- Boost - lists.preview.boost.org

[GSOC] XML library of Boost
by Amos Ji 12 May '13

12 May '13

Hi All, I'm a graduate student from Fudan University in China. And I hope to contribute some code to Boost during the GSOC. I've scanned the idea page. The ideas in the page are all very interesting and challenging. But what I'm interested in most is XML library, which is at the bottom of page. I think the XML format is the most popular standard for storing information so it's important for Boost to have a good XML library. However, I know Boost contains RapidXML in property_tree library to parse XML file. So what I want to make sure is I need to implement a new XML parser in this project instead of make enhancement for RapidXML. Am I correct? If so, I have some ideas to share with you. In my opinion, an XML parser must be able to do these things: 1. To Iterate over DOM nodes tree; 2. To access the values of nodes and their attributes quickly; 3. To insert or delete nodes or attribute of an exact node easily; 4. To generate new XML from the structure which stores XML in the library. And there are some optional function too: 1. To support XPATH; 2. To validate whether the XML file is valid; 3. To support various encoding; 4. To manage memory better; 5. To support regular expression. The ideas are not mature now. I'll improve them in my proposal. In fact, it's not easy to implement a perfect XML parser but I'll do my best. And I have another question. Who will mentor this XML library project? Thanks for your patience to read this email. Sincerely, Mingchao -- Amos Ji(Mingchao Ji) Master in School of Information Science and Engineering, Fudan University MSN: jmc891205(a)hotmail.com E-mail: jmc891205(a)gmail.com

14 36

[type_erasure] How to have just one behavior from relaxed without inheriting the other behaviors
by Felipe Magno de Almeida 12 May '13

12 May '13

Hello, I need to create a type_erasure::any with just this behavior from relaxed: copy assignment of any uses the copy constructor if it can't use assignable(either because assignable is missing, or because the stored types do not match). But without adding the other behaviors, is there a way to implement this? Regards, -- Felipe Magno de Almeida

2 1

[math][constants] mathematical constants page deserves to be more visible in the documentation
by Andrew Hundt 11 May '13

11 May '13

I believe the Boost.math toolkit mathematical constants are an extremely useful feature, yet it is extremely difficult to find. Every time I try to browse to it I try searching boost.org/libs, then try the math library page and cannot find the links at either of those locations. In fact, I'm not exactly sure how to browse to it and instead use saved bookmarks. I it would be worthwhile if there was some direct link or mention of it on boost.org/libs/math at minimum, and possibly even directly on boost.org/libs . Here is the mathematical constants page I am referring to: http://www.boost.org/doc/libs/release/libs/math/doc/sf_and_dist/html/math_t… Any thoughts on this idea? Cheers! Andrew Hundt

5 7

Re: [boost] Live read-only GIT mirrors of Boost trunk SVN
by Niall Douglas 11 May '13

11 May '13

> on Mon May 06 2013, Niall Douglas <ndouglas-AT-blackberry.com> wrote: > > > My experience with SubGit has been very, very good. I would *strongly* > > recommend it over git2svn. > > Why, have you got a lot of experience with both tools? You'd recommend > SubGit for what job, exactly? Does it modularize? (answer: no). Git2svn is painful. I think anyone who has used it even trivially has found it so. SubGit can map structure arbitrarily, so SVN branches need not become GIT branches, they can become tags or any other kind of git ref. You can apply filters and map one (or more) SVN repo to multiple output GIT repos using those filters, so yes it does do limited modularization. Is that modularization support particularly powerful? Definitely not. With an automated script to generate a ton load of mappings it could approach the capability of KDE's tool, albeit with no range specific filtering available. But its specific purpose is a different use case: live two-way mapping. And for that you necessarily have to restrict the flexibility of output, because they have to map in reverse. > We didn't choose svn2git at random: we started using it because KDE (a > much bigger project than Boost) used it to solve the exact same problems > Boost has to solve: modularization + Git migration. Svn2git is a completely different tool to git2svn. Svn2git is a much superior tool, albeit rather harder to configure (correctly). > You'd have to have some pretty compelling arguments, a complete plan for > migration and modularization, and be prepared to lead the effort > yourself for me to throw out years of planning and coding to use a > different tool. Do you really think you're making a reasonable > suggestion? I'm sorry you have read my confusion that way Dave. I would have hoped that after all the years we have known one another you wouldn't have interpreted my comments in that way. Just to be clear and for the record, I have no compelling arguments, no plan for migration, and I am in no way criticizing your work, your leadership, nor suggesting the throwing away of any planning or coding. I apologise unreservedly if anything in my words appeared that way. I am absolutely sure that you have given this the very deepest of thought and I - as always actually - trust your judgment. I am simply confused. > > I think it would be quite easy to set up a live perfect Git mirror of all > > Boost SVN, > > "Perfect," really? I think you are grossly underestimating some of the > strange ways that the SVN filesystem has been used over Boost's history. > >From http://subgit.com/book/index.html#branches-mapping it's clear that > the SubGit tool isn't equipped to deal with them properly. For example, > there's no revision range limiting in the branch mapping, a feature of > svn2git that we actually *need* to use. Perfect for me means that HEAD and releases work perfectly. I personally feel little priority about perfect preservation of history. > > do a transition period where SVN is writeable but GIT read only, and > > then one day the switch is flipped and it goes the other way > > round. That way anyone dependent on SVN keeps on working, but without > > write access. > > Again, I think a two-way mirror could be a really nice addition to the > existing transition plan, if someone is willing to put in the elbow > grease to set it up. Are you volunteering? We can talk about this at C++ Now next week, but if we were to coordinate our efforts and I have definite approval and support from Boost SC, I have no objection to volunteering for this. There is also the matter that SubGit would probably need some money paid for it as a matter of good faith. I would emphasize that a successful two way mirror does impose substantial restrictions on the variety of modularization possible so long as the mirror is active. That probably is unacceptable to you given your apparent plans. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

