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

The master branch is now open for merging
by Marshall Clow 20 Oct '14

20 Oct '14

Please limit to changes that have been implemented in develop and whose tests have cycled. We will be closing the master branch again sometime next week (for the final release two weeks from today). The following problems were noted with the RC (and, I believe, have fixes ready): * Interprocess is broken for MinGW * Visual C++ 14 CTP 4 without BOOST_MSVC_ENABLE_2014_JUN_CTP * For MSVC14, TypeTraits 9de6a49 is missing in master * Thread fixes from Vicente Still needed to do: * Can someone take a look at http://lists.boost.org/Archives/boost/2014/10/217257.php, please? * MSVC 8.0 compilation failures * range/detail/any_iterator.hpp is broken because it expects postfix_increment_proxy and writable_postfix_increment_proxy to be in namespace boost::detail, but they are in boost::iterators::detail now. * There’s a few old Random fixes that need to be looked at. (and anything else we find) Thanks to everyone who tried out the RC, and please encourage people to try the beta! — Marshall

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Re: [boost] [Boost-users] 1.57.0 beta 1 release candidates available for testing
by Marshall Clow 20 Oct '14

20 Oct '14

On Oct 20, 2014, at 7:06 AM, Marcel Raad <raad(a)teamviewer.com> wrote: > Marshall Clow <mclow.lists <at> gmail.com> writes: > >> Release candidate files for 1.57.0 beta 1 are available [...] >> As always, the release managers would appreciate it if you download the >> candidate of your choice and give building it a try. Please report both >> success and failure, and anything else that is noteworthy. > > range/detail/any_iterator.hpp is broken because it expects > postfix_increment_proxy and writable_postfix_increment_proxy to be in > namespace boost::detail, but they are in boost::iterators::detail now. > > Those errors are also visible in all of the type_erased_* regression tests > of range. I made an executive decision to push the beta out with this problem (and the MSVC 8.0 bugs, too), because I wanted to get a wider audience looking at the beta. Thanks for reporting this, and now let’s fix them. — Marshall

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[intrusive] More features for treap?
by Phil Endecott 20 Oct '14

20 Oct '14

Dear All, I've been looking at Boost.Intrusive's treap, and finding that it doesn't quite do what I need. Here's an example: say I have data about earthquakes in the form (date, magnitude, description). I can store that in a treap with date as the key and magnitude as the priority. Now I'd like to be able to do operations like: - Find the strongest earthquake between dates A and B. - Iterate over all the earthquakes with magnitude > X in date order. - For each year (or month, or decade etc) find the strongest quake. The first two are straightforward in a treap, but the current Boost.Intrusive API doesn't (AFAICT) let me do it. (The third one is less obvious.) I have been wondering how the API could most easily be extended to support this sort of thing, and I'm coming to the conclusion that it is probably best to expose the actual tree structure so that the algorithms for these operations can be implemented explicitly by the user code. I have had similar thoughts in the past about other trees i.e. augmented trees to implement interval trees; the choice is either (a) implement these things inside Boost.Intrusive; (b) don't use Boost.Intrusive at all; (c) extend the intrusive API to expose the actual tree structure. In cases like these extensions to treap, the new operations are simple compared to the complexities of inserting and erasing elements; being able to use the existing implementations of those operations while adding other (non-mutating?) features would save a lot of work. Any thoughts anyone? (Is anyone else using treap?) Regards, Phil.

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[random] Any news?
by Marco Guazzone 20 Oct '14

20 Oct '14

Hello, Do you have any news on lib mainteners? I and other have pull requests But all seems muted.

