August 2013 - Boost - lists.preview.boost.org

How not to use auto-link?
by Daryle Walker 23 Aug '13

23 Aug '13

Recently, I've been using CodeLite for Windows to do my Boost work. I have it running a MinGW-builds version of GCC 4.8 by default. I've enabled CodeLite to use Visual C++, since I have a copy of the Express version and want to avoid missing MSVC-related errors in the future. After telling CodeLite where MSVC and its directories are, I ran "rational_test.cpp" by itself, which gave up a linking error for Boost.Test. The linker was looking for those fancy named libraries that I didn't automatically make since I usually include all the source files. (And I'm using Boost from a Subversion download instead of a fixed one.) I added the source files from Boost.Test and #defined BOOST_ALL_NO_LIB=1 from the project options. The project-make system was still looking for library files! (I don't recall if it was asking for the same library file.) As I already built those files while experimenting with the documentation system, I added that directory to the search list and everything worked. I thought defining BOOST_ALL_NO_LIB was sufficient to disable auto-linking. What did I mess up? Daryle W.

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[rational] Which way should std::numeric_limits::min go?
by Daryle Walker 23 Aug '13

23 Aug '13

The default implementation of a std::numeric_limits<T> instantiation is to have all static data member be set to static_cast<X>(0) and all the static member functions return T{}. When an instantiation is manually written, you're supposed to leave members for the types of numbers (integer vs. floating vs...) that you're NOT as in the unimplemented case. The static member function "min" has a defect. The function "denorm_min" returns the smallest positive value that can be represented (denormalized or not), and is implemented only for floating types. The function "lowest," new to C++11, returns the regular (i.e. not Infinity or NaN, etc.) value closest to negative-infinity. Lowest was introduced because for C++98/03, "min" returned "denorm_min" for the built-in floating types and "lowest" for built-in integer types! You can't get generic code out of that (without checking some more flags from numeric_limits). Which version of "min" should boost::rational take? I was think of "denorm_min," since I'll be implementing that. The built-in integer types use "lowest" for "min," but don't define the other one at all. Daryle W.

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concurrent_unordered_map request
by Eugene Gordienko 23 Aug '13

23 Aug '13

TBB and Microsoft have it. Why not to have it in boos?

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Reboot the boost web server machine
by DongInn Kim 22 Aug '13

22 Aug '13

Dear Boost community, There is a system upgrade on the boost web server machine and we need to reboot the machine to activate this change. Can we setup a schedule to reboot the server machine (wowbagger.crest.iu.edu) sometime this week? It would not take long to reboot the system (e.g., less than 10mins). If it does not cause too much disturbance, can we reboot the system at 9am tomorrow (Aug 22, 2013)? Regards, -- - DongInn

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[rational] Updated for fix; run tests
by Daryle Walker 22 Aug '13

22 Aug '13

Earlier today, I uploaded a fix a narrowing-conversion bug to boost::rational. (Ticket #5855, change-set [85418]) But I did another check-in first (change-set [85417]). The lower-numbered change represented a problem while fixing the ticket. C++11 adds two static members to std::numeric_limits. One of them, max_digits10, represents how many digits are needed to be printed to (near) guarantee text/binary conversion. Boost.Test uses it in its C++11 code, so it expects any version of numeric_limits to have it, which caused errors with Boost.Rational since that part of the test code hasn't been touched since it was written nearly 7 years ago! (There was a minor tweak over 5 years ago.) One advantage with Git is that I could have checked both changes separately. Here, for Subversion, I had to back out the second change, commit the first, then redo the second to get them recorded independently. I just did a quick look at our regression tests, and most of them involve one or both of the issues I just fixed. So can everyone do a test cycle sooner rather than later? (The "teeks99-08(e|f|g|h)-Ubnutu12.04-64" teams need to make sure Clang is installed and in the PATH.) Daryle W.

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[countertree] Concurrent set and map with random access iterators
by Francisco José Tapia 21 Aug '13

21 Aug '13

Hi this message is to announce the version 2.0 of the [countertree + suballocator] library. *This library provide a **concurrent** and **thread safe** implementation of the tree based data structures (**set, multiset, map** and **multimap**, plus a new data structure named **vector_tree**) with **random access iterators** and **access by position** like a vector. * *This permit to distribute the elements stored in the trees, between an arbitrary number of threads, identically as do with the vectors, making easy the design of **parallel algorithms** applied to the tree based data structures (as you can see in 2.3.- Examples<https://dl.dropboxusercontent.com/u/8437476/works/countertree_2.0/doc/P2.3_…>and 3.6.- Examples<https://dl.dropboxusercontent.com/u/8437476/works/countertree_2.0/doc/P3.6_…>) , and their use by the **multicore development tools** as **OpenMP, Threading Building Blocks ...* *You can find the documentation and the code in the GitHub* *https://github.com/fjtapia/countertree_2.0*<https://github.com/fjtapia/countertree_2.0> or you can see online in my dropbox page : https://dl.dropboxusercontent.com/u/8437476/works/countertree_2.0/index.html<https://dl.dropboxusercontent.com/u/8437476/works/countertree_2.0/doc/index…> If you prefer download a file with all the code and the documentation : https://github.com/fjtapia/countertree_2.0/blob/master/doc/countertree_2.0.… Perhaps the most interested parts of the documentation are : 1.4.- Concurrent version where explain the problems and new functions implemented 1.5.- Next improvements. Where explain the future development of the library and the concurrent algorithms 1 year ago I presented the request for the evaluation of the [countertree+ suballocator] version 1.0. The approval process is stopped due to the absence of review managers, and in the meanwhile I continued with the develop of this version 2.0. This version is big ( 50.000 lines ) and involve many programming areas ( algorithms, memory management, threads, locks ...) In the design process I must took many decision according my knowledge. I am sure there are many things to correct and improve. In the Boost community there are many people with knowledge and experience, and I trust they can help me in order to provide to the C++ users a good library. If you find an error, or you miss something in the library or have any idea or comment about it, please mail me and I will correct as soon as possible. Sincerely yours Francisco Tapia fjtapia(a)gmail.com *The Boost Formal Review Schedule is in http://www.boost.org/community/review_schedule.html where you can see the projects and their situation.

