June 2009 - Boost - lists.preview.boost.org

Proposal: Monotonic Containers
by Christian Schladetsch 21 Jun '09

21 Jun '09

Hello, There is a need in high-performance realtime software to use containers that may only grow in size. These are typically reset at the end of each update cycle. The proposal here consists of a base 'monotonic allocator', which takes its storage from a buffer that you provide. Allocations are made from this buffer, and deallocation only calls an object's destructor; no actual memory-management is performed at all. This is very useful for realtime systems that have to do things like, for example, physics or renderering systems. These systems build up lists and other containers over the period of an update frame, however at the end of that frame the storage can just be reset. The benefit of using this system over a normal std::allocator is that memory is not fragmented, and memory allocation and deallocation is basically optimal. Within the package are: boost.monotonic.inline_storage boost.monotonic.list boost.monotonic.vector boost.monotonic.map boost.monotonic.set boost.monotonic.ptr_list I didn't bother adding the other ptr_* containers yet. The files for the proposal are in the vault at http://www.boostpro.com/vault/index.php?action=downloadfile&filename=Monoto… . I'd be happy to address any issues or comments. There are some improvements that could be made. Regards, Christian.

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DateTime conversion to tm problem?
by Maciej Sobczak 21 Jun '09

21 Jun '09

Hi, The posix_time::to_tm function clears the date fields of the std::tm structure. Having zeros on year, month and day fields represent the 1900-01-00 date according to the std::tm conventions, which is a date that did not exist. Using such value with other APIs might result in out of range conditions. Is it considered to be a problem? What about setting tm_mday to 1 instead (which would represent 1900-01-01 - that is, the first legal date)? Regards, -- Maciej Sobczak * www.msobczak.com * www.inspirel.com

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[BOOST_ASSERT] any one against improving debug support?
by Thorsten Ottosen 21 Jun '09

21 Jun '09

Hi, The current difinition of BOOST_ASSERT is a pain to use with the debugger and Boost.Test because it doesn't trigger a break-point. Does anyone object to defining it like this in <boost/assert.hpp> #if (BOOST_MSVC >= 1400) #include <crtdbg.h> #define BOOST_ASSERT _ASSERTE #endif ? -Thorsten

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policy on compiler warnings?
by Kenny Riddile 21 Jun '09

21 Jun '09

Does Boost have any documented policy on compiler warnings? I, like a lot of people, use warning level 4 when compiling with MSVC. I also usually turn on warnings as errors, but I cannot easily do that since many Boost libraries emit warnings at warning level 4 under MSVC9. I realize that warnings aren't really standardized across compilers, but I would still expect a project that touts itself as "...one of the most highly regarded and expertly designed C++ library projects in the world." to strive for zero warnings under a commonly used setting on one of its official test compilers. I have created the following tickets regarding warnings that are currently causing me trouble: https://svn.boost.org/trac/boost/ticket/3193 https://svn.boost.org/trac/boost/ticket/3194 https://svn.boost.org/trac/boost/ticket/3195 https://svn.boost.org/trac/boost/ticket/3196 https://svn.boost.org/trac/boost/ticket/3197 Thanks, Kenny Riddile

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[config] missing include for FreeBSD
by k-oli＠gmx.de 20 Jun '09

20 Jun '09

Hi, boost/config/platform/bsd.hpp misses include sys/param.h. Without this header __FreeBSD_version can not be evaluated. regards, Oliver

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convert boost::mpl::vector_c<int> into const int[]
by Peter Foelsche 20 Jun '09

20 Jun '09

Is there any way to convert a boost::mpl::vector_c<int> into a const int[] without using boost::mpl::for_each?

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[task] Minor issues
by Chard 19 Jun '09

19 Jun '09

I've been trying out the task library from the vault and have found a few issues. The code does not compile with MSVC 7.1; this appears to be a compiler non-conforming issue rather than code error: The contained impl_pool class inside detail::worker requires access to the static pool class, but even though the detail::worker class is a friend, VC7 doesn't allow impl_pool access. Adding: template< typename Pool > friend class detail::worker::impl_pool; to the class in static_pool.hpp gets around this. <> I believe there is another error in the task config.hpp file; it has the line: # if defined(BOOST_TASK_DYN_DLL) || defined(BOOST_ALL_DYN_LINK) I believe BOOST_TASK_DYN_DLL should be BOOST_TASK_DYN_LINK, following the guide from the main boost config.