2 1

Re: [boost] Git Modularization Ready for Review
by Niall Douglas 11 May '13

11 May '13

> Niall Douglas <ndouglas(a)blackberry.com> writes: > > > Me personally I'd just chuck away any unmappable historical information. > > Chalk it up to a cost of transition. If they really need the history, > > they can go fetch it from the read-only SVN repo. > > I see you've not been keeping up with the list lately ;) Daniel et. al. > suggested doing just that a few months ago and was met with such a chorus of > criticism, they didn't really have a choice but to fix it. Never actually was on this list, not ever, until recently as it's a lot of extra reading. Been involved with Boost for over a decade though. > Personally, I agree with the chorus. After all, the point of a VCS is to have a > history of the code's evolution to a point. The VCS, be it SVN, Git, whatever, is > just a means to get that history. Jetissoning the ends for the means seems > misguided. No, it's a cost of doing an upgrade. Those of you who ever migrated a large CVS to SVN transition know what I mean: stuff gets lost, and actually it isn't important enough to preserve that it requires a quadrupling of transition effort when a read-only copy of the old technology repo is good enough. Distributed SCM is much more dimorphic again, and you *have* to accept some data loss. Let me put this another way: those who want no history loss ought to be the ones volunteering the additional time to preserve history. What actually happens sadly is then the argument becomes we must stick with whatever the old technology is, because people will choose a small reduction of productivity every day over fixing tooling once and for all ("programmers program, they don't do tooling"). I *still* find CVS in use in places because "history must never ever be lost", and given the anti-productivity nature of CVS that costs far more in present developer time than accepting a 5% or 10% history loss, most of which will never significantly matter anyway because it occurs on the edges where SCMs dimorph. > What happens in a few years time when Git is replaced with the next big thing? > Do we lose the history again? And then again when that gets replaced too? That's exactly what happens. Bitrot is always inevitable in the long run. Here call it "non-fatal bitrot" :) My only red line is corruption of past and present source code releases. It must *always* be possible to check out tag X and build release X. Other than that, I'm flexible, including loss of branch integrity, because in the end if that branch is really important its owner will manually fix up the damage. > > I fear that if modularization is taken to its logical extreme, you > > could see submodules get out of step with other submodules. You may of > > course have already anticipated this and have implemented something I > haven't realized. > > As I said, I am confused. > > Can you explain a bit more about what you mean by out-of-step? The whole > point of modularising the code is to *help* modules to get out-of-step and > therefore be easier to develop and test independent of what other Boost > libraries are doing. But perhaps you mean something else? Well, the Git way of helping stuff get out of step is that everyone gets their own full copy of the whole repo, and their copy is just as important as anyone else's copy. You clone, you develop and test, and optionally push changes elsewhere which could be your friend, your team, your employer, or of course some central authoritative copy. So I'm afraid I just don't get the present design for a library as small and as tightly integrated as Boost. Something huge and cleanly separated like KDE sure, but for Boost I suspect it's overkill. Unless Boost plans to grow 10x in the next three years that is. > > [1]: By findable I mean that when Boost library users do #include > > <boost/whatever> they get the main Boost repo version, not the > > submodule version. I absolutely would expect an automated tool to pull > > headers from submodules, check them for ABI breakage and push them > > into the main repo. My point is that some sanity check ought to be there. > > I'm not following why you would want to do this. Perhaps you can explain what > problem you are anticipating and how this would solve it? Most of Boost is implemented in headers, very much unlike KDE or most other C++ libraries. Moreover, those headers are quite brittle, unlike KDE or most other C++ libraries. If broken into submodules, I can see an apparently innocent change in submodule X appearing to compile and be okay in developer X's set of submodule clones, but silently be a breaking change with a simultaneous change in submodule Y by developer Y. Why this matters is because when in git you go to push, git will force you to merge before push and at that point you "see" the breakage by a conflict appearing (hopefully) and if not then your immediate next compile will fail. With the submodule approach that doesn't happen, so you *don't* see the breakage till much later when the regression tests suddenly start failing. I'm a great believer in refusing to let programmers commit code which breaks other code rather than nagging them later to fix an earlier commit. The point of failure notification ought to be as close to cause as possible. > I also don't get what 'findable' means. What would a non-findable header be? Any internal header only findable by internal implementation. What I'm basically suggesting is an approach where the master repo keeps a gold candidate set of headers automatically extracted regularly from the submodules. Then on push a hook can do appropriate black magic to force the pusher to merge headers before the push. Then stuff which is broken appears broken as soon as possible, rather than suddenly emerging many days later. Does this make sense? Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

