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[multi_index] do erase() call key extractors?
by Nick Stokes 25 Dec '15

25 Dec '15

This is probably rather obvious, but I wasn't able to locate this guarantee in MIC docs. Take, struct Foo { explicit Foo(Bar* b = nullptr) : bar(b) {} Bar* bar; }; int getBarValue (const Foo& f) { assert( f.bar ); return f.bar->getValue(); } boost::multi_index< Foo, indexed_by< < hashed_unique < member<Foo, Bar* , &Foo::bar > >> , hashed_non_unique < global_fun<const Foo&, int, &getBarValue >> >> FooIndex; void grill() { FooIndex fooIndex; Bar* b; { auto bWork = make_unique<Bar>(); // ... fooIndex.emplace( bWork.get() ); b = bWork.get(); } fooIndex.erase(b); // ... } Please ignore the fact that raw-pointers are potentially dangerous etc. The question is does erase() call getBarValue() despite the fact I am using the first index? More generally, do key extractors get called *at all* except at the point of insertion? Thanks, Nick

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template error when using multi_index_container
by John M. Dlugosz 25 Dec '15

25 Dec '15

I'm getting a strange template instantiation error with a simple and reasonable use of multi_index_container, which I've written up in detail with a minimal program to reproduce here: http://stackoverflow.com/questions/34450642/why-is-this-member-function-a-d… This showed up in Visual Studio 2015, and has worked just fine for years on VS10 and on other platforms. I've tried updating Boost and new versions don't make any difference. This example was prepared using Boost 1.59, and I see the same thing with 1.60. —John

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[container] Boost 1.60 Release link error
by Hickman, Steve (AdvTech) 24 Dec '15

24 Dec '15

Getting a linker error with the Windows version of Boost on release only (not debug) using v 1.60. This did not show up with 1.58 (I skipped 1.59 so I have no comment on it). I'm using the prebuilt libraries: 8> Creating library D:\GITRepos\fd_x-current_feature\source\Devices\MockDevice\Test\Release\MockTest.lib and object D:\GITRepos\fd_x-current_feature\source\Devices\MockDevice\Test\Release\MockTest.exp 8>MockDevice.lib(Mock.obj) : error LNK2001: unresolved external symbol "public: void __thiscall boost::container::container_detail::has_member_function_named_construct<class boost::container::new_allocator<char> >::BaseMixin::construct(void)" (?construct@BaseMixin@?$has_member_function_named_construct@V?$new_allocator@D@container@boost@@@container_detail@container@boost@@QAEXXZ) 8>MockDevice.lib(Mock.obj) : error LNK2001: unresolved external symbol "public: void __thiscall boost::container::container_detail::has_member_function_named_construct<class boost::container::new_allocator<struct boost::container::container_detail::tree_node<struct std::pair<class boost::container::basic_string<char,struct std::char_traits<char>,class boost::container::new_allocator<char> > const ,struct boost::interprocess::ipcdetail::ref_count_ptr>,void *,0,1> > >::BaseMixin::construct(void)" (?construct@BaseMixin@?$has_member_function_named_construct@V?$new_allocator@U?$tree_node@U?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$new_allocator@D@container@boost@@@container@boost@@Uref_count_ptr@ipcdetail@interprocess@3@@std@@PAX$0A@$00@container_detail@container@boost@@@container@boost@@@container_detail@container@boost@@QAEXXZ) 8>D:\GITRepos\fd_x-current_feature\source\Devices\MockDevice\Test\Release\MockTest.exe : fatal error LNK1120: 2 unresolved externals Steve Hickman System Architect, Human Machine Collaboration Honeywell | Aerospace Office: 480-236-8367 steve.hickman(a)honeywell.com https://in.honeywell.com/sites/aero/Pages/Home.aspx

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Boost 1.60 causes argument-dependent-lookup issues.
by John M. Dlugosz 24 Dec '15

24 Dec '15

See http://stackoverflow.com/questions/34449254/how-is-argument-dependent-looku… I found that code that has worked OK on previous versions of Boost (and does not have this issues with 1.59) is getting unexpected ambiguities in 1.60. Using boost::totally_ordered et al. (even as a private base) appears to be polluting the namespace in which the client class appears. Something like this: class C : boost::totally_ordered<C> { ⋯ } ; using std::make_shared; ⋮ auto p= make_shared<C>(args); this complains that it finds boost::make_shared via argument-dependent lookup, as well as the expected std::make_shared.

