May 2011 - Boost - lists.preview.boost.org

BoostCon video mirror
by Jeroen Habraken 23 May '11

23 May '11

Hi, After becoming annoyed with blip.tv I've created a mirror of the BoostCon videos with the help of Nikhef (http://www.nikhef.nl/en/) It can be found at http://wipkip.nikhef.nl/events/BoostCon/2010/ and there's a quick overview over at http://vexocide.org/boostcon.html. If desired we'll gladly host the 2011 videos as well. Regards, Jeroen Habraken

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[process] boostcon code now on github
by Jeff Flinn 22 May '11

22 May '11

The source code as presented at the boostcon "Boost Process" session is now available at: https://github.com/JeffFlinn/boost-process Let me know if there are any problems accessing this as I'm a github newbie. Thanks, Jeff

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[btree] Status report
by Beman Dawes 22 May '11

22 May '11

The slides for my BoostCon "Proposed Boost B-tree Library" presentation are available: http://github.com/boostcon/2011_presentations/raw/master/tue/proposed_b_tre… Please be aware that while the library is progressing nicely, it isn't ready for production use: * There are outstanding bugs, particularly with variable length data. * Names and signatures may still change. * Documentation is barely started. * Build is failing on Mac OS X. That probably won't get fixed until after BoostCon. (Reported by Marshall Clow) That said, the response to the presentation was very positive and I'm actively continuing development. Anyone interested in the library is encouraged to take a look and give it a try. See http://github.com/Beman/Boost-Btree/blob/master/README for install instructions. Feedback welcome! Thanks, --Beman

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Invitation to connect on LinkedIn
by Илья Биин via LinkedIn 21 May '11

21 May '11

LinkedIn ------------Илья Биин requested to add you as a connection on LinkedIn: ------------------------------------------ Yuriy, I'd like to add you to my professional network on LinkedIn. - Илья Accept invitation from Илья Биин http://www.linkedin.com/e/bv6hcz-gnyytzl3-3y/uV9CsZkavY-uKU5A7C-1JbkavY-u5P… View invitation from Илья Биин http://www.linkedin.com/e/bv6hcz-gnyytzl3-3y/uV9CsZkavY-uKU5A7C-1JbkavY-u5P… ------------------------------------------ DID YOU KNOW that LinkedIn can find the answers to your most difficult questions? Post those vexing questions on LinkedIn Answers to tap into the knowledge of the world's foremost business experts: http://www.linkedin.com/e/bv6hcz-gnyytzl3-3y/ask/inv-23/ -- (c) 2011, LinkedIn Corporation

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Invitation to connect on LinkedIn
by Serge Blazhievsky 21 May '11

21 May '11

LinkedIn ------------ I'd like to add you to my professional network on LinkedIn. - Serge Serge Blazhievsky Staff Software Engineer at LiveOps San Francisco Bay Area Confirm that you know Serge Blazhievsky https://www.linkedin.com/e/bv6hcz-gny8eb0s-6p/isd/2953122588/yo_3A_ww/ -- (c) 2011, LinkedIn Corporation

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Boost statechart viewer
by Petr Šilhavík 20 May '11

20 May '11

Dear Boost-Statechart developers and users, I would like to ask you to try the tool that I am developing in my bachelor thesis and give me your opinion about it. The tool is able to visualize state machines that use Boost-Statechart library. It uses Clang and LLVM *(version 2.9)* for producing the output files that can be visualized using dot. Now it can work with states (not the orthogonal states), transitions and custom reactions. You can find more information about it on the web page of this project where you can also download the source codes and see some examples of the output pictures. http://rtime.felk.cvut.cz/statechart-viewer/ I am looking forward to your answers. Best regards Petr Silhavik

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[Unicode] Library info
by Mathias Gaunard 20 May '11

20 May '11

Just a remainder for people that followed my Unicode presentation at Boostcon: Library is available on the Boost Sandbox: <https://svn.boost.org/svn/boost/sandbox/SOC/2009/unicode> Documentation is available here: <http://mathias.gaunard.com/unicode/doc/html/>

