October 2014 - Boost - lists.preview.boost.org

Submodules of Boost libraries
by Mathias Gaunard 07 Oct '14

07 Oct '14

Hi folks, I'd like to ready my library for inclusion into Boost. My library is made of several modules, and I'd like to keep that into Boost. How does Boost handles multiple submodules within a library submodule?

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[modularization] LocalFunction and ScopedExit cycle
by Vicente J. Botet Escriba 06 Oct '14

06 Oct '14

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[move] Macro for initializing base classes in move ctors.
by Mostafa 04 Oct '14

04 Oct '14

Initializing base classes in move constructors involves some boiler-plate code. Is there a reason why a macro is not provided for it? Something like: #define BOOST_MOVE_INITBASEMOVECTOR(baseclassname, rhs) \ baseclassname(::boost::move(static_cast<baseclassname &>(rhs)))

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[mpl] struct definition and mpl sequence in one shot?
by Adam Romanek 03 Oct '14

03 Oct '14

Hi! This is a re-post from the boost-users mailing list. I have a problem and I'm not sure how to approach it. Currently my code looks like this: struct Definition { typedef boost::mpl::int_<5> A; typedef boost::mpl::int_<3> B; typedef boost::mpl::int_<6> C; typedef boost::mpl::int_<1> D; typedef boost::mpl::vector<A, B, C, D> Seq; }; Here, the number N in mpl::int_< N > denotes some arbitrary decimal number. Then some other code calculates the sum of these numbers up to the type defined by "key", e.g. for Definition::D, the sum is 5 + 3 + 6 (A + B + C). This needs to be done at compile-time. That's why I use mpl::vector and some appropriate meta-programming. I'm wondering whether it would be possible to provide such struct definition without the need to repeat type names in the mpl::vector for Seq type. In other words, I'd probably need a bunch of macros which would allow me to write code like this: struct Definition { FIELD(A, 5); FIELD(B, 3); FIELD(C, 6); FIELD(D, 1); GEN_SEQ() // if needed }; And then Definition::A would still refer to boost::mpl::int_<5>, or would at least allow me to access the boost::mpl::int_<5> somehow, and Definition::Seq would give me the appropriate MPL sequence. Of couse this is just my imagination. The code might look different, I'm just looking for options. Thanks in advance. Adam Romanek

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[Boost] [DateTime] dividing a time_period in N time_periods
by Pablo Madoery 02 Oct '14

02 Oct '14

Hi, I want to make a method which divides a time_period in N time periods, something like this: list<time_period> splitTimePeriod(time_period timePeriod, int n); I actually have made it and although it seems to work it results very inefficient regarding the time it took to divide a large time_period. The method I did is this: list<time_period> splitTimePeriod(time_period timePeriod, int n) { double secsTime = dateTime::diffSeconds(timePeriod.end(), timePeriod.begin()); // tiempo en segundos de cada período de tiempo double ti = secsTime / n; list<time_period> timePeriods; // tiempo de comienzo del primer período de tiempo ptime tpBegin = timePeriod.begin(); // tiempo de fin del último período de tiempo ptime tpLastEnd = timePeriod.end(); for (int i = 0; i < n; i++) { int tUnits = ti * time_duration::ticks_per_second(); // tiempo de comienzo del siguiente período de tiempo ptime tpNextBegin = dateTime::increment(tpBegin, tUnits); // tiempo de fin del período de tiempo ptime tpEnd; if (i == n - 1) { tpEnd = tpLastEnd; } else { tpEnd = dateTime::decrement(tpNextBegin, 1); // guarda para evitar que por cuestiones // de redondeo, el tiempo final de un período // sea mayor que el pasado inicialmente // como argumento de entrada if (tpEnd > tpLastEnd) { tpEnd = tpLastEnd; } } time_period p(tpBegin, tpEnd); // se inserta período de tiempo en la lista timePeriods.push_back(p); // se actualiza el comienzo del siguiente período de tiempo tpBegin = tpNextBegin; } return timePeriods; } Other methods I use are these: double diffSeconds(const ptime &dateA, const ptime &dateB) { time_duration diff = dateA - dateB; return diff.total_seconds(); } ptime increment(const ptime &date, int n) { time_iterator it(date, dateTime::unit); for (int i = 0; i < n; i++) { ++it; } return *it; } ptime decrement(const ptime &date, int n) { time_iterator it(date, dateTime::unit); for (int i = 0; i < n; i++) { --it; } return *it; } const time_duration unit = microseconds(1); ################################################# The question is: is there a better way to accomplish this?