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Re: [Boost-users] Race in boost::condition_variable::wait
by Éric Malenfant 23 Dec '15

23 Dec '15

Not sure I understand your question. Unless I'm missing something, the guard in condition_variable::wait does not release the mutex, it is simply there to ensure that it is reacquired on exit. The mutex is released by pthread_cond_wait (atomically with the wait on the condition). Éric Malenfant Le 2015-12-22 8:30 PM, "Chris Stankevitz" <chrisstankevitz(a)gmail.com> a écrit : Hi, Regarding boost::condition_variable::wait (listed below with an obvious modification), It seems to me that there is a race condition because the following operations are not atomic: 1) unlocking of "m" 2) waiting on "cond". Can someone explain to me why boost::condition_variable::wait is not racing the user code in the example below? Thank you, Chris === inline void condition_variable::wait(unique_lock<mutex>& m) { int res=0; { thread_cv_detail::lock_on_exit<unique_lock<mutex> > guard; detail::interruption_checker check_for_interruption(&internal_mutex,&cond); guard.activate(m); #ifdef ENCOURAGE_DEADLOCK boost::this_thread::sleep_for(boost::chrono::seconds(100)); #endif do { res = pthread_cond_wait(&cond,&internal_mutex); } while (res == EINTR); } } === #define ENCOURAGE_DEADLOCK #include <boost/thread.hpp> int main() { boost::mutex Mutex; boost::condition_variable Condition; bool Quit = false; boost::thread Thread([&] { boost::unique_lock<boost::mutex> Lock(Mutex); while (!Quit) { Condition.wait(Lock); } }); boost::this_thread::sleep_for(boost::chrono::seconds(1)); boost::lock_guard<boost::mutex> Lock(Mutex); Quit = true; Condition.notify_all(); return 0; } _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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[boost][iterator] Regarding Ticket #11847
by Gagan Kumar 23 Dec '15

23 Dec '15

Hi, I am new and I wanted to contribute. The ticker #11847 says,"reference typedef no longer available in parent class of iterator_facade" but actually I think reference is available in class iterator_facade itself(boost/iterator/iterator_facade.hpp). But still we are not able to use reference in class simple_iterator : public boost::iterator_facade<simple_iterator<T>, T, boost::forward_traversal_tag> and then after a while I saw this http://stackoverflow.com/questions/1643035/propagating-typedef-from-based-t… >From my side I can only solve this kind of problem by using typename boost::iterators::iterator_facade<simple_iterator<T>, T, boost::iterators::forward_traversal_tag>::reference; or using alternative of reference as T& dereference() const { return *m_iter; } //T& instead of reference, as stated in Ticket Can somebody please tell me or guide me to a better way to solve this problem. Regards Gagan Kumar

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Boost 1.60.0 has been released
by Marshall Clow 23 Dec '15

23 Dec '15

Release 1.60.0 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 one new library and numerous enhancements and bug fixes for existing libraries. New Libraries * VMD: Variadic Macro Data library, from Edward Diener For details, including download links, see http://www.boost.org/users/news/version_1.60.0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.60.0/ Tom Kent has made pre-built windows binaries, and they are available at: https://sourceforge.net/projects/boost/files/boost-binaries/1.60.0/ 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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Race in boost::condition_variable::wait
by Chris Stankevitz 23 Dec '15

23 Dec '15

Hi, Regarding boost::condition_variable::wait (listed below with an obvious modification), It seems to me that there is a race condition because the following operations are not atomic: 1) unlocking of "m" 2) waiting on "cond". Can someone explain to me why boost::condition_variable::wait is not racing the user code in the example below? Thank you, Chris === inline void condition_variable::wait(unique_lock<mutex>& m) { int res=0; { thread_cv_detail::lock_on_exit<unique_lock<mutex> > guard; detail::interruption_checker check_for_interruption(&internal_mutex,&cond); guard.activate(m); #ifdef ENCOURAGE_DEADLOCK boost::this_thread::sleep_for(boost::chrono::seconds(100)); #endif do { res = pthread_cond_wait(&cond,&internal_mutex); } while (res == EINTR); } } === #define ENCOURAGE_DEADLOCK #include <boost/thread.hpp> int main() { boost::mutex Mutex; boost::condition_variable Condition; bool Quit = false; boost::thread Thread([&] { boost::unique_lock<boost::mutex> Lock(Mutex); while (!Quit) { Condition.wait(Lock); } }); boost::this_thread::sleep_for(boost::chrono::seconds(1)); boost::lock_guard<boost::mutex> Lock(Mutex); Quit = true; Condition.notify_all(); return 0; }