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How to inspect state of boost::mt19937?
by Matthew Gwynne 20 May '11

20 May '11

Hi, Does anyone know how I can access the internal state of the Mersenne twister (boost::mt19937) easily? That is the 623 state bytes. I am looking to initialise a random number generator and then inspect the state to compare it to another system which apparently implements MT19937 but gives different results. If someone could point me in the right direction, that would be great! Thanks! Matthew Gwynne http://cs.swan.ac.uk/~csmg/

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Generic try, catch in boost::lexical_cast
by Jeroen Habraken 20 May '11

20 May '11

Hi, Whilst updating SVN today I spotted a change to boost::lexical_cast, https://svn.boost.org/trac/boost/changeset/71958, which introduces a try { } catch(...) { } construction. I'm curious as to why this catch-all is needed since it seems to be there to deal with boost::numeric_cast exceptions and whether it could lead to a std::bad_alloc being rethrown as a bad_lexical_cast. Kind regards, Jeroen Habraken

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[local] this_ or _this?
by Lorenzo Caminiti 19 May '11

19 May '11

Hello all, Boost.Local uses a special name `this_` to access the object `this` bound from the enclosing scope. Shall this name be `this_` or `_this` according to Boost practices? struct c { void g(int x) { ... } void f() { void BOOST_LOCAL_FUNCTION_PARAMS( (int x) (bind this) ) { this_->g(x); // <<<<<<<<< Shall this be `_this->g(x);` instead? ... } BOOST_LOCAL_FUNCTIO_NAME(l) ... } ... }; In particular, some library uses _ postfix for statements like mpl::if_ (not mpl::_if) while other uses _ prefix for variables like phoenix::local_names::_f (not local_names::f_). Thanks a lot. -- Lorenzo

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Forum created for IDL to C++0x work
by Johnny Willemsen 19 May '11

19 May '11

Hi, Last year I posted on the boost list about ideas for a new IDL to C++0x language binding for CORBA/CCM/DDS. The OMG has issued a RFP for this (see www.omg.org) In order to share technical ideas, we have opened a forum on http://www.orbzone.org, the community portal for Corba, CCM, and related middleware technologies. If you have any ideas, please share them on ORBzone. Regards, Johnny Willemsen Remedy IT

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anonymous svn checkout
by Mathieu Champlon 19 May '11

19 May '11

Hi, http://svn.boost.org/svn/boost seems to be asking for credentials, is it on purpose ? Thanks, MAT.

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Fwd: [ICL] some improvement proposals
by Denis 19 May '11

19 May '11

Hi 1. (questionable because it changes the visible interface): rename `left_open` and `right_open` to `right_closed` and `left_closed`. Reason: interval_bounds is used in bitwise operations with bit=1 means `closed`. `left_closed() | open()` resulting in `left_closed()` is more readable than `right_open() | open()` resulting in `left_closed()`. Also, there are checkers `is_left_closed()` and `is_right_closed()` but not for *_open I had to use `class bounded_value` in my program (as in Icl details: calculating lower and upper bound of interval separately, then constructing the interval, bitwise or'ing bounds) and I commented every usage of `right_open()` as `left closed` in order to explain why I use `interval_bounds::*right*_open()` in constructing the *left `*bounded_value` of the interval. This resulted in the idea of renaming. Maybe making bit=1 mean `open` would be less painful for other users ? 2. define `contains(interval, elt)` as `!below(interval, elt) && !above(interval, elt)` allowing the user to use `below()` and `above()`. Sometimes it is useful. Anyway, all the versions of `contains()` are made of checking for both bounds. 3. It would nice if the functions taking two intervals will have versions taking an element as second argument. I mean functions like `left_subtract`, `operator &`, etc. (I cannot tell all the list at the moment) Constructing temporary `close_interval` object in order only to pass it into those functions is cheap with ints but would be expensive with heap-allocated domains (blobs, strings, etc).