3 2

Boost build broken on the trunk
by Edward Diener 11 May '13

11 May '13

After getting the latest Boost from the trunk, and after running bootstrap I try '.\b2 install --prefix=c:\programming\bin' and get: ---------------------------------------------------------------------- Performing configuration checks - 32-bit : yes - arm : no - mips1 : no - power : no - sparc : no - x86 : yes - has_icu builds : no warning: Graph library does not contain MPI-based parallel components. note: to enable them, add "using mpi ;" to your user-config.jam - zlib : no - iconv (libc) : no - iconv (separate) : no - icu : no - icu (lib64) : no - message-compiler : yes - gcc visibility : no - long double support : yes warning: skipping optional Message Passing Interface (MPI) library. note: to enable MPI support, add "using mpi ;" to user-config.jam. note: to suppress this message, pass "--without-mpi" to bjam. note: otherwise, you can safely ignore this message. warning: No python installation configured and autoconfiguration note: failed. See http://www.boost.org/libs/python/doc/building.html note: for configuration instructions or pass --without-python to note: suppress this message and silently skip all Boost.Python targets - zlib : no (cached) C:/Programming/VersionControl/boost/tools/build/v2/build\virtual-target.jam:1099 : in virtual-target.register-actual-name from module virtual-target error: Duplicate name of actual target: <pc:\programming\bin\lib>libboost_date_t ime-vc110-mt-gd-1_54.lib error: previous virtual target { common%common.copy-libboost_date_time-vc110-mt- gd-1_54.lib.STATIC_LIB { msvc%msvc.archive-libboost_date_time-vc110-mt-gd-1_54.l ib.STATIC_LIB { msvc%msvc.compile.c++-gregorian\greg_month.obj.OBJ { gregorian/g reg_month.cpp.CPP } } { msvc%msvc.compile.c++-gregorian\greg_weekday.obj.OBJ { g regorian/greg_weekday.cpp.CPP } } { msvc%msvc.compile.c++-gregorian\date_generat ors.obj.OBJ { gregorian/date_generators.cpp.CPP } } } } error: created from ./install-proper-lib-static error: another virtual target { common%common.copy-libboost_date_time-vc110-mt-g d-1_54.lib.STATIC_LIB { msvc%msvc.archive-libboost_date_time-vc110-mt-gd-1_54.li b.STATIC_LIB { msvc%msvc.compile.c++-gregorian\greg_month.obj.OBJ { gregorian/gr eg_month.cpp.CPP } } { msvc%msvc.compile.c++-gregorian\greg_weekday.obj.OBJ { gr egorian/greg_weekday.cpp.CPP } } { msvc%msvc.compile.c++-gregorian\date_generato rs.obj.OBJ { gregorian/date_generators.cpp.CPP } } } } error: created from ./install-proper-lib-static error: added properties: <log-api>winnt error: removed properties: <log-api>generic C:/Programming/VersionControl/boost/tools/build/v2/build\virtual-target.jam:484: in actualize-no-scanner from module object(file-target)@4017 C:/Programming/VersionControl/boost/tools/build/v2/build\virtual-target.jam:134: in class(a)virtual-target.actualize from module object(file-target)@4017 C:/Programming/VersionControl/boost/tools/build/v2\build-system.jam:720: in load from module build-system C:\Programming\VersionControl\boost\tools\build\v2/kernel\modules.jam:289: in im port from module modules C:\Programming\VersionControl\boost\tools\build\v2/kernel/bootstrap.jam:139: in boost-build from module C:\Programming\VersionControl\boost\boost-build.jam:17: in module scope from module ------------------------------------------------------------------------ This is on Windows but the same thing occurs on my Linux distros. Cannot this be fixed ? I posted the same message for Linux failure on the Boost Build mailing list but received no response.

