May 2012 - Boost - lists.preview.boost.org

[bind][phoenix] unified placeholders, yea or nay?
by Eric Niebler 29 May '12

29 May '12

I'm considering taking on as a side project the unification of the bind and phoenix placeholders, a perennial source of confusion and annoyance. I hesitate before beginning because it necessarily introduces some complexity into boost.bind, a very small, simple, and light-weight library. In particular, the unification would: 1) Cause boost.bind to depend on boost.proto. (I would do what I could to keep that dependency as slight as possible.) 2) Could not be supported on all platforms; e.g. not on borland or (gcc < 4) where the placeholders are actually static inline functions(!). (Peter, is this an ODR thing?) 3) Would introduce Phoenix behaviors into Bind, insofar as _1 is a lambda such that _1(42) evaluates to 42. At this point, it's not obvious to me that the benefits outweigh the costs. Opinions? Peter, I'd especially like to hear your thoughts. -- Eric Niebler BoostPro Computing http://www.boostpro.com

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Re: [boost] [Intrusive] Cleaning up trailing white space
by Brian Wood 29 May '12

29 May '12

Olaf van der Spek <ml(a)vdspek.org> On Thu, May 17, 2012 at 1:12 AM, Brian Wood <woodbrian77(a)gmail.com> wrote: >> >> This is probably the easiest way to improve Boost. ?I hope authors will > Really? Why? It can be done with a simple sed script and applied either to individual libraries or all of Boost. It's a small detail, but I hope it gets some attention. I brought it to Ion's attention as I use the Intrusive library and take a number of steps to reduce the need for new hardware. I won't stop using the library if he doesn't do this, but the squeaky wheel gets the oil. Cheers, Brian Ebenezer Enterprises http://webEbenezer.net <http://webebenezer.net/>

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[bind]bind question
by Max 28 May '12

28 May '12

Hi, I have the following code: bool do_something_conditional(int *handle, const boost::function<bool(int)> &pred); bool pred_a(int handle); bool pred_b(int handle, int n1, int n2); bool do_something(int *handle, int n1, int n2) { return do_something_conditional(handle, boost::bind(std::logical_and<bool>(), boost::not1(&pred_a), boost::bind(&pred_b, _1, n1, n2))); } But it does not compile. I have been not playing with bind stuff for some time. But I've reviewed the doc and some of my old 'bind' code, it seems correct to me. The error message, you know, is quite complicated for me to find a direct answer. Could anybody please help me? Thanks in advance. I'm using 1.39 with MS VS2008SP1 Best regards Max

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[GettingStarted] request for adding Boost.Chrono
by Vicente J. Botet Escriba 28 May '12

28 May '12

Hi, could Boost.Chrono be added to the list of libraries that need to be built in http://www.boost.org/doc/libs/1_49_0/more/getting_started/windows.html#head… Best, Vicente

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[io_base-utilities] Request for interest and/or comments.
by Vicente J. Botet Escriba 28 May '12