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Re: [boost] [Boost-users] 1.57.0 beta 1 release candidates available for testing
by Marshall Clow 20 Oct '14

20 Oct '14

On Oct 20, 2014, at 3:52 AM, John Maddock <boost.regex(a)virgin.net> wrote: >>> For Boost.Config: >>> >>> a mostly minor update. >> >> Great, thanks! According to the feature table, auto return types >> (BOOST_NO_CXX14_RETURN_TYPE_DEDUCTION) are also supported. > > Confirmed - it passes our test case anyway, feature enabled. > >>> For TypeTraits: >>> >>> I suspect you're not going to like the latter as it basically disables >>> working versions of is_nothrow* for msvc-14. The reason is that is >>> appears that Boost.Log ends up using noexcept(non_compiling_expression) >>> which requires SFINAE expression support. >> >> I also think it's the best solution. You can also delete >> the "!::boost::is_const<T>::value" with it now. > > Done. > > Marshall - is it OK to merge these fixes after the beta is out? Absolutely. — Marshall

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1.57.0 beta 1 release candidates available for testing
by Marshall Clow 20 Oct '14

20 Oct '14

Release candidate files for 1.57.0 beta 1 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: MD5 (boost_1_57_0_b1_rc1.7z) = 8633fbf5ebb7eaabcb0f309c14646ae3 MD5 (boost_1_57_0_b1_rc1.tar.bz2) = 8e76f98146793f0fbd2492a9151c405b MD5 (boost_1_57_0_b1_rc1.tar.gz) = d41ff3ffb36ac84ff5bf34f799308907 MD5 (boost_1_57_0_b1_rc1.zip) = 8a844dc36284247b2e936f2120e118b2 Thanks! -- The release managers

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Re: [boost] [Boost-users] 1.57.0 beta 1 release candidates available for testing
by Marshall Clow 20 Oct '14

20 Oct '14

On Oct 19, 2014, at 2:22 PM, Vicente J. Botet Escriba <vicente.botet(a)wanadoo.fr> wrote: > Le 18/10/14 00:40, Marshall Clow a écrit : >> Release candidate files for 1.57.0 beta 1 are available at >> http://boost.cowic.de/rc/ >> >> > Hi, could I merge the following to the master branch? > > https://github.com/boostorg/thread/commit/3e28ea806c412c697f134fdaacbccc9b6… > https://github.com/boostorg/thread/commit/1029fa9c5937269c9a65848972da7d8bb… > https://github.com/boostorg/thread/commit/63dd439992cbc6d62f0af442f4669121e… > > > This fixes "deferred/ready futures on variadic when_all/when_any.” Vicente — I’d appreciate if you would merge those *after* we release the beta. There will be about a week where the master branch will be open again. — Marshall (who would like to get the beta out to a wide audience sooner, rather than later)

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Performance characteristics of Boost mutex
by Philip Bennefall 18 Oct '14

18 Oct '14

Hi all, I am detecting some lock contention in my application, and while reading up on this I came across the concept of lightweight mutexes versus supposedly non-lightweight mutexes. I am wondering, can Boosts non-recursive mutex implementation be considered lightweight? In boost/detail I see lightweight_mutex. Should I be using that? I need no interprocess support here, and I want the lock to be as fast as possible. If I do decide to use lightweight_mutex, is it compatible with the regular non-recursive Boost mutex so that I can use it with higher level classes like lock guard, condition variables, barriers etc? Thanks in advance for any insight. Kind regards, Philip Bennefall

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Re: [boost] [asio] RFC on new reliable UDP library
by Niall Douglas 17 Oct '14

17 Oct '14

On 17 Oct 2014 at 10:54, Juan Carlos Franzoy wrote: > > A long term dream of mine is for ASIO to become the standard event > > dispatch loop for all C++ programs, so other libraries simply hook > > into ASIO's dispatch and everything interoperates cleanly without > > lots of hassle and brittle boilerplate. I also feel a grievance > > against every single library firing up their own thread pools or > > worker threads when ASIO gives you that for free. > > We tried to use ASIO as an event dispatch, but it failed to scale in > multicore machines. Currently we are experimenting using one io_service > per core and manually managing the load balance migrating sockets between > io_services. If this is on Linux, then yes I have found this too. ASIO uses std::mutex as its lock, and the spin count on pthread_mutex in glibc is too short for modern CPUs. My proposed concurrent_unordered_map, which can do safe concurrent erase, would solve the need for ASIO needing a central mutex on Linux. > Maybe ASIO has to manage only io (only io threads) and has to delegate > to an external thread pool the execution of user handlers. Although I > don't know if it is technically possible. ASIO's present design is suboptimal in many regards. It's one of my biggest qualms in the present design being standardised as-is. I may, six months from now, be able to say in considerable detail what exactly to change if things pan out. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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Ticketspam
by Daniel Frey 17 Oct '14

