software. Below > simplified code doesn't compile on vs2010: > > template <typename DerivedType> > struct IteratorFacade : public boost::iterator_facade<DerivedType, > int, std::random_access_iterator_tag> > { > typedef boost::iterator_facade<DerivedType, int, > std::random_access_iterator_tag> base; > > IteratorFacade (); > virtual ~IteratorFacade (); > > friend class boost::iterator_core_access; > > reference dereference () const; > }; > > struct MyIteratorFacade : IteratorFacade<MyIteratorFacade> > { > }; > > What do I wrong? Hi, I'm gcc 4.9.1 on Ubuntu 14.04. The reason this doesn't compile is that the "reference" typedef is contained in the glue class boost::iterator_facade, which is a base class of IteratorFacade<MyIteratorFacade>. When you write "reference" inside the later, the name is not being looked up in the base class. So you should write: typename base::reference dereference() const; If you want to use "reference" in many places in IteratorFacade<>, pull the typedef from its base with: typedef typename base::reference reference; or, if using C++11: using typename base::reference; Note: whether you pull it up or not, you can always get the typedef as IteratorFacade<...>::reference, or MyIteratorFacade::reference in your case. (See the example below, where I'm not pulling it up, but I can still find it.) I would also add the observation that your construct creates an unusual derivation. Usually, the iterator class you want to define has boost::iterator_facade as its direct base. In your case, boost::iterator_facade is the base of the base of your iterator class (so, 2 levels down): MyIteratorFacade : IteratorFacade<MyIteratorFacade> : boost::iterator_facade<MyIteratorFacade, ...> I'm not sure this would cause any problems, just be on the lookout for missing constructors. For example, this compiles just fine for me: #include <type_traits> #include <boost/iterator/iterator_facade.hpp> struct MyIteratorFacade : public boost::iterator_facade<MyIteratorFacade, int, std::random_access_iterator_tag> { typedef boost::iterator_facade<MyIteratorFacade, int, std::random_access_iterator_tag> base; MyIteratorFacade (); virtual ~MyIteratorFacade (); friend class boost::iterator_core_access; typename base::reference dereference() const; }; static_assert(std::is_same< MyIteratorFacade::value_type, int >::value, "MyIteratorFacade::value_type != int"); static_assert(std::is_same< MyIteratorFacade::reference, int& >::value, "MyIteratorFacade::reference != int&"); static_assert(std::is_same< MyIteratorFacade::pointer, int* >::value, "MyIteratorFacade::pointer != int*"); static_assert(std::is_same< std::iterator_traits<MyIteratorFacade>::value_type, int >::value, "iterator_traits<MyIteratorFacade>::value_type != int"); static_assert(std::is_same< std::iterator_traits<MyIteratorFacade>::reference, int& >::value, "iterator_traits<MyIteratorFacade>::reference != int&"); static_assert(std::is_same< std::iterator_traits<MyIteratorFacade>::pointer, int* >::value, "iterator_traits<MyIteratorFacade>::pointer != int*"); I compile with: g++ -Wall -Wextra -pedantic -std=c++11 -I${BOOST_INCLUDE_1_57} -c (I'm only using c++11 for static_assert.) M

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Boost.Python C++ pointer object to python: Attribute does not exist.
by Christoff Kok 07 Nov '14