28 May '12

Hi, While refactoring the Boost.Chrono IO (version 2) I've created some utilities that could be of general use. * Manipulator Mixin It is is based on http://www.angelikalanger.com/Articles/Cuj/05.Manipulators/Manipulators.html. http://svn.boost.org/svn/boost/trunk/boost/chrono/io/utility/manip_base.hpp defines a class manip that can be used as follows class mendl: public manip<mendl> { public: explicit mendl(size_t how_many) : count(how_many) {} template <typename out_stream> void operator()(out_stream &out) const { for (size_t line = 0; line < count; ++line) { out.put(out.widen('\n')); } out.flush(); } private: size_t count; }; * std::ios_base Specific Pointers std::ios_base allows to create specific pointers indexed by xalloc() and retrieved by pword(). http://svn.boost.org/svn/boost/trunk/boost/chrono/io/utility/ios_base_state… defines a class ios_state_ptr class that provides the same interface that a smart ptr with some minor adaptations to a std::ios_base. template <typename Tag, typename T> class ios_state_ptr; The type T must be CopyConstructible. This class must be used as follows struct mytag {} struct myT { int i; }; ios_state_ptr<mytag, myT > ptr(ios); if (! ptr) { ptr.reset(new myT); } ptr->i =0; This class is not thread_safe and should be protected as other io functions if the user needs to use them in a multi-threaded environment; The user can use also ios_state_ptr for classes T that are DefaultConstructible, so that the type is created implicitly if not already created. ios_state_not_null_ptr<mytag, myT > ptr(ios); ptr->i =0; This class is not thread_safe. Boost.Chrono use it as follows namespace chrono { namespace detail { template<typename CharT> struct ios_base_data_aux { std::basic_string<CharT> time_fmt; std::basic_string<CharT> duration_fmt; public: ios_base_data_aux() : time_fmt(""), duration_fmt("") {} }; template<typename CharT> struct ios_base_data {}; } // namespace detail template<typename CharT> static inline std::basic_string<CharT> get_time_fmt(std::ios_base & ios) { ios_state_not_null_ptr<detail::ios_base_data<CharT>, detail::ios_base_data_aux<CharT> > ptr(ios); return ptr->time_fmt; } template<typename CharT> static inline void set_time_fmt(std::ios_base& ios, std::basic_string< CharT> const& fmt) { ios_state_not_null_ptr<detail::ios_base_data<CharT>, detail::ios_base_data_aux<CharT> > ptr(ios); ptr->time_fmt = fmt; } } The internal single call to xalloc should be done before main() to be thread safe. The library provide a initializer class xalloc_key_initializer that takes as parameter a tag class. namespace chrono { namespace detail { namespace /**/ { xalloc_key_initializer<detail::ios_base_data<char> > ios_base_data_aux_xalloc_key_initializer; xalloc_key_initializer<detail::ios_base_data<wchar_t> > wios_base_data_aux_xalloc_key_initializer; #if BOOST_CHRONO_HAS_UNICODE_SUPPORT xalloc_key_initializer<detail::ios_base_data<char16_t> > u16ios_base_data_aux_xalloc_key_initializer; xalloc_key_initializer<detail::ios_base_data<char32_t> > u32ios_base_data_aux_xalloc_key_initializer; #endif } // namespace } } * ios_flags ios_base allows also to create specific pointers indexed by xalloc() and retrieved by iword(). http://svn.boost.org/svn/boost/trunk/boost/chrono/io/utility/ios_base_state… defines a class template <typename Final> class ios_flags; providing an interface similar to "27.5.3.2 ios_base state functions [fmtflags.state] fmtflags flags() const; Returns: The format control information for both input and output. fmtflags flags(fmtflags fmtfl); Postcondition: fmtfl == flags(). Returns: The previous value of flags(). fmtflags setf(fmtflags fmtfl); Effects: Sets fmtfl in flags(). Returns: The previous value of flags(). fmtflags setf(fmtflags fmtfl, fmtflags mask); Effects: Clears mask in flags(), sets fmtfl & mask in flags(). Returns: The previous value of flags(). void unsetf(fmtflags mask); Effects: Clears mask in flags() " and that creates implicitly the index of the ios_base::iword() function once for a specific ios_flags<Final>. For example, Boost.Chrono use it as follows to store the use_symbol and use_local flags. class fmt_masks : public ios_flags<fmt_masks> { typedef ios_flags<fmt_masks> base_type; public: fmt_masks(std::ios_base& ios): base_type(ios) {} enum type { uses_symbol = 1 << 0, uses_local = 1 << 1 }; duration_style get_duration_style() { return (flags() & uses_symbol) ? duration_style::symbol : duration_style::prefix; } void set_duration_style(duration_style style) { if (style == duration_style::symbol) setf(uses_symbol); else unsetf(uses_symbol); } timezone get_timezone() { return (flags() & uses_local) ? timezone::local : timezone::utc; } void set_timezone(timezone tz) { if (tz == timezone::local) setf(uses_local); else unsetf(uses_local); } }; The internal single call to xalloc should be done before main() to be thread safe. The library provide a initializer class namespace detail { namespace /**/ { xalloc_key_initializer<fmt_masks > fmt_masks_xalloc_key_initializer; } // namespace } // namespace detail Do you see a design flaw on the design of these classes? Is there an interest to include them in Boost? Could these classes be associated iostreams? Best, Vicente

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Sophisticated Email Virus
by Richard Scott 28 May '12

28 May '12

Good Afternoon All, Early this morning, I was the victim of a email virus which may have captured your email address from my address book. Hopefully, my antivirus software prevented that. If you receive a very terse but generally plausible message from me exhorting you to open an unnamed web site link, DO NOT open that link. This message might be transmitted from a third site using my email address. It will attempt to capture your email addresses and possibly information of an unknown sort and retransmit it to a third site for subsequent use. This could happen either immediately or months from now. For my part, my messages are generally not overly short or cryptic and I generally employ named links. Richard Scott

