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[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.

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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 =)

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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.

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[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

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[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.

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[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>

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[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.

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[wave] trace doesn't output errors.
by Adrian_H 07 May '13

07 May '13

I've got a really annoying and difficult to track down PP error. I'm attempting to use wave to see the expansion, but it is slow going. The output is correct, in both the g++ PP and the wave parser. g++ states: *error: macro "BOOST_PP_SEQ_ELEM_III" requires 2 arguments, but only 1 given*, wave states *warning: too few macro arguments: BOOST_PP_SEQ_ELEM_III*, but when I try using the tracer it doesn't say when this occurs. Is it possible to turn this on? Or is there no 'on' and I have to go into the wave code and code it on? If the latter, where would I do this? Thanks, Adrian -- View this message in context: http://boost.2283326.n4.nabble.com/boost-wave-trace-doesn-t-output-errors-t… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Git Modularization Ready for Review
by Niall Douglas 07 May '13

07 May '13

> After substantial work, including massive changes by me and Daniel Pfeifer to > KDE's svn->Git conversion tool, we have captured every Boost SVN commit in a > Git repository. You can view the results at > > http://github.com/boostorg > http://bitbucket.org/boostorg > > Daniel and I are ready to accept your feedback on the results of modularization, > and especially your pull requests containing edits to the ruleset. I will the > steering committee to establish a formal review period, though. I'm a bit confused. This looks like a hand written map of parts of Boost SVN onto multiple GIT repos. Am I understanding correctly? I'm far more confused as to why? Surely the conventional approach is to convert a SVN repo to GIT. Then people hive off their particular bits into submodules as and when they themselves decide and they are ready. It looks here that Boost has decided on skipping the intermediate stage and going straight to submodules. That sounds awfully fraught: it also demands a lot from those library maintainers not familiar with Git. Submodules are extremely different to SVN externals - they're a very light link, and in many occasions Git does not auto-update submodules even when you tell it (i.e. it'll fetch, but silently not checkout head if it thinks you might lose data). Also, how is Boost going to manage dependency breakage across multiple submodules? Are you planning to keep headers in one monolithic repo but keep anything resulting in a DLL/SO in a submodule? Or are you planning to break out the headers into submodules too? I can see it becoming quite easy for submodules or branches or forks thereof to get out of step with one another. 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'm confused. Sorry. I'm probably not making any sense. Is there a design rationale document somewhere? I can't see one up to date on Google. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

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Re: [boost] Live read-only GIT mirrors of Boost trunk SVN
by Niall Douglas 07 May '13

07 May '13

> > All branches and tags, as far as I can tell, are mirrored correctly. I've > > set a cron job every 24 hours. Theoretically if we had an authors mapping > > file it would work in the opposite direction too i.e. be read-write. > > Nice. You can find a complete author mapping here: > https://github.com/ryppl/Boost2Git/blob/master/authors.txt Arse. I only rebuilt the mirror this weekend because it wasn't mirroring tags/release/* which has obvious value. Fixed now. > > My next task is to live mirror a github repo into Boost Sandbox. Currently > > SubGit segfaults on this due to the complex SVN properties auto-translation > > which requires a specially marked up .gitattributes, but the author is very > > keen to fix the problem. In theory then it ought to just work. > > > > Any mistakes in my Boost mirror, or any problems, or even thoughts are > > gratefully received. > > Don't put too much effort into this; Boost SVN->Git modularization is > just about ready for review :-) My experience with SubGit has been very, very good. I would *strongly* recommend it over git2svn. The company which develops it has been very impressive in response rate and going the extra mile to help me figure out problems. BTW Dave with much help from the same company I've figured out the opposite flow: automated Git => Boost SVN. It took a lot of trial and error to work around Boost's MIME type and EOL conventions, but you can see an exact automated mirror of https://github.com/ned14/TripleGit at http://svn.boost.org/svn/boost/sandbox/triplegit/. I had to squash history because of the MIME type problems though :( but from now on it should be live. I think it would be quite easy to set up a live perfect Git mirror of all Boost SVN, 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. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

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[chrono/date] Unit specifiers arithmetic
by Vicente J. Botet Escriba 07 May '13

07 May '13

Hi, Moving from checked dates to unchecked ones by default and forcing to user the Unit specifiers year/month/day in any date constructor (even the unchecked ones) has some ugly consequences. Note that I was able to build an unchecked date as date d(2013,5,6, no_check); Given year y; month m; day d; the following will not compile now as the constructors expects a year but y+1 is an int. date d(y+1, m, d); The user needs to type date d(year(y+1), m, d); Is this what we want to provide to the user or should we add basic arithmetic on these unit specifiers? Best, Vicente

