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numeric_cast
by Brandon Kohn 03 Aug '11

03 Aug '11

Hello, Recently I was creating a new numeric type which I wanted to use along with boost::numeric_cast. I read over the docs and examples and found that it seemed to support (at least partially) the notion of policy driven casting operations. I was unable to figure out how one might use a custom conversion or overflow policy along with the actual boost::numeric_cast<N>(x) function. In the end I created a workaround which seemed to work nicely: template <typename ConversionTraits, typename EnableIf = void> struct numeric_cast_traits { typedef def_overflow_handler overflow_handler; typedef UseInternalRangeChecker range_checker; typedef Trunc < typename ConversionTraits::source_type > rounding_policy; }; template <typename Target, typename Source> inline Target numeric_cast( Source arg ) { typedef boost::numeric::conversion_traits<Target, Source> conv_traits; typedef numeric_cast_traits< conv_traits > cast_traits; typedef boost::numeric::converter < Target , Source , conv_traits , typename cast_traits::overflow_handler , typename cast_traits::rounding_policy , boost::numeric::raw_converter< conv_traits > , typename cast_traits::range_checker > converter; return converter()(arg); } This change allowed me to easily customize the numeric_cast function for individual conversion types. Did I miss something in the official library? If not, would this change be something good to go in? Regards, Brandon Kohn

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[log] how to set attributes under multi-threaded application
by Jinqiang Zhang 03 Aug '11

03 Aug '11

In boost::log documentation, there's some code as following: * typedef attrs::mutable_constant< int > int_constant_t; boost::shared_ptr< int_constant_t > attr(new int_constant_t(-5)); lg.add_attribute("MyInteger", attr); BOOST_LOG(lg) << "This record has MyInteger == -5"; **// Change the attribute value attr->set_value(100); BOOST_LOG(lg) << "This record has MyInteger == 100"; * Now I have a situation in my multi-threading app: the 'attr->set_value()' could be called in different threads, so the following 'BOOST_LOG(lg)...' could access wrong attributes that is set by another thread. If I use a mutex to protect this, it would be stupid, because the log line might be filtered out, that means the 'locking mutex' is not neccessary. Who can help ? Jinqiang *btw, the boost::log documentation isn't too good, when I read it, I felt I lost in a juggle.*

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Move on Sandia intel
by Ion Gaztañaga 03 Aug '11

03 Aug '11

Hi, A test is failing for Move in Sandia-darwin-intel-11.1 (and 12.0): http://www.boost.org/development/tests/release/developer/output/Sandia-darw… and I don't know why, since Intel 11.0 in windows seems to work fine. Anyone with access to that compiler can help me? Thanks! Ion

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Boost.Process progress
by Boris Schaeling 03 Aug '11

03 Aug '11

There haven't been much news on Boost.Process lately which doesn't mean though that nothing is happening. I've been working on a Boost.Asio extension which can be used to wait asynchronously for Windows processes - see https://github.com/BorisSchaeling/asio. This was already supported by Boost.Process 0.4 but the implementation was heavily criticized. The code has been moved now to Boost.Asio (or at least I hope it will - I'm in contact with Chris :) and provides a new Windows I/O object called object_handle. The implementation is now based on the Windows function RegisterWaitForSingleObject(). The new I/O object can not only be used to wait for processes. It can also be used to wait for events, mutexes, semaphores etc. As it's not process-related anymore, it makes sense to ship the code with Boost.Asio (where we have already similar Windows I/O objects called random_access_handle and stream_handle - object_handle fits in nicely). Once I'm done with this, a major critical point should have been resolved. I'll go back then to Boost.Process code and help Jeff to finish https://github.com/JeffFlinn/boost-process. I'm not sure how far we are there. But as I don't remember any major obstacles, I'm confident that there are none. :) Boris

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[TTI] Review Result
by Joel falcou 02 Aug '11

02 Aug '11

This is the result summary for the Type Traits Introspection library by Edward Diener. The review have been on going from July 1st to july 17th and had generated a large amount of very interesting design discussion. The library received 5 Positive reviews and a few positive comments next to that. **The verdict is that, the TTI Library is ACCEPTED into Boost.** However, a few comments and concerns have been raised but are rather simple changes to perform and I am sure Edward will take these comments into account before releasing the library. Such comments include: * The main comment is the fact that Boost.TTI force the definitions of its meta-functions into the boost::tti. Concerns have been raised and requests made that the macro don't specify any namespace and let users bring the generated meta-functions in the namespace of their own liking. * The number of macros handling various corner cases has been raised as potentially too high. Effort to streamline the macro based interface has been requested. * Support for more compiler is needed. Some issues on ICC has been raised but are currently being looked upon (or fixed). * Naming scheme of the macro and of the generated meta-functions have to be refined to be 1/ more clear 2/ avoid some non-standard name starting with __ * Some more detailed and entry-level examples may be beneficial to the library * Pre-made macro for classical typedef like value_type or other std components has been proposed Thanks to all the participants and to Edward for this review.