3 4

[bootstrap/1.53] jam0.exe crashes when bootstrapping for VC2012 AMD64
by rjeczalik 11 May '13

11 May '13

Hi, I'm trying to build Boost 1.53 using VC2012 amd64 (toolset=msvc-11.0 address-model=64) and Windows Server 2012 Standard. Bootstrapping fails with jam0.exe crash - some crash info: Crash stacktrace: ntdll.dll!000007f9bc781069() KernelBase.dll!000007f9b978764e() KernelBase.dll!000007f9b97d3658() jam0.exe!_findnext64i32(__int64 hFile, _finddata64i32_t * pfd) Line 165 jam0.exe!file_dirscan(_object * dir, void (void *, _object *, int, __int64) * func, void * closure) Line 180 jam0.exe!builtin_glob(frame * frame, int flags) Line 718 jam0.exe!function_run(_function * function_, frame * frame, _stack * s) Line 3390 jam0.exe!evaluate_rule(_object * rulename, frame * frame) Line 264 jam0.exe!function_call_rule(_jam_function * function, frame * frame, _stack * s, int n_args, const char * unexpanded, _object * file, int line) Line 468 jam0.exe!function_run(_function * function_, frame * frame, _stack * s) Line 3950 jam0.exe!parse_file(_object * f, frame * frame) Line 57 jam0.exe!main(int argc, char * * argv, char * * arg_environ) Line 488 jam0.exe!__tmainCRTStartup() Line 241 jam0.exe!mainCRTStartup() Line 164 kernel32.dll!000007f9b9de167e() ntdll.dll!000007f9bc7a3501() Line where it crashed was: if (!FindNextFile((HANDLE)hFile, &wfd)) { I've tried to watch the values of arguments passes to FindNextFile() - hFile looked like proper handle, however wfd.cFileName and wfd.cAlternateFileName contained garbage. Is this a known issue for 1.53? I've compiled version 1.52 using the same environment and the same configuration and everything went ok, I did not manage to reproduce the crash. It looks like only version 1.53 is affected. Regards, Rafael Jeczalik

5 5

Re: [boost] [log] Patch: rotating file collector
by Andrey Semashev 10 May '13

10 May '13

On Tue, Apr 23, 2013 at 3:58 PM, Alexander Arhipenko <arhipjan(a)gmail.com>wrote: > > I've added implementation of rotating file collector - > the patch against boost log trunk attached. > This is not the final version, I'm going at least to finish most of the > TODOs. > > However, it would be nice to receive feedback and questions from > library author as well as from people interested in this feature. > > Andrey, could you please find several minutes to review the attached patch? > Thanks for the patch. I didn't look deeply into it yet but from the first glance it looks like you changed the existing file collector rather than introduce an alternative one. Am I right? If so, could this be made as a pure addition rather than modification? I would prefer to keep the current behavior also available for the users. Also, I would like to discuss following question with you : > rotate_file invocation in ~text_file_backend - > I would prefer to have this call during text_file_backend construction > phase. > I'll have to take a closer look later to answer that but it seems odd to have to rotate something when nothing have been written yet. The rotate_file call is intended to place the written file to the storage governed by the collector, and at construction this file hasn't been created yet. Could you describe why you need this?

3 7

[algorithm] More general purpose algorithms?
by Sai Kiran Talamudupula 10 May '13

10 May '13

Hi, I am new to using boost libraries. I want to contribute to [boost.algorithm]. I see that there is scope for adding more general purpose algorithms in the library now. If I might have some ideas, is this the right place to propose and discuss them? Do I need to follow any procedure and/or address a specific person? Best, Saki.

2 1

Wanted: reviewers for boost.test doc overhaul
by legalize+jeeves＠mail.xmission.com 10 May '13

10 May '13

[Please do not mail me a copy of your followup] As per the "What do we do about boost.test?" thread last year, the biggest complaint seemed to be the documentation. I'm overhauling the documentation using quickbook and I'd appreciate incremental feedback along the way. Any takers? -- "The Direct3D Graphics Pipeline" free book <http://tinyurl.com/d3d-pipeline> The Computer Graphics Museum <http://computergraphicsmuseum.org> The Terminals Wiki <http://terminals.classiccmp.org> Legalize Adulthood! (my blog) <http://legalizeadulthood.wordpress.com>