07 Nov '14

Hi, I'm struggling with the following issue in a boost.python implementation: I have a list of std::shared_ptr in C++, I am accessing this list from Python. - When I access an element in the list, the elements does not have any attributes apparently. I get an error trying to access an attribute, hasattr returns false on the attribute, but dir informs me that it exist. - When I change the C++ implementation from shared_ptr to raw ptr's everything works as expected. - I want to use shared_ptrs for what I feel: obvious reasons. Below is the C++ code and the Python code. ################### ### garage_ext.cpp ### ################### #include<memory> #include<vector> namespace boost { template<class T> T* get_pointer(std::shared_ptr<T>& p){ return p.get(); }} struct Vehicle{ virtual ~Vehicle(){} friend bool operator==(const Vehicle& lhs, const Vehicle& rhs) { return true; } int testAttribute; }; struct Boat: public Vehicle { virtual ~Boat(){} friend bool operator==(const Boat& lhs, const Boat& rhs) { return true; } int testBoatAttribute; }; struct Garage { friend bool operator==(const Garage& lhs, const Garage& rhs) { return true; } std::vector<std::shared_ptr<Vehicle>>& vehicleList() { return m_VehicleList; } std::vector<std::shared_ptr<Boat>>& boatList() { return m_BoatList; } std::vector<std::shared_ptr<Vehicle>> m_VehicleList; std::vector<std::shared_ptr<Boat>> m_BoatList; }; #include <boost/python.hpp> #include <boost/python/suite/indexing/vector_indexing_suite.hpp> class BoatWrap : public Boat, public boost::python::wrapper<Boat> { public: static std::shared_ptr<Boat> cast(std::shared_ptr<Vehicle> const& v) { return std::dynamic_pointer_cast<Boat>(v); } }; BOOST_PYTHON_MODULE(garage_ext) { using namespace boost::python; class_<Garage>("Garage") .def("vehicleList", &Garage::vehicleList, return_internal_reference<1>()) .def("boatList", &Garage::boatList, return_internal_reference<1>()) ; class_<Vehicle, std::shared_ptr<Vehicle>,boost::noncopyable>("Vehicle", no_init) .def_readwrite("testAttribute", &Vehicle::testAttribute) ; class_<BoatWrap,std::shared_ptr<Boat>,bases<Vehicle>>("Boat") .def("cast", &BoatWrap::cast) .staticmethod("cast") .def_readwrite("testBoatAttribute", &Boat::testBoatAttribute) ; implicitly_convertible<std::shared_ptr<Boat>,std::shared_ptr<Vehicle>>(); class_<std::vector<std::shared_ptr<Vehicle>> >("stl_vector_Vehicle_ptr") .def(vector_indexing_suite<std::vector<std::shared_ptr<Vehicle>> >()); class_<std::vector<std::shared_ptr<Boat>> >("stl_vector_Boat_ptr") .def(vector_indexing_suite<std::vector<std::shared_ptr<Boat>> >()); } ##################### ### Python test code ### ##################### g = Garage() l = g.boatList() newboat = Boat() l.append(newboat) boatFromList = l[0] print(type(boatFromList)) print(str(hasattr(newboat,"testBoatAttribute"))) dir(boatFromList) # The following line throws the error. print(str(hasattr(boatFromList,"testBoatAttribute"))) I created a cast method for boat. If I cast l[0] to Boat using: boatFromList = Boat.cast(l[0]) print(str(hasattr(boatFromList,"testBoatAttribute"))) works. This is all very strange to me. It feels very buggy. Could someone please help me clarify the reason for this behavious? Regards, Christoff

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reference_wrapper on Boost 1.57
by gast128 06 Nov '14

06 Nov '14

This gives also a compilation error on vs2010: void F() { boost::reference_wrapper<float (* const)(float)> wrap(&cosf); //std::reference_wrapper<float (* const)(float)> wrap(&cosf); //ok } 1>KTestCuj2005June1.cpp(182): error C2248: 'boost::reference_wrapper<T>::reference_wrapper' : cannot access private member declared in class 'boost::reference_wrapper<T>' 1> with 1> [ 1> T=float (__cdecl *const )(float) 1> ] 1> C:\work sdk\boost_1_57_0\boost/core/ref.hpp(85) : see declaration of 'boost::reference_wrapper<T>::reference_wrapper' 1> with 1> [ 1> T=float (__cdecl *const )(float) 1> ] ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

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Boost on Google+
by Vladimir Prus 06 Nov '14

06 Nov '14

Hi, I've created a Google+ community for Boost, and everybody is welcome to join here: https://plus.google.com/communities/106814259809358442744 I don't have any great plan here, but a lot of tech people are active on G+, so why not? -- Vladimir Prus CodeSourcery / Mentor Embedded http://vladimirprus.com

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boost 1.57: MS VS2008: unknown pragma in type_index.hpp
by Andreas Wehrmann 05 Nov '14

05 Nov '14

Hi! I've just compiled boost 1.57 with MS VS2008 x86 and this warning came all over the place: main\lib\boost_1_57_0\boost\type_index.hpp(37) : warning C4068: unknown pragma Still, the compilation went fine and everything seems to work as usual. It's just somewhat annoying because this warning pops up very often when I compile my applications. Regards, Andreas

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[Optional] Possible bug with VS2008
by dariomt＠gmail.com 05 Nov '14

