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[tweener] Preliminary Submission
by Julien Jorge 05 Mar '13

05 Mar '13

Hello, I would like to propose the Boost.Tweener library for preliminary submission. The purpose of the Boost.Tweener library is to provide solutions to interpolate the intermediate values between two given values during a time interval. Various easing functions can be applied to control the computation of the intermediate values. I felt the need of such a library while developing games but I have also seen this need in various animation softwares. The library provides the following functionalities: - Interpolation is done on the value of a given variable or using an user-provided callback function, - The interpolated values are computed using a predefined easing function or any user-provided function respecting the contract, - Several tweeners can easily be executed simultaneously or in a row, - The type of the interpolated values are user defined. Please follow this link to download a Zip of the library: http://sourceforge.net/projects/libclaw/files/boost/boost-tweener-rc1.tar.g… Can you check that the library works as expected or tell me what should be fixed before submitting for review? There are various example programs in the archive. Regards, Julien Jorge

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[thread] boost::thread and thread safety annotations
by Wladimir 04 Mar '13

04 Mar '13

Hello, The Clang C++ compiler project is currently working on a thread safety analyzer. By making use of so-called thread safety annotations within the source code, several problems with synchronization primitives can be found statically. For example: usage of a data structure without acquiring its guarding lock. See here for an overview of the available attributes: http://clang.llvm.org/docs/LanguageExtensions.html#threadsafety It is customary to use these attributes by defining macros, for compatibility: http://www.mail-archive.com/linuxkernelnewbies@googlegroups.com/msg01455.ht… At one time, it was also supposed to end up in G++, but this was abandoned in favor of clang (see http://gcc.gnu.org/wiki/ThreadSafetyAnnotation) But at least the annotations are fairly standardized. I think it would be useful to add these annotations to boost::thread, so that projects using that library can make use of the static checking. As I understand it, is only a matter of marking data structures that serve as lock/scoped_lock (such as boost::mutex, boost::recursive_mutex, ...), and methods that act upon the lock with the appropriate attributes. Any interest in this? Regards, Wladimir

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[thread] barrier::wait() not marked as interruption_point
by Oliver Kowalke 04 Mar '13

04 Mar '13

In the documentation (1.53 beta) barrier::wait() is not marked as interruption-point nor that it will throw thread_interrupted if thread blocked inside barrier::wait() if it gets interrupted. Because barrier::wait() calls condition_variable::wait() and condition_variable::wait() is a interruption-point barrier::wait() should it be too - or do I miss something? Oliver

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Re: [boost] [persistent] Library preview: Persistent
by Stefan Strasser 04 Mar '13

04 Mar '13

Am 04.03.2013 16:52, schrieb Jarrad Waterloo: > So if your library is in need, which it is, than release it, preferably > to boost under the boost license. You can always improve, add on latter. > You may solicit architecture and requirements from the list to increase > its usefulness and minimize rewrites. If you can't provide enough > manpower to complete it or even if you can, than solicit help. If four > people throughout the world can get it done in half the time of one > person than WOO HOO! There are many who would like to contribute from > the beginning, which also can't hurt acceptance. The important thing is > to have a vision, preferably shared, and to release something usable, > useful and working, as quickly as possible before interest dries up and > in a timely manner. > > Thanks for your remarks! Specifically for Persistent: > Have you considered an MVCC [option] where there are no updates from a > users perspective but are rather inserts; This sacrifices hard drive > space for a lock free/low lock database. yes, the entire storage backend is based on MVCC [1]. there currently is no lock-based option. objects are MVCC in memory for concurrency (see section "concurrent transactions" [2]), and on disk to achieve atomic updates. when an update is safely synced to disk the old object versions are discarded. I haven't written much about the backend in the documentation for two reasons: the interface is most important, and I actually don't think it would get used much in the long term. as much as I try to make it safe and efficient, a backend using an industrially proven storage engine like BerkeleyDB or SQLite would almost always be preferred, if the stored data has any value. I've written more about this in a previous reply to Klaim-Joël Lamotte in this thread. Would you like to share anything on the architecture of the interface? > Since you in some ways may be competing against relational databases by > making a object oriented database, maybe equivalent administrative > functionality are in order such as import and export into some textual > representations. > On a related note, ways to access system information such external > id/OIDS, timestamps, version numbers via an API for tooling and maybe > querying purposes > ?File format specifications? this and much more is certainly needed for database applications. but since we don't have the resources to implement an industrial-strength storage engine, my approach was to provide one "black-box" implementation for applications that would have used (boost.)serialization or other files otherwise, and provide resource managers using external databases later on. > > Concerning my interest, why haven't you given this to me two years ago, > how much longer must I wait. [Ha Ha Ha] *pointing to the copyright notice* :p Regards, Stefan [1] http://en.wikipedia.org/wiki/Multiversion_concurrency_control [2] https://svn.boost.org/svn/boost/sandbox/persistent/libs/persistent/doc/html…