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[static_if] Is there interest in a `static if` emulation library?
by Lorenzo Caminiti 01 Oct '14

01 Oct '14

Hello all, With C++14 generic lambdas, it is possible to implement a sort of `static if` (see also N3613): template< typename T > void assign ( T& x, T const& y ) { x = y; static_if<boost::has_equal_to<T>::value>( std::bind([] ( auto x, auto y ) { assert(x == y); std::cout << "asserted for: " << typeid(T).name() << std::endl; }, x, y) ).else_( [] ( ) { std::cout << "cannot assert for: " << typeid(T).name() << std::endl; } ); } The bind around the generic lambda is a bit verbose... but this code compiles, asserts when called on int, and does not assert when called on x_t (tested on clang 3.4.2): int i = 1; struct x_t { } x; assign(i, i); // asserts assign(x, x); // does not assert I have attached a reference implementation. Thank you. --Lorenzo P.S. I didn't do much background research... sorry if this topic has already been considered and discussed in Boost.

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[uuid] Issue 9407: help required to merge fix
by Antony Polukhin 01 Oct '14

01 Oct '14

There is an issue with long history https://svn.boost.org/trac/boost/ticket/9407 That issue is annoying and can be easily fixed. There's even a pull request to fix that issue (https://github.com/boostorg/uuid/pull/2). Could someone take a look at the pull request, comment it and even merge to develop branch? -- Best regards, Antony Polukhin

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Licensing issue (TestCmd.py)
by Polhodzik Peter (ext) 01 Oct '14

01 Oct '14

Hi all, Could anyone tell me, why the \boost_1_38_0\tools\build\v2\test\TestCmd.py (TestCmd version 0.02) file in Boost 1.38.0<http://www.boost.org/users/history/version_1_38_0.html> has Steven Knight's Python license reference, this: # Copyright 2000 Steven Knight # This module is free software, and you may redistribute it and/or modify # it under the same terms as Python itself, so long as this copyright message # and disclaimer are retained in their original form. # # IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, # SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF # THIS CODE, EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH # DAMAGE. # # THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A # PARTICULAR PURPOSE. THE CODE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, # AND THERE IS NO OBLIGATION WHATSOEVER TO PROVIDE MAINTENANCE, # SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. __author__ = "Steven Knight <knight(a)baldmt.com<mailto:knight@baldmt.com>>" __revision__ = "TestCmd.py 0.D002 2001/08/31 14:56:12 software" __version__ = "0.02" while the original TestCmd 0.02<http://baldmt.com/Test-Cmd/Archive/Test-Cmd-0.02.tar.gz> is Perl licensed, this way: COPYRIGHT Copyright 1999-2000 Steven Knight. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. ? It is also unclear which Python or Perl license it refers to ,since there are more licenses versions for both. I know 1.38.0 is an old release, but now I definitely need to have the information about this one. Updating to 1.56.0 is NOT an option to solve the problem this time. Thank you!! Üdvözlettel / Best Regards, Péter POLHODZIK OSS Expert [cid:image001.jpg@01CFDD70.90958F30] Phone: +36 (46) 5-17894 Fax: +36 (46) 5-17801 Peter.Polhodzik.ext(a)evosoft.com<mailto:Peter.Polhodzik.ext@evosoft.com> evosoft Hungary Kft. Arany János tér 1. H-3508 Miskolc www.evosoft.com<http://www.evosoft.com/> ---------------------------------------------------

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[move] Build failures in develop
by Andrey Semashev 01 Oct '14

01 Oct '14

Hi, I'm seeing lots of build errors that originate from Boost.Move, such as: In file included from ../libs/log/src/text_file_backend.cpp:41: In file included from ../boost/filesystem/path.hpp:28: In file included from ../boost/iterator/iterator_facade.hpp:12: In file included from ../boost/iterator/interoperable.hpp:11: In file included from ../boost/mpl/or.hpp:23: ../boost/mpl/aux_/nested_type_wknd.hpp:27:10: error: no type named 'type' in 'boost::move_detail::is_rv<boost::rv<boost::log::v2_mt_posix::aux::light_function<void ()> > >' : T::type ~~~^~~~ See the full error logs: http://www.boost.org/development/tests/develop/developer/output/marshall-ma… http://www.boost.org/development/tests/develop/developer/output/teeks99-08b… http://www.boost.org/development/tests/develop/developer/output/teeks99-tes… I didn't change Boost.Log for quite some time, so there seems to have been some breaking change. Could this be fixed?

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[thread] Build failures in develop
by Andrey Semashev 01 Oct '14

01 Oct '14

Hi, Boost.Thread currently fails to build on MSVC, which affects other libraries: http://www.boost.org/development/tests/develop/developer/output/teeks99-08d… Could it be fixed?

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