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[polygon] GTL name change and pre-review issues
by Simonson, Lucanus J 19 Jun '09

19 Jun '09

I am changing the name of my library from GTL (Geometry Template Library) to boost::polygon and narrowing the scope from "computational geometry" to "polygon manipulation". This scope precisely describes the current scope of what is implemented. It also clarifies the position of the library relative to similar proposals. I have already moved the code into boost::polygon namespace, added dependency on boost::enable_if and gotten the unit tests compiling and passing in windows with the new namespace and dependency. I wanted to ask about the gtl_yes and gtl_no types I use for metaprogramming, defined thus: struct gtl_no { static const bool value = false; }; struct gtl_yes { typedef gtl_yes type; static const bool value = true; }; I need to define type as gtl_yes in gtl_yes and leave it undefined in gtl_no to enable early SFINAE to work around an EDG compiler bug: template <typename geometry_type_1, typename coordinate_type_1> typename enable_if< typename gtl_and< typename is_mutable_polygon_90_set_type<geometry_type_1> #ifdef __ICC ::type #endif ::type, typename gtl_same_type<typename geometry_concept<coordinate_type_1>::type, coordinate_concept>::type> #ifdef __ICC ::type #endif ::type, geometry_type_1>::type operator-(const geometry_type_1& lvalue, coordinate_type_1 rvalue) { geometry_type_1 retval(lvalue); retval -= rvalue; return retval; } Here I am short circuiting template instantiation in the case that ICC (using EDG) is detected by calling the gtl_yes/gtl_no metafunction. This would be a syntax error in MSVC, of course. I need to do this for arithemetic operators because EDG incorrectly tries to match them to operators between pointer and unnamed enum type values in the stl and throws a syntax error when I refer to the unnamed enum type in the declaration of the operator. By SFINAEing out early I can work around this bug, which is fixed in the latest EDG versions, but I need to support older versions as well. Is it acceptable to continue to use my own definitions for true_type/false_type, or does someone have a suggestion for a different workaround that will allow me to replace gtl_yes/gtl_no with boost::true_type, boost::false_type? By the way, complete documentation for my library is now available at https://svn.boost.org/svn/boost/sandbox/gtl/doc/index.htm Feedback on the documentation before the formal review will help me get ready for the review. I'll be checking review ready code into the sandbox later today along with unit tests. If someone can point me to setup my unit test source file to work with the boost unit testing system I'd greatly appreciate it. Right now it just uses returning an error code to indicate test failure, and it is all or nothing in that sense. Regards, Luke

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Proposed addition to the iterator library for iterating over all tuples.
by Alex Mendes da Costa 19 Jun '09

19 Jun '09

Hi folks: I quite often have to write code to do the following: Given N sequences, generate all the N-tuples s.t. the i'th element in each tuple is drawn from the i'th sequence. For example, if sequence S1 is { 1, 2, 3 } and sequence S2 is { 10, 20 }, I need to generate these tuples: (1, 10), (2, 10), (1, 20), (2, 20). I think this problem could be solved elegantly with a iterator similar to zip_iterator. I have some questions: (1) Is there already a way to do this in boost? (2) If not, would this be a worthwhile addition to the iterator library? (3) If so, could I contribute code for this, or must the existing library owners write it? (4) If so, how would I go about getting my code added? Most of the docs seem to be about submitting entire libraries, rather than extensions to existing libraries. Thanks, Alex

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Boost.Bloom_filter now in Sandbox (WAS Re: Interest in a Bloom Filter?)
by Dean Michael Berris 19 Jun '09

19 Jun '09

On Mon, Jun 8, 2009 at 2:55 PM, Dean Michael Berris<mikhailberis(a)gmail.com> wrote: > On Mon, Jun 8, 2009 at 2:47 PM, Joaquin M Lopez Munoz<joaquin(a)tid.es> wrote: [snip] > > Thanks for your insights! I'll make the changes and then maybe put it > in the sandbox along with the documentation that I'll be working on. > The implementation is now available in Boost's Sandbox. You can check out the implementation along with the documentation via: svn co https://svn.boost.org/svn/boost/sandbox/bloom_filter/trunk/ Can someone please add this to the Libraries Under Construction page? I'd also like to request to add this to the formal review queue (if this qualifies for a fast track review, that would also be an option I'm open to). Thanks in advance, and I hope this helps. -- Dean Michael Berris | Software Engineer, Friendster, Inc. blog.cplusplus-soup.com | twitter.com/mikhailberis | linkedin.com/in/mikhailberis | profiles.friendster.com/mikhailberis | deanberris.com

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