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[iostreams] OK to patch Mac OS X config problem?
by Beman Dawes 19 May '11

19 May '11

The following path fixes a problem that causes a B-tree compile failure on Mac OS X. Does anyone know any reason not to apply this? --Beman PS: Thanks to Marshall Clow for testing this. --- C:\Users\Beman\AppData\Local\Temp\rtl.hpp-revBASE.svn000.tmp.hpp 2011-05-18 22:23:07.000000000 -0400 +++ C:\boost\trunk\boost\iostreams\detail\config\rtl.hpp 2011-05-18 22:21:21.000000000 -0400 @@ -42,13 +42,13 @@ # define BOOST_IOSTREAMS_FD_OFFSET __int64 # else // Borland, Metrowerks, ... # define BOOST_IOSTREAMS_FD_SEEK lseek # define BOOST_IOSTREAMS_FD_OFFSET long # endif #else // Non-windows -# if defined(_LARGEFILE64_SOURCE) && \ +# if defined(_LARGEFILE64_SOURCE) && !defined(__APPLE__) && \ (!defined(_FILE_OFFSET_BITS) || _FILE_OFFSET_BITS != 64) || \ defined(_AIX) && !defined(_LARGE_FILES) || \ defined(BOOST_IOSTREAMS_HAS_LARGE_FILE_EXTENSIONS) /**/ /* Systems with transitional extensions for large file support */

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[boostcon][proto] Suggestion for LIAW session: fixed-point numbers
by Ravi 19 May '11

19 May '11

Hi, Are there any proto-based ideas for the library-in-a-week sessions? If not, would building a fixed-point data type be of interest? The domain is narrow enough that something useful can be accomplished in 4 sessions, but of large enough scope to present opportunities for exploring proto in depth. A fairly simple design follows representing a number: fixed_number<int width, int ulp, // 2^{ulp} is the smallest increment possible bool signed, template assigner<first, last, signed> > 'assigner' handles rounding/truncation/wrapping/etc when assigning another number (floating-point or fixed-point) to the current one. Internally, each fixed-point number would be represented by a boost::uint64_t or a boost::int64_t (limiting the maximum precision allowed). As an example, fixed_number<5, -3, false> would represent a data type that would go from 0 to 3.875 in steps of 0.125. Proto would be used for creating all arithmetic operations since the return type of a+b could be different from the type of either a or b. A bonus would involve getting the fixed-point data type to play well with std::complex (and, yes, I am aware that std::complex is not designed to work with anything other than double and float, and will require specialization in the std namespace). If there is sufficient interest, I could even provide a starting point with +,-,* implemented; / would take more time. The design above is intended as a starting point for discussion and I am most definitely not wedded to it. I am a tyro when it comes to proto, and hence would need someone with more proto expertise to guide the discussion. Regards, Ravi

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[mutex] move / merge
by Phil Bouchard 18 May '11

18 May '11

Hi, Although Block Pointer is now thread safe it could use some optimization. To do so it'll need some special operations on mutexes such as move and merge. The operations need to be atomic as well. I was wondering if this was already attempted. Thanks, -Phil

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Bug #3831
by Chris Wilson 18 May '11

18 May '11

Hi there, I'm attempting to use the JSON parser to read in a JSON file, but I am running up against the problem described in bug #3831<https://svn.boost.org/trac/boost/ticket/3831>, even though this bug has been marked as fixed. The milestone on the ticket is marked as 'Boost 1.42.0', but is has a score through it and I'm not sure if that means it's been fixed in that milestone or if it's been retargeted at a different milestone. I am using version 1.42.0-4ubuntu2 of the libraries so I am wondering if I have an outdated installation, or if there's another reason why I don't have the patched version. Can anyone shed some light this please? Thanks, Chris

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[range] strange behavior of operator== with iterator_range
by Bryce Lelbach 18 May '11