5 4

[TypeErasure] references
by Chapman, Alec 10 May '13

10 May '13

Hi Steven, I have a somewhat-generic type erasure class that I would like to switch to yours. The main difficulty I can see is in the way capturing by reference is handled. The approach I take in my class is to pass a boost::reference_wrapper to the constructor: typedef mpl::vector<copy_constructible<>, type_id_<>, incrementable<> > requirements; int i = 0; any<requirements> x(boost::ref(i)); // capture i by reference ++x; // i == 1 any<requirements> y(x); // makes a copy of i ++y; // i == 1, any_cast<int>(y) == 2 My motivation is that I have a bunch of template functions already written that I often call directly, but in other cases I need to compile them separately by instantiating them with any<...>: ---------------------- module 1 ------------------------- // some long algorithm that I don't want to modify to be aware of any<...> template<class T> void f(T& t) { ++t; T t2 = t; ++t2; // do something with t2 } // make a type-erased version for separate compilation void any_f(any<requirements>& x) { return f(x); } -------------------- module 2 ---------------------------- // provide a thin wrapper that applies type erasure before calling any_f template<class T> void f_fwd(T& t) { any<requirements> x(boost::ref(t)); any_f(x); } // some function that needs to call f void g(int& i) { // do something with i... // then pass it to f f_fwd(i); } Is something like this possible with your method? Are there advantages that I'm not seeing to having the type signature contain information about whether the object is held by reference? Thanks, Alec

3 6

Re: [boost] Git Modularization Ready for Review
by Niall Douglas 09 May '13

09 May '13

> > I'm far more confused as to why? Surely the conventional approach is to > > convert a SVN repo to GIT. > > Good luck with that, given the way SVN "branches" (really directories) > have been used in Boost's history. No automated tool is able to > determine how to map those things properly onto Git branches. You can > see evidence of that in repositories.txt (look at the "build" repository > declarations for example). Me personally I'd just chuck away any unmappable historical information. Chalk it up to a cost of transition. If they really need the history, they can go fetch it from the read-only SVN repo. > You act as though we haven't been thinking about how to do this well and > working on it for years already. We're quite well-aware how submodules > work. The use of submodules by most developers is supposed to be a > temporary transitional measure, since modularization is designed to > allow you to work with only the parts of Boost relevant to your project. You have mistaken my confusion for criticism. I am not criticizing. I am confused. > > Also, how is Boost going to manage dependency breakage across multiple > > submodules? > > What is "dependency breakage?" Generally speaking Git submodules are for loosely coupled relations because of how Git implements submodules. Some of Boost's constituent libraries do meet that definition (BPL, BGL, Math). Some do not, as they are too essential because so many other libraries depend on them (anything likely to enter the standard with TR2, the MPL, the PPL etc). I fear that if modularization is taken to its logical extreme, you could see submodules get out of step with other submodules. You may of course have already anticipated this and have implemented something I haven't realized. As I said, I am confused. > > Are you planning to keep headers in one monolithic repo > > No > > > but keep anything resulting in a DLL/SO in a submodule? Or are you > > planning to break out the headers into submodules too? > > Yes; it's already done, modulo some expected adjustments due to the > review I am requesting. One solution is to require all findable headers to live inside the main Boost repo [1], and only implementation to reside in submodules. That keeps minds focused on dependency management. [1]: By findable I mean that when Boost library users do #include <boost/whatever> they get the main Boost repo version, not the submodule version. I absolutely would expect an automated tool to pull headers from submodules, check them for ABI breakage and push them into the main repo. My point is that some sanity check ought to be there. > > I can see it becoming quite easy for submodules or branches or forks > > thereof to get out of step with one another. > > That's a *good* thing. We're trying to decouple. Most libraries will > be developed against the previous release of their dependencies. > > > I can see the present submodule heavy approach introducing a lot of > > anti-Git workflow because those submodules inside the boostorg > > organization are treated as special compared to other submodules. > > I don't have any idea what you mean here Git generally has you clone the authoritative master repo, you create a branch, make your changes. Once you're finished, you fetch latest master, merge into your branch until it's up to date, then generate a patch or pull request from your branch to authoritative master. Whoever gatekeeps that repo does the merge. Where I'm getting confused - again - is that it would seem that the submodule repos inside the Boost org section on github are the ones to be regression tested and used to assemble releases. So, instead of treating all git repos as one-among-many as say Linux would do, we've got a special "high" gold candidate set of git repos and then all other git repos. This appears to add an extra layer of syncing and merging, because surely Boost admin has the power to modify any of the high gc set of repos. I'm not saying that this choice isn't for very good reasons. It's just that from my experience a submodule heavy git repo with lots of tightly coupled submodules becomes a royal PITA for end users because you get all sorts of weird obtuse breakages for apparently no reason at the time. Maybe of course it's just me, and I have some mental block others don't have. And I absolutely agree that other projects such as KDE have adopted your approach and it seems to work for them. However Boost is not KDE. In my mental model of the world, Boost more resembles the Linux kernel in terms of interdependencies and size. KDE has a vastly more stable intra-module ABI and much more loosely coupled submodules. This interpretation may be a mistake of mine. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