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[1.50] [Config] Enhancing support of -fno-rtti on clang
by Michel Morin 27 May '12

27 May '12

When using clang with -fno-rtti, the use of `typeid` results in either compile-time errors or run-time errors. But Boost.Config did not define BOOST_NO_TYPEID for that case. So, for example, including any client header of BOOST_SP_TYPEID produced compiler errors on clang trunk with -fno-rtti. This was fixed in r78510 about a week ago: (http://svn.boost.org/trac/boost/changeset/78510) -#if !__has_feature(cxx_rtti) +#if !__has_feature(cxx_rtti) && !defined(BOOST_NO_RTTI) # define BOOST_NO_RTTI #endif +#if !__has_feature(cxx_rtti) && !defined(BOOST_NO_TYPEID) +# define BOOST_NO_TYPEID +#endif If Boost would like to enhance the support of -fno-rtti on clang, it would be good to merge the fix into the release branch. I ran the test runner (clang trunk with -fno-rtti) for unpatched release branch and patched release branch. There was no regression and more than 1000 test results got improved. Regards, Michel

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[pimpl] links
by Vicente J. Botet Escriba 26 May '12

26 May '12

Hi, where can I get the source and documentation for the proposed Boost.PImpl? The doc link points to a paper and the source link points to github. Best, Vicente

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Schedule link broken for multiprecision doc
by Vicente J. Botet Escriba 26 May '12

26 May '12

Hi, the link http://svn.boost.org/svn/boost/sandbox/big_number/libs/multiprecision/doc/h…. is broken. Best, Vicente

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committing patches to other libraries (was [1.50.0] Beta schedule)
by Jeffrey Lee Hellrung, Jr. 26 May '12

26 May '12

:: bump :: On Tue, May 22, 2012 at 11:13 AM, Jeffrey Lee Hellrung, Jr. < jeffrey.hellrung(a)gmail.com> wrote: > On Tue, May 22, 2012 at 5:46 AM, Beman Dawes <bdawes(a)acm.org> wrote: > >> C++Now! is history, so it is high time to get the 1.50.0 beta out the >> door. >> >> Branches/release is now closed for all changes except by permission >> from a release manager. >> > > Request to merge > > https://svn.boost.org/trac/boost/changeset/78501 > > which just takes care of a shadowing warning on gcc. > > Couple things: > (a) I just went ahead and made this change on trunk a few days ago because > I stumbled into this warning myself, searched track, and saw that it was > already reported and had a patch (indirectly) attached; in retrospect, I > apologize if I stepped on anyone's (Jeremy's?) toes, and so I ask: Is there > a formal or informal protocol for applying relatively simple patches like > this one? > (b) Along the same lines, assuming permission is granted and given (a), > should I be merging this to release, or should that fall to the library > maintainer? > > Thanks, > > - Jeff > I was hoping to get some direction regarding the above before continuing to; specifically, what should be done about this particular changeset, and some guidelines for similar situations in the future. (I am aware of the recently revised release schedule, so disregard the "request to merge" in that context.) Thanks, - Jeff

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[range] Will Boost.Range be merged
by Barend Gehrels 26 May '12

26 May '12

Hi, Will Boost.Range (including the change of boost::size from signed to unsigned) be merged into release? Regards, Barend

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[python] incorrect use of keywords and, or, etc
by lcaminiti 25 May '12

25 May '12

Hello all, Boost.Python uses operator keywords in macro expansion. This is a bad idea because on some compilers like MSVC that implement and, or, etc using macros #define to &&, ||, these macros will not expand correctly when ciso646 is included before including python.hpp. #include <ciso646> // boost/python/operators.hpp BOOST_PYTHON_BINARY_OPERATOR(and, rand, &) BOOST_PYTHON_BINARY_OPERATOR(or, ror, |) ... This will actually expand to: BOOST_PYTHON_BINARY_OPERATOR(&&, rand, &) BOOST_PYTHON_BINARY_OPERATOR(||, ror, |) And then expand the macro causing a compiler error because the operator code will have names like op_&&, op_||, etc instead of the intended op_and, op_or, etc. An easy and safe fix should be to change the macro to move the _ to the macro call: BOOST_PYTHON_BINARY_OPERATOR(_and, rand, &) BOOST_PYTHON_BINARY_OPERATOR(_or, ror, |) Now _and, _or, etc are no longer keywords so it's safe to use them. --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-python-incorrect-use-of-keywords-a… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[range] Boost.Range induced regression, is there somewhere a change?
by Barend Gehrels 25 May '12