17 Oct '14

One more to remove: <https://svn.boost.org/trac/boost/ticket/10560> Thanks, Daniel

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NT² eand Boost.SIMD release 3.1
by Joel FALCOU 17 Oct '14

17 Oct '14

NT2 is a Matlab inspired, high-level API for scientific computation in C++. Boost.SIMD is a candidate library for inclusion in Boost dealing with the portable encpsulation of SIMD instructions sets. This following releases updates NT2 and Boost.SIMD libraries to version 3.1 This new release of NT2 and Boost.SIMD focused on fixing performance issues and add some new support for architecture and parallel algorithms. The main new features include: - Linear Algebra functions can now use GPGPU through the MAGMA library whenever possible. - Reduction and Scan operations now works with more shared memory back-end - Altivec support is now complete for the VMX ISA We wish to thanks Ian Masliah for his work on MAGMA, Antoine Tran Tan for the shared memory support and Pierre Esterie participation to the Altivec ISA completion. Special thanks to Tim Blenchmann and khegeman for their help and patch submisisons throughout this development. The release Changelog is here : https://github.com/MetaScale/nt2/releases/tag/3.1.0 The files can be download from : http://nt2.metascale.org/downloads/ The Documentation (in progress) is here : http://nt2.metascale.org/doc/html/index.html **Next release announcment** This release is the last C++03 compliant version of both NT2 and Boost.SIMD. The next release - 4.0 - will be C++11 only. The new minimal version of supported compilers will be : - g++ 4.6 - Microsoft Visual Studio 12 (2013) - clang 3.4 - icc 12.1 The main reason for this change is to be able to properly fix the compile-time issue that one may experience. It'll also allow us to use some C++11 feature to simplify or streamline some of the user interface. * The NT2 Team

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Is there something like shared_array<T> but with iterators?
by david.hagood＠gmail.com 15 Oct '14

15 Oct '14

I am doing signal processing, and in order to avoid data copies I need something that: 1) can adopt a buffer of data (e.g. take ownership of a T*) 2) Release that buffer via an appropriate method (e.g. take a deallocator object). 3) Provide operator[] over that buffer 4) provide shared ownership semantics So far, that's shared_array<> to a T [sic] However, I need one more thing: 5) provide iterator support (begin(), end(), cbegin(), cend()) The current shared_array<> doesn't provide that - is there anything else that does?

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[interprocess] BOOST_INTERPROCESS_SHARED_DIR_PATH from env variable
by Jakub Szymanski 11 Oct '14

11 Oct '14

Hi, Will it be possible to have shared_dir not hardcoded? Currently it is determine by some tricks (some involve event log parsing on windows, which fails a lot). The only practical solution for us was to use BOOST_INTERPROCESS_SHARED_DIR_PATH define. boost/interprocess/detail/shared_dir_helpers.hpp inline void get_shared_dir(std::string &shared_dir) { #if defined(BOOST_INTERPROCESS_SHARED_DIR_PATH) shared_dir = BOOST_INTERPROCESS_SHARED_DIR_PATH; #else get_shared_dir_root(shared_dir); #if defined(BOOST_INTERPROCESS_HAS_KERNEL_BOOTTIME) shared_dir += "/"; get_bootstamp(shared_dir, true); #endif #endif } That has limitations tough as it makes it very difficult to test software in isolation (it requires access to the same folder). Similarly it makes is difficult to run program of machines with different file structure. Can it be configurable by some environment variable ? cheers --jakub

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[Modularization] master and develop on super project.
by Kohei Takahashi 10 Oct '14