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Not for publishing
by Soul Studios 22 Dec '15

22 Dec '15

To whoever it is that's been blocking my posts to the mailing list - with the exception of this email, please stop. I have chronic fatigue syndrome, and I feel like I'm fighting an uphill battle against the lack of documentation around actually doing documentation for boost. I would've understood if I'd said anything reasonably offensive, but I don't think I did.

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Software Freedom Conservancy Support
by Jon Kalb 22 Dec '15

22 Dec '15

This is not a technical message, but instead focuses on Boost Administration. Software Freedom Conservancy in a Financial Fight for its Life Software Freedom Conservancy, the non-profit home of Boost is facing an existential threat. Historically, Conservancy has been funded by corporate donations. This works great when it works, but a management shake-up, change in priorities, or a bad quarter at a large donor can derail the organization¹s programs. It has become obvious that Conservancy must move to a Supporter-driven funding model, where individuals who believe in Conservancy¹s mission of supporting open source projects, such as Boost, make a personal commitment to support that effort. Conservancy's fundraiser, found at https://sfconservancy.org/supporter/, is centered around asking individuals who care about the work that Conservancy does to donate $120/year, or just $10/month, to support the organization. Conservancy seeks about 2,500 Supporters to continue its current work, and 750 Supporters to continue a ³bare minimum² of services to its projects. What does this mean to Boost? Boost receives a myriad of important services (see https://sfconservancy.org/members/services/ ) from Conservancy. We¹ve relied on Conservancy since 2007 to provide them. Here are some of the things that Conservancy does for Boost that are in the ³bare minimum² category: * Dealing with all the financial and contractual details regarding our annual C++ Now conference. It was BoostCon that brought Boost and Conservancy together. C++Now 2016 will the the tenth annual BoostCon and it is a tribute to what we¹ve accomplished working together. * Handle our Google Summer of Code payments and travel, including handling all financial transactions with Google to receive and then disperse the money. * Coordinating travel reimbursements for Boost contributors (both developers and students) to attend conferences. * Receiving and tracking all donations to Boost. * Keeping the non-profit status for us so that we don't have to form our own org and file our own paperwork. As the Chair of the Boost Steering Committee, I cannot overstate how important this is to our existence as an organization. Here are some of the services Boost has received in the wider category: * Dealing with questions from the community (including license-governing bodies like OSI) about Boost's license. * Discussing the issue of copyright governance and contributions with large corporations who want their employees to contribute to Boost but need legal assurances or have questions relating to Boost's license or contribution policies. * Reviewing and handling licensing terms of third-party software that relate to Boost in some way, and giving us feedback and answers about issues related to it. * General legal consulting on issues that we run into as an open source non-profit. As you can see, Boost really relies on the important work of Conservancy. Support from Boost Boost, like all of Conservancy¹s projects, contributes 10% of our revenue to Conservancy¹s general fund. (The other 90% is maintained and administered by Conservancy at the direction of the Boost Steering Committee to advance the Boost project.) But that 10% of revenue from all Conservancy¹s member projects doesn¹t add up to enough to even employee one full time person, let alone the already overworked staff of three that Conservancy has. Donors must make up the difference. When Conservancy launched its fundraising effort, I sent out a request to past BoostCon/C++Now attendees asking for support and I¹m proud and delighted to say that a number of Boost community members have already stepped up. One told me that her company will be matching her support. Boost is one of Conservancy¹s oldest and largest projects, so it is right that Boost community members make up a fair proportion of its supporters. I encourage you to choose Conservancy as one of your charitable gifts this holiday season. (Conservancy is a 501(c)(3) charity incorporated in New York, and donations are typically deductible on U.S. taxes.) Please visit: https://sfconservancy.org/supporter/ If you are able to join the others from the Boost community that are making this gift, please let me know. I¹d like to personally thank you. Jon Kalb Chair, Boost Steering Committee

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