2 1

Re: [boost] The file boost/detail/endian.hpp needs to be set up for your CPU type
by Niall Douglas 09 May '13

09 May '13

> > How does one write a proposal to the C++ committee? > > http://isocpp.org/std/submit-a-proposal > > > I'll do it. This is a > > problem that probably comes up a lot, people then figure out some > > clumsy workaround and then forget about it. These workarounds are > > just that, and they impact the bottom line as programmers try and > > figure out some way of figuring them out. > > > > This should be standard. No workaround required. > > Jonathan hit the nail on the head.The C++ standard is essentially an open source > software project staffed entirely by volunteers. There is no such thing as > something that "should be standard" - there are only things that someone has > written a proposal for, and then gone to the trouble of shepherding through the > standardization process. Also, allocate a minimum of at least one year to achieve a successful shepherding, and that's for an obvious, uncontroversial change. ISO standards has large barriers to entry and for good reason: only those with stamina and the ability to repeatedly rewrite proposals to correctly include feedback will succeed. I'm not saying don't do it, because if there's a problem it should be fixed. I am saying that most of the work in writing a proposal isn't in writing and submitting one as that part is straighforward, it's in the shepherding part as Beman points out. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

1 0

The file boost/detail/endian.hpp needs to be set up for your CPU type
by Adrian_H 09 May '13

09 May '13

I saw this error and was wondering, can the endianness of a compiler not be determined through templates instead of using <endian.h>? Using macros seems to be pretty old-school and if headers are not updated could be just flat out wrong. -- View this message in context: http://boost.2283326.n4.nabble.com/boost-The-file-boost-detail-endian-hpp-n… Sent from the Boost - Dev mailing list archive at Nabble.com.

7 14

Re: [boost] [gsoc-2013] Boost.Thread/ThreadPool project
by Niall Douglas 09 May '13

09 May '13

> IIUC, the question is related to Qt's API for integrating with Qt's event > dispatcher, which (IIUC again:p) is used by QApplication, QCoreApplication and > QThread. > > Apologies if I'm off target here. Correct. I think the gold standard is a thread pool implementation which seamlessly allows Boost.ASIO to be combined with Qt's event dispatcher all in the single implementation. In other words, the thread pool can cope with multiple simultaneous event dispatcher implementations. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

1 0

[log] Is it lock free ?
by adrien courdavault 09 May '13

09 May '13

Hi I'm really interested by the new Log library. I would like to know if there is a part of this API that could be wait free, not the << operator perhaps, but a specific function to log a message without having to worry about a malloc or lock called inside the library. I would like to use this from a time critical thread. thank you

3 5

[predef] Status and review results?
by Rene Rivera 09 May '13

09 May '13

Just a quick message to mention that I've finished all the review related changes to the Predef library. And done some of the future tasks on the library. In particular the addition of endianness definitions and the moving of MinGW as a platform instead of a compiler (and hence the addition of BOOST_PLAT category of macros. And the one question I have is.. When will the review results of the library be decided on? I ask for two reasons. One, the obvious, is just to know if it's accepted or not. And to know if it's not accepted and hence that I should spend time to recreate a "boost/detail/endian.hpp" header that implements the Predef logic for endian detection. Note the project move to Github earlier this year (in preparation for the Boost git move). You can find the project at < https://github.com/grafikrobot/boost-predef>, and browse the current documentation at <http://tinyurl.com/cqqhhev>. -- -- -- Grafik - Don't Assume Anything -- Redshift Software, Inc. - http://redshift-software.com -- rrivera/acm.org - grafik/redshift-software.com -- 102708583/icq - grafikrobot/aim - grafikrobot/yahoo

8 31

[chrono/date] Two axes for a date design: validity check and representation and an essence date class/factory
by Vicente J. Botet Escriba 09 May '13