05 Nov '14

Hi, The following minimal test case does not compile with VS2008 (using Boost 1.55) #include <boost/optional.hpp> struct A { int T; }; int main() { boost::optional<A> a; } The error is, edited for clarity: boost\optional\optional.hpp(479) : error C2523: 'A::~T' : destructor tag mismatch boost\optional\optional.hpp(479) : while compiling class template member function 'void boost::optional_detail::optional_base<T>::destroy_impl(boost::optional_detail::optional_base<T>::is_not_reference_tag)' with [ T=A ] boost\optional\optional.hpp(500) : see reference to class template instantiation 'boost::optional_detail::optional_base<T>' being compiled with [ T=A ] main.cpp(8) : see reference to class template instantiation 'boost::optional<T>' being compiled with [ T=A ] After much head-scratching, I found out the culprit: the name of the integer member!! The compiler confuses the name of member 'T' with the name of the template parameter 'T' when trying to invoke its destructor... The offending code is void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->T::~T() ; m_initialized = false ; } Given that I cannot change struct A, is there a way to fix this? Is this a compiler bug or a Boost.Optional bug? Thanks in advance!

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Spirit with UI Tools
by Philipp Kraus 05 Nov '14

05 Nov '14

Hello, I would like to create a small parser with Boost.Spirit. I have run the short examples and everything works well, so I would like to create my own LL grammar. In my case I need also for documentation a EBNF or something else and in the best case I can would like to create the EBNF first and transform this into the Spirit LL grammar code. Did you know any tools to do this? My first idea is to use AntLR to create the grammar but imho it creates a LR grammar. Can you recommend a tool to define the grammar structure and generate the Spirit code? Thanks a lot Phil

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Boost.Variant on Boost 1.57
by gast128 04 Nov '14

04 Nov '14

hello all, I get a compilation error with Boost.Operators and boost.Variant on vs2010: struct KFoo : boost::totally_ordered<KFoo> { }; bool operator<(const KFoo&, const KFoo&); bool operator==(const KFoo&, const KFoo&); void Foo() { boost::variant<KFoo> var; var.swap(var); } 1>C:\work sdk\boost_1_57_0\boost/variant/detail/move.hpp(60): error C2668: 'boost::swap' : ambiguous call to overloaded function 1> C:\work sdk\boost_1_57_0\boost/core/swap.hpp(54): could be 'void boost::swap<T,T>(T1 &,T2 &)' [found using argument-dependent lookup] 1> with 1> [ 1> T=T0, 1> T1=T0, 1> T2=T0 1> ] 1> C:\work sdk\boost_1_57_0\boost/variant/detail/move.hpp(44): or 'void boost::detail::variant::move_swap_fallback::swap<T,T>(T1 &,T2 &)' anyone?

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bjam building with error
by NtVisigoth 04 Nov '14

04 Nov '14

Hello, I cannot compile bjam.exe and I see error. I have googled and I see my trouble here: Name: "Build.bat does not autodetect msvc on 64-bit Windows when building bjam" URL: https://svn.boost.org/trac/boost/ticket/1091 To reproduce: 0. cd <boos libraries directory> 1. Start cmd.exe. 2. Then start bootstrap.bat I see: d:\projects\cpp-workspace\boost-libraries>bootstrap.bat Building Boost.Build engine \\Vim\\vim74\\";c:\portable-programs\adt-bundle-windows-x86_64\sdk\\platform-tools;c:\portable-progr ams\adt-bundle-windows-x86_64\sdk\\tools" was unexpected at this time. d:\projects\cpp-workspace\boost-libraries\tools\build\src\engine> What can I do to compile bjam ?

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problem with #include <boost/thread.hpp>
by Grison PG Pierre (External DEXIA-US) 04 Nov '14

04 Nov '14

Hello, I encounter a problem with the Thread library. The library works fine when I use it in a .exe project. It means it has been correctly built. Then I try to use the same library in an DLL project (so as to build a XLL object thanks to the XLW library). But as soon as I add the line #include <boost/thread.hpp> to my project, even if it compile without any problem, I get the following message when I debug my project through Excel: The file you are trying to open, "mylibrary.xll" is in a different format than specified by the file extension, Verify that the file is not corrupted [...]. Do you want to open the file now? And I can no more use my C++ functions in Excel. Do you have already encounter this problem? I use VS2010. I have tried both Multi-threaded Debug DLL (/MDd) and Multi-threaded DLL (/MD) options. My solution includes two other static libraries and also with the classic RunInterfaceGenerator XLW-project (the one which is executed when debugging). Regards, Pierre