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Re: [boost] [gsoc-2013] Boost.Thread/ThreadPool project
by Niall Douglas 07 May '13

07 May '13

> Le 30/04/13 17:16, Niall Douglas a ?crit : > >> Le 29/04/13 21:35, Niall Douglas a ?crit : > >> Could you explain me what a central asynchronous dispatcher is? > > An asynchronous procedure call implementation. Here's Microsoft's: > > http://msdn.microsoft.com/en- > us/library/windows/desktop/ms681951(v=vs.85).as > > px. Here's QNX's: > http://www.qnx.com/developers/articles/article_870_1.html. > > Boost.ASIO is the same thing for Boost and C++ but implemented by > > application code. It is *not* like asynchronous POSIX signals which are a > > nearly useless subset of APCs. > I don't see the term "central asynchronous dispatcher" used in any of > the links. Could you clarify what it is? I have to admit I'm struggling to see where your block is, but Dave Abrahams often found the same with me, so it must be me. A central asynchronous dispatcher is the loop which sends callbacks/events to be invoked/processed by other execution contexts. Every OS has at least one in the kernel. Most GUI toolkits like Qt have one. Boost has at least one in the form of Boost.ASIO. The central means one execution context does the dispatch. The asynchronous means that callbacks are processed by recipients asynchronous to the dispatcher. And dispatcher, well that dispatches. > >> If not, please could you elaborate what kind of optimizations can be > >> obtained? > > If you have transactional memory in particular, you gain multi-CAS and the > > ability to (un)lock large ranges of CAS locks atomically, and a central > > dispatcher design can create batch lists of threading primitive operations > > and execute the batch at once as a transaction. Without TM, you really need > > the kernel to provide a batch syscall for threading primitives to see large > > performance gains. > I'm really lost. Multi-word Compare-And-Swap (MCAS) is one of the biggest gains from Transactional Memory. Indeed WG21 has SG5 dedicated to integrating TM into C++17. Some models of Intel's Haswell come with hardware TM assist. I'd take a reasonable guess that MCAS will benefit centralized kernel-based threading primitives architectures such as Windows NT more than decentralized threading primitive architectures such as POSIX. That said, I could see Linux using TM for batch multi-kernel-futex ops, though I'd have to say implementing that without breakage would be daunting. Either way, a central asynchronous dispatcher has information a decentralized implementation does not. That opens more scope for optimization. > > Boost.ASIO's core is boost::asio::io_service. That is its dispatcher > > implementation which each dispatch execution context being executed via > > boost::asio::io_service::run() which is effectively an event loop. Third > > parties then enqueue items to be dispatched using > > boost::asio::io_service::post(). You don't have to run Boost.ASIO using > > multiple threads: it can be single threaded. > > I could not comment until I understand what Boost.ASIO provides and it > can interact with thread_pools :( Boost.ASIO provides a per-thread capable event loop implementation. That automatically makes it an example of a thread pool manager. You may find N3562 Executors and schedulers coproposed March 2013 for Bristol by Google and Microsoft of use to you in understanding the relation between thread pools and Boost.ASIO (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3562.pdf) My proposed Boost.AFIO library is an implementation of that same N3562 idea, albeit I extend Boost.ASIO which is IMHO more C++-y whereas Google and Microsoft have gone with proprietary implementations. Also, they include timing and many other more general purpose features, and mine does not (currently) as it's mainly aimed at maximising input/ouput with highly jittery random latency storage. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

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[heap] van Emde Boas tree
by Jeremy Murphy 07 May '13

07 May '13

Should I contact Tim Blechmann directly about the idea of adding a van Emde Boas tree to Boost.Heap, or is proposing it here the appropriate way to go about it? Thanks, cheers. Jeremy

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[any] Divergence between Boost.Any and standard library proposal
by Beman Dawes 07 May '13