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Is there interest in a collection of call stack utilities?
by Aurelian Melinte 04 Mar '13

04 Mar '13

Hello, I have a collection of debugging/diagnostic utilities to inspect the run-time call stack and to resolve symbol information. The tools are currently C++11 code and support GNU-Linux and Windows. An overview is available at https://freeshell.de//~amelinte/call_stack_usage.html Is there interest for potential inclusion in boost? Thanks, Aurelian

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[persistent] Library preview: Persistent
by Stefan Strasser 04 Mar '13

04 Mar '13

Hi everyone, I'm thinking about finishing a library that was proposed a couple of years ago. It was pretty far along, and there is documentation available in the sandbox (somewhat outdated): https://svn.boost.org/svn/boost/sandbox/persistent/libs/persistent/doc/html… It is a library with the goal of storing C++ objects on disk, with an interface that is as close as possible to accessing regular C++ objects in memory. A very simple example could look like this: shared_loc<person> p=...; { transaction tx; p->name="..."; p->address="..."; tx.commit(); } It is based on Boost.Serialization, but automatically maintains a consistent state on disk (ACID transactions), which can be updated incrementally. Part of its code was moved to a library named Transact to work alongside other transactional resources (like memory) and is available in the sandbox: https://svn.boost.org/svn/boost/sandbox/transaction/boost/transact/ I'd like to know whether the boost community is still interested in such a library, and I suppose there are quite a few new people here so your comments are welcome as well. Thank You!

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[thread] why is 'thread_group' in 'boost/thread/detail'?
by pavel 03 Mar '13

03 Mar '13

as of 1.53 the docs say the 'thread_group' class is included by this instruction: #include <boost/thread/thread_group.hpp> http://www.boost.org/doc/libs/1_53_0/doc/html/thread/thread_management.html… whereas the actual file is not in the 'boost/thread', but accidentally is in 'boost/thread/detail' is that intentional? -- Pavel P.S. if you notice a grammar mistake or weird phrasing in my message please point it out

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Copyright notice update policy
by Mateusz Loskot 03 Mar '13

03 Mar '13

Hi, What is the policy of updating year in copyright notices? There are several pages ([1], [2], [3]) where copyright notice is explained, but without any notes on the year detail I found one thread [4] about copyright policy, but it discusses only copyrighting patches and fixes. I understand it may depend on local law in particular country, (i.e. it seems U.S. requires year [5]). However, without digging law backgrounds, I'd simply like to know what is Boost policy for the notice updates. For example, a file created in 2009 includes relevant copyright notice and in 2013 the file receives update. Is it required to update the copyright year to 2009-2013? [1] http://www.boost.org/users/license.html [2] http://www.boost.org/users/faq.html [3] http://www.boost.org/users/index.html [4] http://lists.boost.org/Archives/boost/2012/01/189315.php [5] http://www.contentious.com/2007/01/07/copyright-notice-is-the-year-really-n… Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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[exception][locale][timer] Pre-built library list in getting started guide.
by Daniel James 03 Mar '13

03 Mar '13

According to this ticket, building details are missing from the getting started guide: https://svn.boost.org/trac/boost/ticket/7324 Exception, locale and timer either need to be built, or have optional parts that need to be built. Please can appropriate people comment (in the ticket, not here) on what the libraries' need, so that I can fill in missing entries. If details are needed please write some text that I can copy and paste into the document, since you should be able to do a better job of writing it than I could. thanks, Daniel

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variant with shrink
by Niitsuma Hirotaka 03 Mar '13

03 Mar '13

boost::variant should be variant<int,int> => int variant<int,double> => double variant<int,boost::rational<int> > => boost::rational<int> variant<int,double,std::string> => variant<double,std::string> I wrote such extension https://github.com/niitsuma/variant_shrink Default generalize order is int < boost::rational<int> < float < double < std::complex<double> You can use other custom generalize relation by defining function object is_generalizable_to<Type,TypeTo>

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