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[TypeErasure] Similar simple class.
by Arman Hunanyan 23 Dec '12

23 Dec '12

Hi All, I have implemented xany class https://sourceforge.net/projects/extendableany/?source=directory. Then I noticed that there is a Boost.TypeErasure library which allows to do same as xany does and something more. Implementation of class xany has 1005 lines and it is implemented and tested in a week. Of course xany isn't comparable with Boost.TypeErasure, but it may be interesting to look. Below is a definition of same method for Boost.TypeErasure and for xany. // definition of push_back for Boost.TypeErasure template<class C, class T> struct push_back { static void apply(C& cont, const T& arg) { cont.push_back(arg); } }; namespace boost { namespace type_erasure { template<class C, class T, class Base> struct concept_interface< ::push_back<C, T>, Base, C> : Base { void push_back(typename rebind_any<Base, const T&>::type arg) { call(::push_back<C, T>(), *this, arg); } }; } } any<push_back<_self, int>, _self&> c; // definition of push_back for xany template <typename Xany, typename T> struct push_back_method { typedef void (Xany::* signature) (const T&); template <typename B> struct wrapper : public B { void push_back(const T& e) { this->call(push_back_method(), e); } }; struct implementation { template <typename Container> void operator() (Container& c, const T& e) { c.push_back(e); } }; }; xany<boost::mpl::vector<push_back_method<boost::mpl::_1, int> > > c; xany requires additional signature type to be specified. This allows to use dispatching in implementation. struct implementation { void operator() (OtherCodingStyleContainer& c, const T& e) { c.PushBack(e); } template <typename Container> void operator() (Container& c, const T& e) { c.push_back(e); } }; Documentation contains more examples.

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[Inspect] hadn't run since... August
by Artyom Beilis 23 Dec '12

23 Dec '12

Boost.Inspect hadn't run on trunk or release sinse august: From: http://beta.boost.org/development/testing.html trunk - http://boost.cowic.de/rc/inspect-trunk.html release - http://boost.cowic.de/rc/inspect-snapshot.html Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/

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[atomic, x86] need another pair of eyes
by Tim Blechmann 23 Dec '12

23 Dec '12

hi all, i need another pair of eyes regarding boost.atomic on x86: the implementation of memory barrier is merely a compiler barrier, but not a CPU barrier, as it is using code like: __asm__ __volatile__ ("" ::: "memory"); afaict, one should use a `real' CPU barrier like "mfence" or "lock; addl $0,0(%%esp)". is this correct? apart from that, i've seen that compare_exchange is using explicit memory barriers before/after "cmpxchg" instructions. i somehow though that cmpxchg and the 8b/16b variants implicitly issue a memory barrier, so the resulting code would generate multiple memory barriers. can someone with some insights in the x86 architecture confirm this? thanks, tim

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Re: [boost] Boost SIMD beta release
by Brian Wood 23 Dec '12

23 Dec '12

From: Mathias Gaunard: On 20/12/2012 20:34, Dave Abrahams wrote: >> Yes; there's a runtime test. > > Let's put a runtime test at every step of our critical loop, sounds like > a good idea. > I actually somewhat looked into this, and in this case segmented > iterators don't allow any optimization compared to normal iterators. I think less sarcasm would be helpful. >> I'm afraid you have not been specific enough about the >> problem you claim to see for me to be able to evaluate >> whether it exists or not. > > I'm afraid you're the one trying to make everything fit into this > model you've somehow taken a liking to. I'd prefer to focus on results rather than motives. Shalom Brian Ebenezer Enterprises http://webEbenezer.net (651) 251-9384

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[BTREE] Get BTREE library into boost - Market Research
by Joel Young 22 Dec '12

22 Dec '12

My organization is investigating contracting for enhancements to the boost::btree library developed by Beman Dawes with all enhancements to remain under the boost license and author(s) retaining all copyright. No travel is expected to be required as part of this project. We are considering the following enhancements: 1. Develop detailed developer and tutorial documentation in customary boost formats 2. Enhancing the interface to provide more explicit preload and caching control to include the amount of RAM to reserve, perhaps with the ability to specify posix alignment to maximize benefit of linux anonymous huge page support. 3. Make the library C++ 11 ready 4. Finalize data layout and support for variable length payloads 5. Provide convenient interface for storing std::string (or the contents thereof) in payloads 6. Prepare the library for submission for formal review Any comments and suggestions on this are greatly appreciated. Of particular interest are discussions of technical approaches and estimates of hours required. Please do not send formal proposals. In addition to replying on this list (preferred) I can be reached at the telephone numbers and email below. Comments sent by 21 December will be most valuable. Discussion after that is still very welcome! Please don’t include any proprietary data. Also note that I am not authorized to commit the government in any way--this is simply market research. Thanks! Joel Dr. JOEL D. YOUNG Assistant Professor Computer Science Department Naval Postgraduate School Glasgow East Rm 338 jdyoung(a)nps.edu (831) 656-3518