07 May '13

A fresh draft of the proposal is up at http://beman.github.com/dot16/any-proposal.html In testing new any_cast examples, Boost.Any is handling one case differently from the proposal: any x; ... x = "Meow"; // x holds const char* This works fine with the Adobe implementation, but with the Boost implementation g++ 4.7.0 -std=c++11 reports: In file included from any_cast_test.cpp:5:0: c:\boost\trunk/boost/any.hpp: In instantiation of 'boost::any::holder<ValueType>::holder(c onst ValueType&) [with ValueType = char [5]]': c:\boost\trunk/boost/any.hpp:52:49: required from 'boost::any::any(const ValueType&) [wi th ValueType = char [5]]' c:\boost\trunk/boost/any.hpp:124:13: required from 'boost::any& boost::any::operator=(Va lueType&&) [with ValueType = const char (&)[5]; boost::any = boost::any]' any_cast_test.cpp:79:7: required from here c:\boost\trunk/boost/any.hpp:169:27: error: array used as initializer VC++ 2012 gets the same error, albeit with a much longer set of messages. AFAICS, the Adobe (and the proposed standard) behavior is preferred. The type does need to decay. Comments? --Beman

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[chrono/date] date conversion and arithmetic with unvalidated dates
by Vicente J. Botet Escriba 07 May '13

07 May '13

Hi, Note that N3344 suggest only day arithmetic for a day representation (which is always valid) and suggest only only a date representation. Could we apply arithmetic operations on a unvalidated date (without striving on UB)? e.g. day arithmetic on a ymd_date ymd_date d1(year(2013), may, day(66)); ymd_date d2 = d1 + day(1); If defined, which must be the value of d2? Could we convert a date representation to another one if the source date is unvalidated (without striving on UB)? e.g. ymd_date -> days_date ymd_date d1(year(2013), may, day(66)); days_date d2 = d1; If defined, which must be the value of d2? Best, Vicente

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[chrono/date] validated versus valid dates
by Vicente J. Botet Escriba 07 May '13

07 May '13

Hi, Allowing to build dates that are not validated doesn't mean that they are not valid. A validated date is always valid. E.g date d(year(2013), may, day(5)); d is not a validated date but is valid. Having a is_validated() function in addition to is_valid() could have its uses assert( ! d.is_validated() && d.is_valid() ); is_validated() function forces to use a bit to store this information on the date representation, but it improves the performances of the is_valid() function. Moving from a possible unvalidated to a validated one would need date d1; ... date d2(d1.year(), d1.month(), d1.day(), check); Instead of this a validate factory makes this clearer date d1; ... date d2 = validate(d1); date validate(date const& dt) { if (dt.is_validated()) return *this; else if (dt.is_valid()) { date res(dt); res.set_validated_(); // this is private return res; } throw bad_date(); } Best, Vicente

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Am I missing something or is Boost: String dictionary?
by david.hagood＠gmail.com 06 May '13

06 May '13

One of the libraries I work with (libXML2) has a very useful concept called a string dictionary, and I am surprised this doesn't appear to be in either STL or Boost. Am I missing something, or is Boost missing something? The basic idea is: Given you have a string and an instance of a dictionary, you can: 1) check if the string is already in the dictionary. 2) Add the string to the dictionary and return the dictionary entry (if the string is already present, return existing entry). The dictionary entries contain a copy of the string. Entries may be compared for equality/inequality in O(1) time. The lifespan of the strings in the entry is managed by the entry. This really simplifies writing parsers and the like, and is such a useful concept that I'm really surprised not to see it in STL or Boost.

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[GitHelp]github.com/boostorg/sandbox comment confusing
by Larry Evans 06 May '13

06 May '13

At: https://github.com/boostorg/sandbox there's a comment by Beman from 10 yrs ago saying: Removed as obsolete - use Boost.Random instead which makes no sense to me. Also, are any of the sandbox files from svn going to be moved to this github sandbox? TIA. -regards, Larry

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Fwd: GSOC:2013 Multiprecision Proposal Review
by Siddharth Jain 06 May '13

06 May '13

Please have a look at my proposal. The link to my proposal is http://www.google-melange.com/gsoc/proposal/review/google/gsoc2013/siddhart… and I have worked a lot on this proposal. Please suggest any changes which could be incorporated to improve this project. Regards Siddharth Jain

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Re: [boost] [gsoc-2013] Boost.Thread/ThreadPool project
by Niall Douglas 06 May '13