10 Oct '14

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi all, Is there any policies for merging develop into master and sending pull-request on super project (boost.git)? Before 1.56.0 release, each libraries merged develop into master, though boost.git didn't. It caused to remain some defects in master (also release archive), which are already fixed in develop branch. e.g. - - https://svn.boost.org/trac/boost/ticket/5677 - -- https://svn.boost.org/trac/boost/ticket/6946 (dup of #5677) - - https://svn.boost.org/trac/boost/ticket/10507 and more tickets might exist... The wiki[1] describes about each libraries, but about super project is still absent. [1] https://svn.boost.org/trac/boost/wiki/StartModWorkflow Thanks, Kohei Takahashi -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJUN8IGAAoJEGGyPxPRp/zoW3QP/RBWJ7dcmS8TEr7SpQW97QW4 17chTXKLkqHboHxCJuswXb1rlnmBxxooFItA5kFudEu7U1x5OekPfw+oroQP7v+C CgS5eHanitjprkijvJO2SS61a/YdF/1hMJuHUWzd62hI5ZXWQvNryeJtNl0K0hFb H9EhniJltvBxjOOdvjUsd9XCPby1afi5jOCUjC3J08X6WruRuI5BhCNElVQOSxMG yzaxuLeFDy8L9CICAU8RNEkBEjY1n5rYAVnbETX1WSSoDGEHblRUTOT7JQwSuWWx 0ymdz5cHisM+QoGuLUI0BQS9mayik3vAsre68Ve/xxTHU3LaRRVvaLJIH0YrRRwX fQmyJVGtIbUIhgfmdK8mq050wNOwdzefVfGDkq/XNo+wwlwA6vS4D5gqzfthNL6S HdXI8TIJtdRUYk66vFVcL5uf3PjoW4cZpWYceq1h1EOsIfXuzpr6uO0NDhqEFD+D I3vSmGPV1eAPYpQHP7jeOePMn1EPItU0sVqLk0f6ymafyqnaPU52zhcS45VMS85Q krk+ixO5bND6IU0EgYDn7QZHrTdACDcH5UGscBmxrSUwJ4DrgB6q8mAG/Ek0lZBK /UyXOu3k+ZtrYQIu5aayIyANp6p/EKGNgT7F7/4t0WZzxleskEPzKX9XKoPJnjQ9 aZrV3aXQSRrlEeBhU4fk =KrkS -----END PGP SIGNATURE-----

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[config] Need some clang testing help...
by John Maddock 09 Oct '14

09 Oct '14

Folks there are persistent bug reports relating to clang with libstdc++ not correctly detecting the std lib feature set, see https://svn.boost.org/trac/boost/ticket/7473 for a lengthy discussion on the issue, and why it's been unsolvable. Anyhow, I've just committed a tentative patch in https://github.com/boostorg/config/commit/b36566fe04a89103b7ef5569c03e3a26e… and I'd be grateful if as many folks as possible can test this with their clang/linux/libstdc++/C++11 setups as they can. It works well for me locally, but that's only one possible clang configuration. BTW the easiest way to patch your Boost version is probably to download a replacement libstdcpp2.hpp from here: https://raw.githubusercontent.com/boostorg/config/b36566fe04a89103b7ef5569c… Many thanks in advance, John.

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[range] How does remove_erase() work?
by Stephan T. Lavavej 08 Oct '14

08 Oct '14

Hi, I'm updating my Uniform Container Erasure proposal [1], and I was informed that Boost.Range has a similar-ish remove_erase(). I have a very simple question about its implementation, so I can describe it accurately in my revised proposal, but I don't really want to look at erase.hpp's guts. Does remove_erase() just use the erase-remove idiom, or does it contain special cases for the vector-like family, list-like family, and map-like family? (As N4009 explained, the erase-remove idiom is suboptimal for list, and won't compile for forward_list and the map-like family.) Thanks, STL [1] http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4009.htm

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It's that time again already - Boost 1.57.0 schedule
by Marshall Clow 08 Oct '14

08 Oct '14

It’s that time again. Here’s the schedule for the upcoming 1.57 release. If you’ve got changes that you’ve been putting off making, now’s the time to get busy. * 13-Oct Last day for significant changes * 20-Oct Beta build * 27-Oct Automatic merging turned off, build an RC * 3-Nov Release Boost 1.57.0 Questions? Ask them here. — The Boost release managers. P.S. We’ll be updating the calendar on boost.org/development soon.