18 May '11

Can someone tell me if the behavior demonstrated in the following program is intentional or a bug in Boost.Range? -- Bryce Lelbach aka wash boost-spirit.com px.cct.lsu.edu github.com/lll-project

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[chrono] Thread clock compatibility problems on Android
by Libor Bus 18 May '11

18 May '11

Hello, has anybody experienced also compatibility problems of chrono library on Android? I found following (Android 2.2, NDK-r5b, chrono v0.71, rev #71693): 1) Sources with boost::chrono::thread_clock does not compile, since _POSIX_THREAD_CPUTIME is not defined on Android. My workaround is to hack chrono/config.hpp: # if 1 //defined(_POSIX_THREAD_CPUTIME) # define BOOST_CHRONO_HAS_THREAD_CLOCK # define BOOST_CHRONO_THREAD_CLOCK_IS_MONOTONIC true # endif 2) ::clock_gettime() fails when called with clock ID got from pthread_getcpuclockid. My workaround is to call ::clock_gettime( CLOCK_THREAD_CPUTIME_ID, &ts ) in chrono/detail/inlined/posix/thread_clock.hpp. 3) Additionally there is precision problem on Linux platforms, stopwatch<process_cpu_clock> provides results with different units on Windows (nanoseconds) and Linux platforms (miliseconds). BR, Libor -- View this message in context: http://boost.2283326.n4.nabble.com/chrono-Thread-clock-compatibility-proble… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Re: [boost] Help on 2 key search
by Vicente Botet 18 May '11

18 May '11

Renee wrote: > > HiAll > Being a newbie i request your help. > > I have a emp database. I store them based on emp id as well as ssn and > need to store their extended details. What datatype is best used to store > this info. I need to search through millions of emp recs that can be > searched by either ssn or by emp id. do suggest. > some fields are as below: > emp id > ssn > emp first name > emp last name > emp sal > emp age > if we use map can have just one key value so it can be either ssn or emp > id. using 2 maps one for ssn and emp record and another for emp id and emp > record is not efficient as there are millions of records. > ur help is appreciated. will multi index help in this case. do suggest. > > -Renee > Hi, If you need to realize search based on these two fields MultiIndex seems the appropriated structure. If emp_id is an integer (unique) the use of a non-ordered index could give you better performances. The major problem is how to ensure this id is unique. I guess that ssn stands for Social Security Number, which is too big to fall on a builtin, so a string will be need. Again the use of a good hash could improve the performances. HTH, Vicente P.S. This kind of questions are better answered on the Boost User ML or even on Stack Overflow. -- View this message in context: http://boost.2283326.n4.nabble.com/Help-on-2-key-search-tp3530830p3531660.h… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[variant] static_visitor deadlock
by Andrew Hundt 17 May '11

17 May '11

I believe I may have found a way to create a deadlock in static_visitor, but it may be my own mistake. It seems if I apply one static visitor within another with an extra call to operator() that I use for shared_ptr objects, the program deadlocks in apply_visitor_binary_invoke::internal_visit(). The template in my class below is another static visitor object, so in essence I am creating an effect similar to a java decorator using visitors. Here is a stripped down version of the class with which the deadlock occurs: /** * @class VisitorDecorator * * @brief decorates (wraps) a normal visitor */ template <typename T> class VisitorDecorator : public boost::static_visitor<typename T::result_type> { typedef typename T::result_type t_result_type; public: VisitorDecorator(boost::shared_ptr<T> deviceCommandVisitor, std::string filename): m_visitor(deviceCommandVisitor), m_filename(filename) {} /** * @brief strip shared pointers and handle the object itself */ template <typename U, typename V> inline t_result_type operator()( boost::shared_ptr<U>& deviceP, boost::shared_ptr<V>& commandP){ return operator()(*deviceP,*commandP); } /** * @brief Connect the specified struct types to the log file */ template<typename U, typename V> t_result_type operator()(U& device, V& command){ return (*m_visitor)(device,command); } private: boost::shared_ptr<T> m_visitor; std::string m_filename; }; Does anyone have thoughts or suggestions, be it my fault or a bug in the library? Cheers! Andrew Hundt