25 May '12

Hi, Is there something changed in Boost.Range? Background: I just noticed that there appeared many failing issues (yellow squares) in the Boost.Geometry regression matrix here: http://www.boost.org/development/tests/trunk/developer/geometry.html I checked the assemble square and it gives me an assertion: Assertion `id.ring_index >= -1 && id.ring_index < boost::size(interior_rings(polygon))' Because this did not use to be the case, I did run the test on my local machine and it was OK. Then I updated some Boost libraries (manually, separately) and as soon as I updated Boost.Range this exception did appear. So the regression is somehow caused by a change in Boost.Range. I did not yet research it further, it might be that we do something wrong here that was previously accepted but now is not, but it still stays an unexpected regression... Is there someone who has any idea what introduced this? Thanks, Barend

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C++ Standards Committee membership for Boost?
by Beman Dawes 25 May '12

25 May '12

The relationship between Boost and the C++ Standards Committee has been strictly informal. That's been fine, particularly given that most Boost moderators were members of the standards committee and regularly attended meetings. As the standards committee gears up to accept library proposals, the relationship is getting even closer. I believe it would be advantageous for Boost to join the C++ committee as a voting member. Procedurally, that would mean joining the INCITS (www.incits.org) PL22.16, which is the US national body for C++ standardization. Boost is consider US domiciled in ISO-speak. The advantages of joining include: * We get to participate in formal votes. Right now, we only participate in straw votes. * Boosters would be able to attend committee meetings by right rather than as a courtesy. * Boosters would be able to participate in committee mailing lists with less hoops to jump through. * Psychologically, it may give us a bit more weight in committee matters. Comments? Opinions? --Beman

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regression tests fail with no error?
by lcaminiti 24 May '12

24 May '12

Hello all, Some of my library regression tests occasionally fail like this: http://www.boost.org/development/tests/release/developer/Sandia-darwin-inte… If you follow the link, there is no actual error. Plus the tests sometimes it fails (with no actual error) and other times it passes (as it should). Is this just a problem with the regression test parsing script? Thanks a lot. --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-regression-tests-fail-with-no-erro… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[1.50.0] Beta schedule
by Beman Dawes 24 May '12

24 May '12

C++Now! is history, so it is high time to get the 1.50.0 beta out the door. Branches/release is now closed for all changes except by permission from a release manager. Unless there are strong objections, I suggest we close branches\release for all changes next Monday, May 28, and ship the beta release as soon after that as a RC can be built and tested. I'm about to post a separate message discussing the length of beta periods. --Beman

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[MSM] Single event, multiple orthogonal submachines
by Andrew Hundt 23 May '12

23 May '12

I'm trying to deal with having multiple orthogonal submachines that process one event containing data. I have a contrived example that hopefully conveys the issue. Suppose I am hoping to create a state machine "Game2D" with a set of orthogonal submachines that guard certain transitions based on each other, and I would like some events to be processed by multiple submachines. Parent Machine: Game2D Event: CharacterStatus - contains character position and velocity Submachines: IsMoving - changes state based on CharacterStatus CorrectPosition - updates position based on CharacterStatus CharacterStatusUpToDate - times out to an error state if CharacterStatus hasn't been received for a while EnemyAlive - doesn't process CharacterStatus RunSystem - guards some transitions based on the state of IsMoving Since some, but not all of these submachines needs the "CharacterStatus" event, what is the best way to make sure they all get it when I call Game2D.process_event(CharacterStatus)? I want to be able to reuse these pieces, and keep things as simple as possible. Does this seem like an ok approach? Should I simply have a state "UpdateCharacterStatus" that directly updates each of these objects then creates an event to transition away, or something else entirely? Cheers! Andrew Hundt

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Release schedule related updates
by Beman Dawes 23 May '12

23 May '12

https://svn.boost.org/trac/boost/wiki/ReleaseSchedule has been updated to reflect experience and lengthen the beta period. https://svn.boost.org/trac/boost/wiki/ReleasePractices/ManagerCheckList has been updated to reflect the importance of the calendar. The Google calendar itself has been updated for releases 1.50.0, 1.51.0, and 1.52.0. I'm looking into ways to queue postings of release milestones so they get sent automatically and don't get forgotten. Thanks, --Beman

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[ot] choosing a build system
by Nathan Ridge 23 May '12