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iterator_facade Boost 1.57
by gast128 04 Nov '14

04 Nov '14

Dear all, Just trying out 1.57, since we are already 5 releases behind due to all kinds of compilation errors with Boost and our software. Below simplified code doesn't compile on vs2010: template <typename DerivedType> struct IteratorFacade : public boost::iterator_facade<DerivedType, int, std::random_access_iterator_tag> { typedef boost::iterator_facade<DerivedType, int, std::random_access_iterator_tag> base; IteratorFacade (); virtual ~IteratorFacade (); friend class boost::iterator_core_access; reference dereference () const; }; struct MyIteratorFacade : IteratorFacade<MyIteratorFacade> { }; What do I wrong?

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Re: [Boost-users] Boost 1.57.0 has been released
by Tom Kent 04 Nov '14

04 Nov '14

> > Release 1.57.0 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 no new libraries and numerous enhancements and bug > fixes for existing libraries. > For details, including download links, see > http://www.boost.org/users/news/version_1.57.0 > You can also download directly from SourceForge: > http://sourceforge.net/projects/boost/files/boost/1.57.0/ > 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 > Vladimir Prus > Rene Rivera > Marshall Clow > Eric Niebler > Daniel James > Beman Dawes The corresponding windows binaries for msvc-8.0 (SP1), msvc-9.0 (SP1), msvc-10.0 (SP1), msvc-11.0 (Update 4) and msvc-12.0 (Update 3) in 32 & 64 bit versions are now also available from sourceforge. https://sourceforge.net/projects/boost/files/boost-binaries/1.57.0/ Tom Kent

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Re: [Boost-users] [Boost-announce] Boost 1.57.0 has been released
by Marshall Clow 04 Nov '14

04 Nov '14

> Hi Marshall, > > I wonder if the "Beta Issues” section on the release notes page (http://www.boost.org/users/history/version_1_57_0.html) is correct,… Looks like a copy-paste leftover from the beta version. Several people reported this. Thank you. It has been fixed. — Marshall

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Boost 1.57.0 has been released
by Marshall Clow 03 Nov '14

03 Nov '14

Release 1.57.0 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 no new libraries and numerous enhancements and bug fixes for existing libraries. For details, including download links, see http://www.boost.org/users/news/version_1.57.0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.57.0/ 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 Vladimir Prus Rene Rivera Marshall Clow Eric Niebler Daniel James Beman Dawes

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[Test] How to log output to both stdout in HRF and to a file in XML?
by Martin Ba 03 Nov '14

03 Nov '14

As asked on SO: http://stackoverflow.com/questions/26505229/how-to-log-boost-test-output-to… I would like to enable logging of Boost.Test output to *both* the stdout/sterr and to a logfile. However, I would also like to have the stdout logging be in HumanReadableFormat and only the file output be in XML format. Generating a report file seems to be addressed [here][1]. ([official docs][2]) Choosing the format can be done in [various ways][3], but it seems one is stuck with either HRF or XML? ----------- Rationale: When running tests on or [Jenkins][4] server, the [xUnit plugin][5] [requires][6] the **log** XML output (as opposed to the *report* XML output -- `log_level` vs. `report_level`). However, the in-progress log output (in HRF) is highly valuable *while* the tests are running on the server, to detect hanging tests or to a quick manual check of where the tests currently are. So I want an in-progress HRF log for the tests and at the end I need an XML file containing the `<TestLog>...</TestLog>` output of Boost.Test (not the `<TestResult>` output). Do note that we run both unit as well as integration tests via Boost.Test, so some of them are quite long-running. [1]: http://stackoverflow.com/questions/3786639/what-is-the-better-way-to-genera… [2]: http://www.boost.org/doc/libs/1_44_0/libs/test/doc/html/utf/user-guide/test… [3]: http://www.boost.org/doc/libs/1_44_0/libs/test/doc/html/utf/user-guide/runt… [4]: http://jenkins-ci.org/ [5]: https://wiki.jenkins-ci.org/display/JENKINS/xUnit+Plugin [6]: https://issues.jenkins-ci.org/browse/JENKINS-13686

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ASIO: Windows/Linux/Mac socket inter-operability
by Joost Kraaijeveld 03 Nov '14