06 May '13

> Le 02/05/13 18:01, Niall Douglas a ?crit : > >> That's orthogonal. Boost.Asio provides the funding blocks. A nicer > >> interface that doesn't require an explicit continuation passing style > >> transformation can be built with Boost.Context or a similar library. > >> But it probably needs a future implementation that integrates with > >> ASIO, which is one of the point of Niall Douglas. > > Spot on. Especially as parts of ASIO are due to enter with TR2. I worry that > > a thread pool designed without ASIO in mind would become an orphan isolate. > What a ThreadPool must provide to satisfy the ASIO requirements? That's a very good question. And for me to answer in specifics I'd need to think deeply about the issue, and study examples, neither of which time currently allows given C++Now is just around the corner. All I can say right now - and I agree this isn't very helpful - is make it compatible with opaque third party event loop dispatchers such as Qt's QCoreApplication and QRunnable. Because Qt's implementation details iare opaque to external code, if you can meet compatibility with that you'll probably be compatible with anything Boost.ASIO can come up with, especially as most of Boost.ASIO is header defined. I appreciate that isn't very helpful. Thread pool design is hard :( Niall

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[config/multiprecision/units/general] Do we have a policy for user-defined-literals?
by John Maddock 06 May '13

06 May '13

Folks, I've been experimenting with the new C++11 feature "user-defined-literals", and they're pretty impressive ;-) So far I've been able to write code such as: auto i = 0x1234567890abcdef1234567890abcdef_cppi; and generate value i as a signed 128-bit integer. It's particulary remarkable because: * It actually works ;-) * The value is generated as a constexpr - all evaluation and initialization of the multiprecision integer is done at compile time. * The actual meta-code is remarkably short and concise once you've figured out how on earth to get started! Note however my code is limited to hexadecimal constants, because it can't do compile time radix conversion - that would require a huge meta-program for each constant :-( This is obviously useful to the multiprecision library, and I'm sure for Units as well, but that leaves a couple of questions: 1) We have no config macro for this new feature (I've only tested with GCC, and suspect Clang is the only other compiler with support at present). What should it be called? Would everyone be happy with BOOST_NO_CXX11_USER_DEFINED_LITERALS ? 2) How should libraries handle these user defined suffixes? The essencial problem is that they have to be in current scope at point of use, you can never explicitly qualify them. So I suggest we use: namespace boost{ namespace mylib{ namespace literals{ mytype operator "" _mysuffix(args...); }}} Then users can import the whole namespace easily into current scope right at point of use: int main() { using namespace boost::mylib::literals; boost::mylib::mytype t = 1234_mysuffix; } 3) How should the suffixes be named? There is an obvious possibility for clashes here - for example the units lib would probably want to use _s for seconds, but no doubt other users might use it for strings and such like. We could insist that all such names added to a boost lib are suitably mangled, so "_bu_s" for boost.units.seconds, but I'm not convinced by that. Seems to make the feature much less useful? Many thanks in advance for your thoughts, John.

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[chrono/date] Performance goals and design summary
by Vicente J. Botet Escriba 05 May '13

05 May '13

Hi, After the discussion on other threads I would like to summarize some of my performances goals while refactoring the H.H chrono/date library, just to see if I was wrong and going on the bad direction: 1. *Be able to build dates without validating them.* 2. *I wanted the library to be as efficient as possible when the user uses constant objects or literals, no need to validate at runtime what has already been validated by the compiler*. 3. *Possibility to reassign a date if the parameters represent a valid date.* 4. *No a single date class is better than the others on all the algorithms*. 5. *No additional meta-data in absolute dates so that you don't pay for the relative dates overhead when using absolute dates.* 6. *The user must be able to get all the date related informations at once.* Do you have other? The way I have managed with these goals is 1. *P*rovide an unchecked date construction interface with a no_check_t parameter and an is_valid() function. 2. *T*he date parts day/month/year need to be validated or constructed with no_check_t. 3. dt.set_if_valid(year, month, day) 4. Define the Date requirements all the dates must satisfy, implement ymd_date, days_date, ... 5. Separate the absolute and the relative Date requirements into two Date concepts AbsoluteDate and RelativeDate. Provide at least a relative_date class based on the ymd representation. 6. Conversion between different concrete date classe. H.H approach respond to these goals in a different way 1. date and its parts provide constructors that are not validated, the validation is provided by factories as operator/. 2. I don't think this can be achieved when the date must be validated. 3. No problem, this could be added to H.H approach (at least for its YMD date). 4. Same approach. H.H proposes two classes chrono::day_point (only unchecked) and YMD date. 5. I'm not sure the date YMD class doesn't include meta data (Howard could you clarify your point here) 6. same approach. I have some questions for followed by my personal answer; * *Do you see some unnecessary goals, in particular, is the goal 2**necessary?* IMO, yes. Not providing an interface that allows compiler optimizations is against the C++ philosophy. The question is as always, what would be the gain? In the best case we could avoid 6 comparisons. * *Does the introduction of no_check to achieve goal 1 and 2 results in a uglier date interface?* IMO, yes, but I don't know how to achieve goal 2 without. * *Should a concrete date class provide just the functionalities it is able to do efficiently?* IMO, yes. This would prevent the user of non efficient services (Note that my current design doesn't follows this) * *Do we need a Date concept that a concrete date must model**?* IMO, yes. SO we need two levels, level one provides the most efficient service, level two provides an homogeneous interface. * *Do we need to make the separation between absolute and relative dates?* IMO, yes. While relative dates are powerful they incur on unwanted overhead when absolute dates are needed. Best, Vicente