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Security bugs policy
by Artyom Beilis 22 Dec '12

22 Dec '12

Hello, I would like to know if there is any policy about security bug fixes, updates or releases. What I'm talking about. Consider a security related bug discovered in boost library. For example: For example recently reported bug in Boost.Locale that will be fixed in 1.53 https://svn.boost.org/trac/boost/ticket/7743 I consider it security bug as an application that validates the input (checks if it is UTF-8) may accept an invalid sequence. Or very critical bug in UUID (fixed in 1.43): https://svn.boost.org/trac/boost/ticket/3971 That any application that used them may be target to UUID guessing. These kind of bugs in general should be considered critical and somehow published, it may be also important to backport the fixes to stable releases, because not everybody can move forward and they may need to stick with older releases (as Boost is neither ABI nor API backward compatible even between minor releases). Annoucements of such bugs may be critical for example for stable Linux distributions that ship some older Boost versions and likely need to backport such bug fixes to their own boost tree because Boost doesn't do it. Questions: - Do we have any policy about it? - If not we probably need one including backporting of security bug fixes to stable releases. What brings me to other issues... Should Boost support older releases with critical bug fixes/security bug fixes? For how long time? Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/

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Question about test failures
by Andrey Semashev 22 Dec '12

22 Dec '12

Hi, I've been looking through Boost.Atomic test results [1] and saw that all tests on IBM_Canada_Ltd are marked as failed. The test result [2] refer to Boost.Thread build results [3] which I think is supposed to mean that the test failed because the dependent library failed to build. However, the Boost.Thread build report is marked as succeeded. I'm not sure how to interpret these results. Can someone clarify this? Thank you. [1] http://www.boost.org/development/tests/trunk/developer/atomic.html [2] http://www.boost.org/development/tests/trunk/developer/output/IBM_Canada_Lt… [3] http://www.boost.org/development/tests/trunk/output/IBM_Canada_Ltd-boost-bi…

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[release] add comments/changes
by Oliver Kowalke 21 Dec '12

21 Dec '12

Which files do I've to use in order to add notes about changes and new features of the next release? thx, Oliver

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[Git] Extracting libraries from the svn sandbox
by Beman Dawes 20 Dec '12

20 Dec '12

One of the issues that came up in the documentation discussion was the desire to extract still useful sub-trees from the old svn sandbox, and to move them to GitHub. I've been able to extract my proposed endian library from the sandbox, history and all. Here was the process: 1) Created a empty repository named "endian" in my GitHub account via the usual web interface. 2) From the command line, in a temporary directory: git svn clone https://svn.boost.org/svn/boost/sandbox/endian (Got a "Error validating server certificate...", and gave "p" as a response to the "(R)eject, accept (t)emporarily or accept (p)ermanently?" query. The process ran for perhaps 10 minutes, but that was fine because it was successful at recovering history. And it is a one-time process.) cd endian git branch -d git-svn git push --mirror git@github.com:Beman/endian.git That's it! The git branch command deletes the git-svn branch, which is an artifact of the conversion process. Finish off by cloning the library in its permanent local location: cd permanent-local-location git clone git@github.com:Beman/endian.git Comments? Is there a better way to do this? Once comments have come in, I'll create a doc page for doing this, with a link from the FAQ. --Beman

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[intrusive] boost/intrusive/detail/has_member_function_callable_with.hpp: inheriting from a const class
by Krzysztof Czainski 20 Dec '12

20 Dec '12

Hello, I tried to use a boost::container::vector with a Texas Instruments compiler, and I got an error pointing to line 88 of <boost/intrusive/detail/has_member_function_callable_with.hpp> "Invalid base class", with Type=const std::allocator<something>" Here's the context: template <typename Type> class BOOST_PP_CAT(has_member_function_named_, BOOST_INTRUSIVE_HAS_MEMBER_FUNCTION_CALLABLE_WITH_FUNCNAME) { struct BaseMixin { void BOOST_INTRUSIVE_HAS_MEMBER_FUNCTION_CALLABLE_WITH_FUNCNAME(); }; struct Base : public Type, public BaseMixin { Base(); }; // <-- line 88 The problem seems to be the constness of Type. Here's a simplified example: struct X {}; template < class T > struct Y : T { Y() {} }; int main() { Y<const X> y; } The above example compiles fine with Linux gcc version 4.5.4, and MinGW 4.5.0, but fails with my TI compiler. My question is: is this a bug of the TI compiler, or is that compiler actually right about this, and should we fix this in Boost? For now, my workaround is: struct Base : public ::boost::remove_cv<Type>::type, public BaseMixin { Base(); }; // <-- line 88 Regards, Kris

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