23 May '12

Hello, I am developing a new C++ library (unrelated to Boost) and I need to choose a build system for it. I had originally planned to use Boost.Build, because I figured that it would be particularly suitable for a C++ library, and because I've come to associate Boost with high quality and excellence. However, recently I've heard talk of Boost switching its own build system from Boost.Build to CMake (in fact, the currently active thread about modularization suggests that this change is imminent). My understanding is that Boost is the primary user of Boost.Build, and therefore I am concerned about what this switch means for the future of Boost.Build. Do you think choosing Boost.Build as the build system for a project is still a sound choice, or am I better off choosing something else like CMake? More generally, what build system would you recommend for a C++ library? My requirements for the build system are the following: - straightforward support for multiple variants of the build (32-bit vs. 64-bit, debug vs. release, static vs. shared, etc.), including coexistence of multiple variants on the same machine - general ease of use (for the library writer and library users) - suitability for a C++ project - cross-platform, FOSS Any thoughts are appreciated. Thanks, Nate

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spirit classic modularization
by Dave Abrahams 22 May '12

22 May '12

While I was in Aspen I split Spirit and Spirit Classic into separate Git repositories: https://github.com/boost-lib/spirit https://github.com/boost-lib/spirit_classic The manifest entries begin here, and as you can see, are quite long for these two libraries: https://github.com/ryppl/boost-modularize/blob/master/manifest.txt#L643 This is mostly due to the limited expressivity of the manifest language, but regardless... The question, for Spirit developers: which arrangement is better? Should both spirits go back into a single repository? -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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[test] mingw 4.5, 4.6, compile failure with trunk
by Beman Dawes 22 May '12

22 May '12

..\..\../boost/test/utils/runtime/config.hpp: In function 'void boost::runtime::putenv_impl(boost::runtime::cstring, boost::runtime::cstring)': ..\..\../boost/test/utils/runtime/config.hpp:95:51: error: 'putenv' was not declared in this scope This is preventing me from testing other Boost libraries that use Boost.Test:-( --Beman

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[releases] How long between beta and final release?
by Beman Dawes 22 May '12

22 May '12

Although there has been general agreement that there should be more time between beta and final releases, we haven't nailed down the exact duration. To get discussion started, I'll propose five weeks as the target time between beta and final release. Since there needs to be a week for final regression tests to cycle and release candidates to be tested, that would allow four weeks for beta fixes to be incorporated. Comments? --Beman

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Using Boost with IBM Rhapsody and UML?
by David Hagood 22 May '12

22 May '12

Does anybody have experience pulling Boost into IBM's Rhapsody UML tool, such that Rhapsody will be able to use Boost in UML models and UML to C++ codegen?

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[decimal] Proposed portable implementation ofstd::decimal
by Josh Quigley 22 May '12

22 May '12

Hi all. A first draft of this library is available at https://sourceforge.net/projects/stddecimal/ Runs on MSVC10 and gcc 4.6.3. Wraps the Intel implementation only, Until we resolve the licencing issue, top-level README contains detailed instructions about where to get 3rd party code and what to do with it. I'm keen on feedback on a particular point (although all feedback is of course welcome!): The current project can parse and execute the test cases maintained by Mike Cowlishaw from http://speleotrove.com/decimal/ (referred to as the Test Cases). To be completely clear, I also have normal, interface testing test cases, I am *not* talking about those below. - Question: How useful do people feel the Test Cases to be? I originally expected 99% of these tests to pass, but it turns out that most of them require: - The operands to be parsed and stored at the precision they appear in the Test Case file - The operation to be performed at precision of the operands - The high precision result to be rounded to the precision required by the Test Cases. - The test inputs to be parsed with correct rounding in underflow situations (not required by IEEE afaik) The above requirements are based on my experience with the tests - it is possible I'm making a blunder somewhere. Since the Test Cases are really testing the 3rd party library, an argument could be made they are not essential, or even desirable. I'm inclined to think they would be very, very nice to have, as they would give users a lot of confidence - I suspect user uptake would be poor without this confidence. So... what do people think? Regards, Josh. (PS gmail seems to be confused about who 'boost' is, so apologies for the cross-posts!)

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Re: [boost] Boost Modularization: did we get it right?
by Oliver Kowalke 21 May '12

21 May '12

The headers are moved into directory'include' - how does the build system handle includes (header from other boost libs)? At least I get error that header xyz is not found if I execute the tests using bjam. Oliver -- Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir belohnen Sie mit bis zu 50,- Euro! https://freundschaftswerbung.gmx.de

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