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[introductions]
by Gregory Crosswhite 17 May '11

17 May '11

Hey everyone! I don't know what the protocol is for this, but since I have been posting occasionally for a while and have offered to be a Review Manager but am relatively unknown to the community (which, again, means that I will completely understand and won't be offended in the slightest if you politely decline my offer to be a Review Manager :-) ) and have never introduced myself I figured that now might be as good a time as any: I am a graduate student who will be finishing up my PhD in Physics in the next month. My field is roughly quantum computing/quantum simulation, and my specialty is writing software that solves problems in the field of quantum error correction. My web page, which gives an overview of my background, is here: http://students.washington.edu/gcross/index.html Cheers, Greg

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[multi_index] Extending multi_index_container hash tables
by Vladimir Voznesensky 17 May '11

17 May '11

Hello there. Another question. Why nodes with similar values are grouped sequentially in non-unique hash table? It's rather a strong restriction leading to extra iterations during insertions and modifications (please, see link_point and in_place methods in hashed_index.hpp). -vv

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[review] Formal review of AutoIndex starts 5th May
by Daniel James 17 May '11

17 May '11

Hello everyone, The formal review of John Maddock's AutoIndex starts tomorrow, 5th May and finishes on Saturday 14th May. It's a little different to normal as it's a review of a documentation tool, rather than a library. We'll follow the normal procedure. Hopefully the review will also provide some experience for deciding how to deal with other tools in the future. About AutoIndex =============== The documentation describes it as "a tool for taking the grunt work out of indexing a Boostbook/Docbook document that describes C/C++ code". The documentation is online at: http://svn.boost.org/svn/boost/sandbox/tools/auto_index/doc/html/index.html AutoIndex can be downloaded from the vault: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=auto_i… The download also contains a pdf of the documentation at 'doc/auto_index.pdf', and a copy of the html documentation at 'doc/html/index.html'. You can also see some examples of the indexes it generates, in a few libraries' documentation: http://www.boost.org/libs/spirit/ http://www.boost.org/libs/type_traits/ http://www.boost.org/libs/math/doc/sf_and_dist/html/ Review guidelines ================= Reviews should be submitted to the developer list (boost(a)lists.boost.org) with '[autoindex]' in the subject. Or if you don't wish to for some reason, you can send them privately to me. If so, please let me know whether or not you'd like your review to be forwarded to the list. All reviews are appreciated, even if you don't have time for an in-depth study. It's worth a look even if you don't use docbook or the boost documentation tools yourself. As someone who uses boost, the generated indexes are intended for your use so your views do matter. Even though this isn't a library, I think the (slightly modified) general guidelines still apply: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of AutoIndex? - Did you try to use it? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? And finally, every review should answer this question: - Do you think that AutoIndex should be accepted into Boost? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. More detail on the review process is available at: http://www.boost.org/community/reviews.html I think it should be made clear that if accepted, there won't be any requirement to use AutoIndex it. Thanks in advance, Daniel James AutoIndex Review Manager

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[review][autoindex] AutoIndex review extended
by Daniel James 17 May '11

17 May '11

Hello all, The AutoIndex review is extended for another week, it's now running until Saturday 21st May. This will hopefully give people who have been busy preparing for boostcon a chance to review it in a quiet moment. I'm also interested in hearing from people who won't be using the tool directly, but might be using the indexes it generates. Or perhaps already are, since it's already been used for Boost.Spirit, Boost.Type Traits and Boost.Math: http://www.boost.org/libs/spirit/ http://www.boost.org/libs/type_traits/ http://www.boost.org/libs/math/doc/sf_and_dist/html/ It doesn't need to be a long or in depth review to be useful. The documentation is online at: http://svn.boost.org/svn/boost/sandbox/tools/auto_index/doc/html/index.html AutoIndex can be downloaded from the vault: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=auto_i… thanks, Daniel James AutoIndex review manager

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