03 Nov '14

Hi, I have a C/S-application that uses ASIO-sockets. The application runs fine if I try to connect between 2 Windows or 2 Linus or 2 Mac machineas. However, it fails to work with a "reset by peer" error if I try to connect between Windows and Linux, Windows and Mac or Linux and Mac. Is there anything known about problems wrt inter-os connections, and if so, is there a solution for this? TIA -- Groeten, Joost Kraaijeveld Molukkenstraat 14 6524NB Nijmegen tel: 024-3607445 / 06-51855277

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Boost IOStream - Buffer as an input stream
by Lloyd 03 Nov '14

03 Nov '14

Hi, We am trying to use a buffer as an input stream. For that we have used "basic_array_source" like this boost::iostreams::basic_array_source<BYTE> source(mem_ptr,size); boost::iostreams::stream<boost::iostreams::basic_array_source <BYTE>> streamReader; streamReader.open(source, std::ios::binary); But this method does not give input-stream related methods (functions like seekg), instead it give methods related to output stream (seekp). Can you please tell what is wrong with this approach? Thanks, Lloyd

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[1.57.0] Release candidates available
by Marshall Clow 03 Nov '14

03 Nov '14

[ Please disregard previous message; apparently I am brain-dead this morning. The uploaded files are correct, though. ] Release candidate files for 1.57.0 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: MD5 (./boost_1_57_0_rc1.7z) = 17c98dd78d6180f553fbefe5a0f57d12 MD5 (./boost_1_57_0_rc1.tar.bz2) = 1be49befbdd9a5ce9def2983ba3e7b76 MD5 (./boost_1_57_0_rc1.tar.gz) = 25f9a8ac28beeb5ab84aa98510305299 MD5 (./boost_1_57_0_rc1.zip) = 5e040e578e3f0ba879da04a1e0cd55ff Thanks! -- The release managers P.S. Release notes are here: http://www.boost.org/users/history/version_1_57_0.html

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[Asio] null_buffer behaviors
by lin li 03 Nov '14

03 Nov '14

Hi, guys. In the doc of asio, it says 'A null_buffers operation doesn't return until the I/O object is "ready" to perform the operation'. But when I use it on a server side socket, i.e. a socket created by "accept" call when a new connection has arrived. It seems to return immediately even the other end has not started to send the data yet. Is this normal?

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How to know whether a boost heade has been included?
by Vincenzo Romano 03 Nov '14

03 Nov '14

I thought I could check for the symbol BOOST_VERSION to be defined. But, as of v1.55, it's not the case at least for the <boost/any.hpp> header. Any hint? Thanks in advance.

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[boost.variant] accessing variant with pattern-matching instead of visitors
by Roger 02 Nov '14

02 Nov '14

Hi! The CppCon 2014, Yuriy Solodkyy had an interesting talk "Accept no visitors"(*). It presents an alternative accessing technique for variant data-type. It basically use pattern matching syntax, similar to that in functional languages, instead of visitors. I think this would be a great benefit for boost::variant data-type... being able to access variables from the same scope, group states similar in behavior, and take care of the loop unrolling for dispatching oneself. Especially when using variant as polymorphism, like the other interesting CppCon 2014 talking, Jason Lucas "Polymorphism with Unions" (**) covered. Would it be worth to implement a tiny pattern-matching library for boost::variant itself? Has anyone elaborated with this? Thanks for any hints! /perrog * Yuriy Solodkyy "Accept no visitors, http://youtu.be/QhJguzpZOrk ** Jason Lucas "Polymorphism with Unions", http://youtu.be/uii2AfiMA0o

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(no subject)
by Johnny McCullough 01 Nov '14

01 Nov '14

I'm new to boost, and I'm wondering about the best / most efficient way to transfer a large dataset via boost::asio. I've retrieved a datasetfrom a database (Cassandra) and I'm using boost asio to provide a network service that responds to queries. So I have a client socket and a dataset. I have to iterate the dataset, perform some simple formatting (e.g. csv, json, xml), then write it out to the client socket. But there's a lot of data. Perhaps gigabytes. So my initial thoughts were the producer / consumer pattern - the producer writing to a streambuf and the consumer async_write-ing it out to the client's socket. But I'm not sure this is a good approach - I know that streambuf isn't threadsafe and so managing the streambuf with locks may well become a performance bottleneck. Obviously, I don't want to replicate what may be gigabyte(s) of data from a resultset into a buffer just so it can be written out to a socket, So should I write this data synchronously straight to the socket instead? What's the best approach to solving this kind of problem? thanks for your consideration

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