09 May '13

Hi, I would like to discuss about some alternatives to take in account the following use case "Reset a date if it resulting date is valid and report if this succeeds" when we have two axes of variation on the date design. Let me add two parameters to the possible date class. * validity: unchecked/checked * representation: serial, ymd(calendar), iso_ordinal, iso_week... date<serial, unchecked> is an unchecked serial date. It corresponds +/- to the N3344 date suggestion. date<ymd, checked> is a checked ymd date. It corresponds +/- to the H.H 2011 date proposal. WARNING !!! I'm not saying that a template class is a good thing, it is just to state clearly the features of the date. N3344 suggest a date::set_if_valid_date function. date<serial, unchecked> ud=...; if (ud.set_if_valid_date(y,m,d)) { // xx } else { // yy } But if we want to do as for the date constructors we will need multiple overloads again for this function :(. As show on this ML serial+unchecked dates validation could have some surprises. We can get the same service building a ymd date that can provide a way to be validated. //------------- // Validity check done when is_valid() is called on ymd_date. date<serial, unchecked> dd=...; date<ymd, unchecked> yd(y,m,d); if (yd.is_valid()) { // CHECK dd = yd; // xx } else { // yy } Instead of using explicitly date<ymd,unchecked> we can use a make_essence() factory that returns some kind of tuple essence_date<year,month,day> that is not a date, but its essence. It contains everything needed to build a date. This essence should be implicitly convertible to any date. The make_essence_date() factory supports all the different orders of parameters. The operator/() expression would also create an essence date. // -------------- //No validity check is done. date<serial, unchecked> ud = make_essence(y,m,d); date<serial, unchecked> ud1 = m/d/y; This essence dates support date validity, that is provides a is_valid() function. // -------------- // Validity check done when is_valid() is called on essence. date<serial, unchecked> ud; auto d = y/m/d; if (d.is_valid()) { // CHECK ud = d; // xx } else { // yy } //-------------- // Validity check done at construction of cd. serial_date<checked> cd = make_essence(m,d,y); //serial_date<checked> cd = m/d/y; Summary: IMO Having checked and unchecked dates with several representations could help to make dates interface more precise and concise. Checked dates are always valid. Dates with a specific representations would provide only, as suggested by Howard, only the functions that are efficient. The use of essence dates factories simplify the interface of all the date classes construction. Only 1 constructor by representation needed independent of the parameters order date(essence<ymd> &&); date(essence<serial> &&); date(essence<iso_ordinal> &&); date(essence<iso_week> &&); Comments welcome, Vicente P.S.The essence date classes and the contextual dates are quite related. I prefer to let this 3rd contextual axe of variation out of the current scope. I will try to integrate it soon.

2 3

[trac] Add component for Boost.Log
by Andrey Semashev 09 May '13

09 May '13

Hi, Not sure whom to ask, but could someone create a component "log" for Boost.Log in Trac? I (andysem) am the maintainer. Thanks.

2 2

JSON parsing library project for GSoC
by Olexandr Popilovsky 09 May '13

09 May '13

Hi. My name is Olexandr Popilovsky and I'm a student of Taras Shevchenko National University of Kyiv. I made a proposal for JSON parsing library and I would like to know that can I be accepted for this project and if yes, what I should to do to increase my chances (demo or smt.). thanks. waiting for your answer =)

4 6

Company copyright release examples
by Brendon Costa 08 May '13

08 May '13

I am looking into asking the company I work at for an official written "release" on the copyright for work I with to contribute to boost as per the description at: http://www.boost.org/development/requirements.html I will be developing this in my own time outside of work hours but I will need this release due to clauses in my contract and the relationship that the proposed library would have to my normal work. Are there any examples of what this release should look like for boost to accept it? I think having a sample release available on the page I linked to above would be really useful. Thanks, Brendon.

4 6

[iterator] Silent-but-deadly bug in iterator_facade category
by Gabriel Redner 08 May '13

08 May '13

Hi folks, I've stumbled across a nasty problem with iterator_facade in which code which appears correct and compiles fine can cause runtime problems. Consider an iterator_facade which just wraps a random access iterator and applies a transformation to it: char transform(int i) { return 'a'; } struct my_iterator : public boost::iterator_facade<my_iterator, char, // value_type std::random_access_iterator_tag, // *** char> // reference { my_iterator(const std::vector<int>::iterator& it) : _it(it) {} char dereference() const { return transform(*_it); } bool equal(const my_iterator& other) const { return _it == other._it; } void increment() { ++_it; } void decrement() { --_it; } void advance(int n) { std::advance(_it, n); } int distance_to(const my_iterator& other) const { return other._it - _it; } private: std::vector<int>::iterator _it; }; Now if I have an STL-style function which is overloaded on the iterator category, clearly the random-access version will be selected. template <typename TIterator> void funcImpl(TIterator it, std::input_iterator_tag) { std::cerr << "Running func treating 'it' as input iterator\n"; } template <typename TIterator> void funcImpl(TIterator it, std::random_access_iterator_tag) { std::cerr << "Running func treating 'it' as random access iterator\n"; } template <typename TIterator> void func(TIterator it) { funcImpl(it, typename std::iterator_traits<TIterator>::iterator_category()); } In the line marked ***, the docs suggest I should use boost::random_access_traversal_tag instead of std::random_access_iterator_tag - but when I do, the program no longer selects the random access version of 'func', choosing the forward-only version instead! The iterator_category of my_iterator ends up as: boost::detail::iterator_category_with_traversal<std::input_iterator_tag, boost::random_access_traversal_tag> The reason I called this a 'deadly' bug is that std::advance is suddenly a deathtrap: std::advance(it, -1); This is fine and legal for random access iterators, but if the forward-only version gets called instead, the behavior is undefined (on my system, it loops endlessly). The compiler doesn't complain either way - the problem surfaces only at runtime. Does the problem lie with iterator_category_with_traversal? It looks like it's intended in this case to be convertible to either std::input_iterator_tag or std::random_access_iterator_tag, but clearly something is wrong with the latter conversion. Any ideas? Thanks, -Gabe