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Re: [boost] Request to allow contribution to Boost.Multiprecision cpp_bin_float
by Jyotesh Choudhari 20 Aug '13

20 Aug '13

Thanks for your replies. >>> I would like to contribute to the development of Boost.Multiprecision >>> cpp_bin_float library. Can I work on it? If yes, then how can I start? >> Hi Jyotesh, >> Paul Bristow, Chris Kormanyos and I have been discussing this off-list. >> There is a prototype implementation in the sandbox under the >> multiprecision.cpp_bin_float directory.? The current code is pretty much >> complete, but under-tested.? The binary-decimal and decimal-binary >> conversion routines used are also brain-dead and do not round correctly (I >> have a mostly working version that does this correctly on my hard drive, but >> it's not quite ready for commit yet). > Yes. But remember, Jyotesh, John has taken a different direction > than my original code in the sandbox. His implementation is in > a different directory, and it's likely that we will stick with John's > and leave my prototyping to rest. May I know which directory is this? >> So one of the things we need is for >> folks to try this out and see what breaks (or rather to see what they can >> break!). > Such as try some simple math functions or to use it in > conjunction with boost::math::constants for, say, computing > a few hundred digits of pi or log(2). OK. I will try these. >> Some of the std lib function test cases in the sandbox also fail >> currently as their error rates are too high.? Many are also much slower than >> say MPFR.? Chris, would have a better idea which most need working on. > Always important are square root, sine, cosine, and log. >> And finally, the implementation uses all integral arithmetic internally (via >> cpp_int), so one big improvement we need is for someone to write Karatsuba >> and FFT based multiplication routines for cpp_int (Karatsuba is probably the >> higher priority).? Oh and we have no docs yet. > Yes, very important, as this is a huge limitation of cpp_dec_float --- > at least for the digit hunters among us. :-) I will implement Karatsuba algorithm and let you know when I am finished. Thanks and Regards, Jyotesh Choudhari >> Anything there look like something you'd like to work on? >> Thanks for the interest, John. > Thanks for the interest. > Sincerely, Chris.

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Is there BOOST_ENABLE_IF macro now?
by TONGARI J 20 Aug '13

20 Aug '13

Hi folks, It's over 2 years since this post: http://boost.2283326.n4.nabble.com/New-powerful-way-to-use-enable-if-in-C-0… The macro looks sweet and I wonder if we have this macro in Boost in case that I missed it. Thanks.

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Re: [boost] [boost::spirit::basic_hold_any] needs non template operator=
by Hartmut Kaiser 20 Aug '13

20 Aug '13

> I found that hold_any template operator= is not used during assignment to > another hold_any (as intended by its developer). Instead compiler uses > self generated version of operator= which doesn't forward to assign(const > basic_hold_any&). This leads to memory corruption. > The fix is simple - you need to add explicit operator=(const > basic_hold_any&). > My compiler is gcc 4.4.7 and I use option -std=c++0x Version of boost is > 1.53 but I don't see that something changed in 1.54 so it should have the > same issue. Please provide a patch which I will gladly apply. Regards Hartmut --------------- http://boost-spirit.com http://stellar.cct.lsu.edu

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[thread] Dividing into Boost.Thread and Boost.Sync
by Andrey Semashev 20 Aug '13

20 Aug '13

Hi, In our private conversation Vicente J. Botet Escriba, Tim Blechmann and myself have formed a proposal to split the current Boost.Thread library into two libraries: Boost.Thread and Boost.Sync. The former will retain its thread management features, such as thread class, futures and TLS. The latter will contain all thread synchronization components, such as: - locks - mutexes - condition variables - call_once Mutexes and condition variables in Boost.Sync will not support thread interruption and will be as simple and lightweight as possible. For example, one of the benefits I'd like to achieve with this is that synchronization primitives should become decoupled from the timing libraries. I'm not sure we'll be able to make the whole library header-only, but we will try to. If some component is header-only, it will not require linking to Boost.Sync. We plan to add new components to Boost.Sync after the extraction is made. The current candidates for addition are: - spin_mutex and yield_spin_mutex. There are several implementations in Boost, namely in Boost.SmartPtr, Boost.Log and Boost.Atomic. The plan is to refine them into two flavors of spin mutex and move to Boost.Sync and then switch these libraries to the common implementation, if possible. - once blocks from Boost.Log. - portable Windows-style events. There is a prototype implementation in Boost.Log. Boost.Thread will depend on Boost.Sync and will retain headers and possible glue code for backward compatibility. For instance, I think it will have to implement interruptible condition variable. Comments are welcome.

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