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[Boost] [GSoC] [Checks] Issue with the design
by Pierre Talbot 02 Aug '11

02 Aug '11

Hello everyone. We talked a few days ago about the design of the check library (about the compile or run-time weight parameter.) Reminder : the weights are the contribution to the running sum of a digit in a number. I used and followed your ideas and suggestions that bring me to the policies class. I tried to extract the characteristics of a "generic" check and the weight is one of these. So I tried to implement the weight policy class : #define _WEIGHT_factory(z,n,unused) \ template<BOOST_PP_ENUM_PARAMS(n, int weight)> \ struct weight_policy \ { typedef typename boost::mpl::vector_c<int BOOST_PP_COMMA_IF(n) BOOST_PP_ENUM_PARAMS(n, weight)> weight ; } ; \ BOOST_PP_REPEAT_FROM_TO(1,BOOST_CHECK_LIMIT_WEIGHTS,_WEIGHT_factory,~) #undef _WEIGHT_factory But the compiler doesn't like the "struct template parameter overloading". Is a limit of the language ? Or am I doing it in the wrong way ? If it's impossible, I though that we could passed the weights to a function that aimed to "build" the vector_c type. While we speak about the design, what do you think about the policies class ? There are useful because the core of the algorithm is the same for every checks. Every critics or suggestions are welcomed, thank you, Pierre Talbot.

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GSoC Doc Camp
by Boris Schaeling 01 Aug '11

01 Aug '11

Google sent an email to the GSoC mentors list to invite to a GSoC Doc Camp - see https://sites.google.com/site/docsprintsummit/. It's five days in October just before the GSoC Mentor Summit starts. Those wishing to attend do not need to be from a GSoC project. As the application deadline is this Friday, hurry up if you are interested. Boris

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Article on Boost.Asio in German computer magazine c't
by Boris Schaeling 01 Aug '11

01 Aug '11

I submitted today an article on Boost.Asio which will be published in the German computer magazine c't. I don't know yet in which edition but will tell on http://www.highscore.de/feed.atom. There may be more articles on Boost in c't in the future which I'll announce on my RSS feed then only (not to spam these lists). All of this hopefully helps to increase media coverage of Boost in the longterm. This again could help if for example BoostCon grows into something bigger. For now the article on Boost.Asio is a small step-stone. :) Boris

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Book "The Boost C++ Libraries" available at Amazon, Barnes and Noble and others
by Boris Schaeling 01 Aug '11

01 Aug '11

A new edition of my book "The Boost C++ Libraries" has been published. It's not (yet) online at http://en.highscore.de/cpp/boost/ as some may expect. Instead it is available at Amazon, Barnes and Noble and others as a print book. What's new: * Several chapters were updated (to Boost.Spirit 2.x, Boost.Signals 2, Boost.Filesystem 3...) * Many new libraries are covered (Boost.CircularBuffer, Boost.Intrusive, Boost.MultiArray...) * The book has now an index (12 pages with class/function/object names used in the book) * The English has been greatly improved :) The book is based on Boost 1.47.0. It covers 38 libraries which I would describe as general purpose libraries (no libraries like Boost.Quaternions for example). It's based on C++98 and ignores C++0x (in a new edition of the book, I can for example probably drop Boost.Lambda). It has 262 pages and about as many examples. Every example is complete - it can be built and run as is (helpful if my explanations are not good enough and you want to see what an example really does :). One should be able to read the book in one or two days and know then what those 38 libraries do, when to use them and how to use them. To keep this email short - please see http://xmlpress.net/publications/boost for more information. If you read the book and have any comments or questions - please tell me! The book was written by someone part of this community, so I'm interested in what the community thinks. I also hope that I could paint a picture of the community everyone can identify with. I got a lot of feedback on my online book in the past and try to improve the book accordingly. So drop me a line if you like! Boris

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what happened to context mini-review?
by Nathan Ridge 01 Aug '11

01 Aug '11

Hello, Up until a few days ago, the Review Schedule contained an entry for the mini-review of the Context library (which has previously been accepted provisionally) starting from July 28. Now the entry is gone and there is no sign of a mini-review on the list. What is the status of the library? Has the mini-review been postponed? Or will the library be accepted without a mini-review? Thanks, Nate

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