7 14

[gsoc 2013] draft proposal for chrono::date
by Anurag Kalia 07 May '13

07 May '13

Hi, I mistakenly sent this draft as a reply to personal email of Vicente. I am sorry! Here it is again, verbatim. One related question though. I still haven't got the hang of a Mailing List. Is there a software takes the pain away from it. For example, I use outlook.com and '>' get appended in front of only the start of paragraph making it wholly unreadable. Thanks, Anurag Kalia. ---------------------------------------- > Date: Sat, 27 Apr 2013 18:14:09 +0200 > From: vicente.botet(a)wanadoo.fr > CC: anurag.kalia(a)outlook.com > Subject: Re: [boost] [gsoc 2013] draft proposal for chrono::date > > Le 27/04/13 16:58, Anurag Kalia a écrit : > >> I understand that you want to design your own library, I did the same, > >> but getting a coherent design would take you some time. > >> I suggest you to start with the H. Hinnant proposal as a reference and > >> state what you want to added, changed or removes. State clearly why do > >> you want these changes, what would be improved/solved. > >> > >> Don't forget to inspect the threads/discussion related to the H.Hinnant > >> proposal, and the paper N3344 Toward a Standard C++ 'Date' Class > >> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3344.pdf > > Hi Vicente, > > > > Thanks a lot for the exhaustive reply! I will get back to you after going through all the things you pointed out and also the paper you forwarded. But I have one quick question for now, from where can I start my search for the threads and discussions around this date proposal? > > > > > > > Hi, > > There were some interesting exchanges in > https://groups.google.com/forum/?fromgroups=#!forum/kona-date-lib > > I guess that if you request to the administrator s/he will be able to > give you read access to the existing threads (there are not too much). > > Best, > Vicente > I have finally implemented some representative functions in date class and calendar to get a better idea of the proposal. I have dropped the JDN storage for another implementation that I thought of in the middle of the night. I think it is a hybrid approach between serial and field-based implementations. Off the top of my head, without any alternative implementations at hand and benchmarks too, I can't think of something inherently wrong in it. I would really like to hear its gotchas, if any. I have overhauled my proposal on the basis of it. It doesn't contain other headings like about me etc for today. I have tried to incorporate all the previous points you noted before and have also tried to keep naming consistent. I did use uppercase constants in there but they are meant to be private. Is that okay? I knew little about the benchmarks before you sent me that paper. From what I got, they just iterate over a significant period of time and note the start and ending time. Is it more than that? And should I make them before or after I have multiple implementations in hand. I could get hold of your and Howard Hinnant's implementations for them, but then the APIs would have to line up, wouldn't they? Hope you find my proposal better this time around. With an open ear, Anurag Kalia.

9 95

[GitHelp] bootstrap.bat calls missing build.bat
by legalize+jeeves＠mail.xmission.com 07 May '13

07 May '13

[Please do not mail me a copy of your followup] OK, so I am experimenting with modular boost, following the instructions here: <https://svn.boost.org/trac/boost/wiki/TryModBoost> I cloned and did the submodule update. I didn't have CMake; is this why I experience a problem? What exactly does 'cmake -P forward_header.cmake' do? When I run boostrap.bat it fails early with an attempt to call build.bat which doesn't exist. Thanks for your time. -- "The Direct3D Graphics Pipeline" free book <http://tinyurl.com/d3d-pipeline> The Computer Graphics Museum <http://computergraphicsmuseum.org> The Terminals Wiki <http://terminals.classiccmp.org> Legalize Adulthood! (my blog) <http://legalizeadulthood.wordpress.com>

3 5

[quickbook][random] Build under doc/ broken?
by John Maddock 07 May '13

07 May '13

I'm not sure if this is a random or quickbook issue, but building the doc build under doc/ fails with current quickbook trunk. Any ideas? Thanks, John.

2 1