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[build] Conditional sources and compiler options
by Andrey Semashev 05 May '13

05 May '13

Hi, I'm trying to add some SIMD support to my library and I'm having problems with setting up my Jamfile properly. Basically, I have a number of source files that only need to be compiled when the compiler is of a specific version or later (say, gcc >= 4.7 or msvc >= 12 or intel >= X.Y on x86 but not for other compilers/architectures and not for older versions of the mentioned compilers). Next, I need to add special compiler options (specific for each compiler) just for these files. Natuarlly, I also have other source files that need not these tricks and should be compiled normally, without any special options. All source files have to be compiled into a single library (static or dynamic). Is there any way to do it in Boost.Build? I've read about alternatives in the docs, but they require duplicating the library target, which I'd like to avoid. I also read about conditional requirements, but as I understand they don't allow to specify version conditions (like <toolset>gcc >= 4.7). Also I didn't find any way to specify special build options for particular files. Thanks in advance.

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[boost.preprocessor.iteration] relative file iteration not supported
by Adrian H 05 May '13

05 May '13

Hello, I have used Boost in the past and do like the use of the preprocessor as a way of making repetitious code. However, I found that in a project that I was working on, I needed the ability to iterate over a file relative to the file I was iterating from, and that file wasn't relative to any of the include directories. I thought about this and it makes sense to why it didn't work, but I can see that it can prove to be inconvenient sometimes when someone wishes to make library header files relative to each other to allow for flexible positioning of the related files in the source tree or not have to add new items to the include directory set. I have written a preprocessor library to fill this need, but was wondering if such a library would be of interest to the Boost community. I deliberately tweaked it to be similar to the Boost Preprocessor Iterator library, and can be acquired at https://sourceforge.net/projects/relativeiterate/, including documentation and an example located in the README.txt file. I would appreciate any feedback you may have on this and would be more than willing to make changes to accommodate what would be needed for it to be included into the Boost set. Thank you for your time. Adrian -- ======================================== Adrian Hawryluk BSc. Computer Science ---------------------------------------- Specialising in: OOD Methodologies in UML OOP Methodologies in C, C++ and more RT Embedded Programming GUI Development ========================================

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[chrono/date] constructor, factories and validation
by Vicente J. Botet Escriba 05 May '13

05 May '13

Hi all, Two approaches to checking date validation have been proposed Howard approach: * date constructors build unchecked dates (provide the same order of parameters that the date factories. * date factories (expression using operator/()) build checked dates. * could be completed with make_date that will build checked dates. Advantages: * avoids the ugly no_check (that could be replaced by no_throw) Drawbacks * The 3 sets of date constructor factories must provide all the same order of parameters. * Creating a new factory will mean creating a new constructor on each concrete date class. * The factories must be friend of the concrete dates. My original approach complemented with make_date factory: * constructors without no_check build checked dates, and with no_check parameter build well unchecked ones. Provides only decreasing lexicographic order of arguments e.g. date(year,month,day), date(year,month,day,no_check_t). * make_date provides the usual combinations as provided by factory using operator/() and no_check. * date factories (expression using operator/()) build checked dates Advantages: * There are less date constructors. * We can add as many factories as we are able to construct with checking or not. Drawbacks * the no_throw/no_check/unchecked parameter is ugly and a source of conflict. Alternative approach (reverse the defaults): * constructors without check build unchecked dates, and with check parameter build well checked ones. Provides only decreasing lexicographic order of arguments e.g. date(year,month,day), date(year,month,day,check_t). * make_date provides the usual combinations as provided by factory using operator/() and check. * a make_checked_date could have also a sens. * date factories (expression using operator/()) build checked dates Best, Vicente

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