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Update on status of C++ 11 only Boost fork/modular distro
by Niall Douglas 08 Oct '14

08 Oct '14

Dear all, You may remember me saying these past six months that I was working on the tools necessary to fork Boost into a C++ 11 only distro which also lets you use Boost libraries individually standalone without the rest of Boost. I have got a first alpha version of my clang AST based local bindings generator working, and you can see it at https://github.com/ned14/local-bind-cpp-library. This tool lets you generate a set of local namespace bindings for some implementation of some library such that your library implementation code need not care what the underlying implementation of dependent library facilities is. This way your Boost library could be using either Boost or the C++ 11 STL and you don't need to care (most of the time). Now I have the first alpha version working and generating a reasonable set of C++ 11 STL bindings (https://github.com/ned14/local-bind-cpp-library/tree/master/include/s tl11), I'll start with porting over my own Boost libraries to it, so Spinlock, Expected, non-allocating future-promise and AFIO will be the first, and with those AFIO should become capable of being completely standalone from Boost whilst still also able to compile against Boost. After that I'll try porting the entire of Boost.Thread over such that Boost.Thread no longer needs Boost. I think that would be hugely useful for people wanting to use potential C++ 17 threading functionality without needing to draw in all of Boost as a dependency, and that might greatly widen the empirical experience new threading facilities might get before the 17 standard. Once I've succeeded with that, if the present situation with Boost has not improved by then, I'll press ahead with a new Boost distro website which score ranks Boost modules according to the scoring manifest I outlined on this list some months ago, and lets you download standalone Boost distros of your choice. Obviously only libraries ported to be standalone capable would be available, so I would hope that if I can demonstrate an easy port with Boost.Thread, others may follow with their libraries. All this work occurs in my free time of a few hours per week, so progress will be slow but steady. Comments on the local namespace binding tool are welcome. Comments on the proposed C++11/14 good practice idiom of binding dependent library APIs into the local namespace are also welcome, because as far as I can tell no one here has discussed a formal set of conventions to make best use of inline namespaces for new libraries. I'll put it another way - local namespace binds are a poor man's version of Herb's proposed C++ ABI facility. As much as they aren't quite as good, they are probably good enough (relative to Herb's most recent proposal). Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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Fusion and constexpr, C++11 support entirely broken on develop
by Mathias Gaunard 07 Oct '14

07 Oct '14

Hi folks, I recently decided to move all of my code to C++11, and I usually use the develop version of each library so that I can have the latest developments and can easily contribute. However, Fusion appears to be fundamentally broken on develop whenever C++11 is enabled with GCC. It works fine with C++03. I don't think this is a situation that should ever happen; while develop is for libraries undergoing development, it shouldn't be totally broken either. In particular, the problem is that it uses BOOST_CONSTEXPR in contexts where C++11-constexpr is invalid, but where it is valid in C++14. Should there be a separate BOOST_CONSTEXPR14 macro?

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[EXTERNAL] Tickets notifications
by Adam Wulkiewicz 07 Oct '14

07 Oct '14

Hi, AFAIU the notifications about new tickets and updates are sent only to the owner of the library. This is inconvenient since many libraries are developed by a group of people, e.g. Geometry. I'm aware that anyone can get updates if he's on the Cc list but people which are curious about development aren't added to this list automatically. Ideally it would be great if any user could subscribe to get notifications for any library like it's possible on GitHub. Or maybe moving to GitHub mentioned by John in one of the other threads would be the best solution? Anyway, is it somehow possible to receive notifications as a non-owner automatically? If the answer was no, would sending notifications to the library mailing list be a reasonable solution? AFAIU this could be done by adding a "fake" owner with a mailing list email. Regards, Adam

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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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