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[gsoc] Proposal for Generic Trie, Radix Tree, and Suffix Array Data Structures
by Chris Wagner 17 May '09

17 May '09

Hello, I am interested in writing a library consisting of generic implementations of several common data structures and algorithms primarily useful in text-processing. I believe these would be useful additions to Boost and would like to work on them for GSoC. Before I submit my proposal, I would like to hear whether or not the community agrees that this is a good idea, and I would appreciate any suggestions or comments offered. My plan is to implement a trie / prefix tree data structure, STL set/map-like classes implemented over the trie, a radix tree, a suffix tree implemented over the radix tree, and a suffix array. These would be instantiable over arbitrary sequence types, and use iterator traits to determine the contained type. I am a student at Kent State University, working on an M.S. in Computer Science in a combined undergraduate/graduate program. I have a particular interest in computational linguistics, and I will admit that am especially interested in this project because of how it could be applied to my own field, but I believe that these types would be of general utility to the programming community as a whole. Thank you for your time, Chris Wagner

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[futures] is there an updated version of futures
by Yigong Liu 16 May '09

16 May '09

Hello, Is there an updated version of futures lib by Anthony after the review? Is the one dated 20090530 still the latest one publicly avaialble? Thanks Yigong

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[exception] Virtual inheritance with no default constructors
by Adam Badura 16 May '09

16 May '09

The Boost.Exception library mandates that exceptions classes hierarchy should use virtual inheritance (http://www.boost.org/doc/libs/1_39_0/libs/exception/doc/using_virtual_inher…) The document notes that this does not go well with exceptions without default constructors ("(...) Note that virtual bases are initialized directly by the constructor of the most-derived-type (...)") however this should not be a concern as boost::exception provides other means to transport data. What is missing is however documentation that in normal circumstances boost::throw_exception cannot be used with exceptions types which have in their inheritance graph virtual base classes which are not default constructible. This is because boost::enable_current_exception constructs the clone_impl object which inherits the actual exception type and copy-constructs it. However this code will not compile if some base class of the callers exception type is virtual and non-default constructible. In my opinion few changes seem appropriate: 1) Note in the documentation explicitly this requirement (possibility of default construction). 2) Name an entity which should be made friend of exception class to use its non-public default constructor. This entity would be latter used by clone_impl. This way an exception could be default constructible only for this particular use case. 3) Provide means to late-initialize exception object. This would bypass the default construction problem (and goes well with private default constructor as described in 2)). 4) Allow to specify in boost::throw_exception (or similar places) not only the exception type but as well its (virtual) base types so that latter clone_impl could mention them on the initializers list as well and copy-construct them. (As far as I know there is no way of automatic detection of base types thus caller must specify them explicitly - however if I am mistaken such automation would be even better.) Adam Badura

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Re: [boost] [rfc] Unicode GSoC project
by Graham 16 May '09

16 May '09

>What kind of real-world use do people have for random access, anyways? >Even UTF-32 isn't random access for the things I can think of that >people would care about, what with combining codepoints and ligatures >and other such things. I wrote a couple of Unicode text editors that would have been a nightmare if they had not been operating on UTF-32. >As an aside, I'd like to see comparisons between compressed UTF-8 and >compressed UTF-16, since neither one is random-access anyways, and it >seems to me that caring about size of text before compression is about >as important as the performance of a program with the optimizer turned >off. Actually in a few cases I have seen it is not the compressed size but the conversion performance [memory/CPU] that hurts. It is much better to get the correct encoding for the correct use case. Yours, Graham

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Re: [boost] [rfc] Unicode GSoC project
by Graham 15 May '09

15 May '09

>I don't plan on supporting random access for UTF-16. >UTF-16 is still faster than UTF-8 because UTF-8 requires more complex >decoding. >UTF-16 has only two cases, making it easier to optimize branches under >the likely and unlikely case. Dear Mathias, Don't forget surrogates ! Yours, Graham

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Re: [boost] [rfc] Unicode GSoC project
by Graham 15 May '09

15 May '09

>I'll be reviewing it in a while. >I'm not too sure about the memory layout it uses (__uni_char_data could >really be compressed to use less memory for example), nor about the >interface it exposes, but it does seem to work well. >About is_grapheme_break though, isn't the implementation for legacy >grapheme cluster rather than extended ones though? Dear Mathias, The uni car data was laid out in that way for speed and simplicity. Please feel free to do it better. The grapheme break worked off the character attributes and standard rules. If it needs changing or did not cover a later standard, then it should be updated. The principle would not change as it makes the string iterators quite straightforwards.

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[rfc] Unicode GSoC project
by Mathias Gaunard 15 May '09

15 May '09

Hi everyone. I'm in charge of the Unicode Google Summer of Code project. I have been working on range adaptors to iterate over code points in an UTF-x string as well as converting back those code points to UTF-y for the past week and I stopped working on these for a bit to put together some short documentation (which is my first quickbook document, so it may not be very pretty). This is not a documentation of the final work, but rather that of what I'm working on at the moment. I would like to know everyone's opinion of the concepts I am defining, which assume the range that is being worked on is indeed a valid unicode range in a particular encoding, as well as the system used to enforce those concepts. Also, I put the normalization form C as part of the invariant, but maybe that should be something orthogonal. I personally don't think it's really useful for general-purpose text though. While the system doesn't provide conversion from other character sets, this can easily be added by using assume_utf32. For example, using an ISO-8859-1 string as input to assume_utf32 just works, since ISO-8859-1 is included verbatim into Unicode. The documentation contains as well some introductory Unicode material. You can find the documentation online here: http://mathias.gaunard.emi.u-bordeaux1.fr/unicode/doc/html/

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[C++0x] More config macros needed
by Beman Dawes 15 May '09

15 May '09

GCC 4.3 and even more so 4.4 have implemented significant portions of the C++0x core language, and provide lots of C++0x standard library components too. Microsoft 2010 beta 1 will ship "real soon", and it too will have some major C++0x core language features, and also some C++0x standard library components. Thus we need more config macros, particularly those aimed at the standard library. A possible approach: BOOST_NO_CONCEPTS // needed to tell if headers have been conceptized BOOST_NO_*_HDR // for each new C++0x header; * is name of header For example, BOOST_NO_CHRONO_HDR is defined unless header <chrono> is present. I'm proposing we not try to identify whether or no the header is complete. If BOOST_NO_CONCEPTS is defined, the header obviously hasn't been conceptized. Ditto anything else that depends on any other new core language feature that hasn't been implemented. Other incomplete aspects will have to be dealt with by testing the library version. We don't want feature macros to proliferate unduly; they are more work to create and maintain than you might think, and if there are a lot of them it gets very confusing. Comments? --Beman

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[Preprocessor] Can we generate token for #include programmatically ?
by Joel Falcou 15 May '09

15 May '09

Here is what I had in mind #define BASE foo.hpp #include BOOST_PP_STRINGIZE(BOOST_PP_CAT(nt2/support/numeric/functions/scalar/,BASE)) It fails because it seems we can't paste stuff ending with / ... Using fiel iteration, how can I circumvent hsi problem and generate a list of #include whose filename are computed from a sequence of name in a BOOST_PP_SEQ and a given, changing, prefix path ?

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Re: [boost] [rfc] Unicode GSoC project
by Graham 15 May '09

15 May '09

Dear Eric/ Mathias, >That's good, these are needed. Also needed are tables that store the various >character properties, and (hopefully) some parsers that build the tables >directly from the Unicode character database so we can easily rev it >whenever the database changes. A good reloadable character library is in the vault. >And UnicodeGrapheme concept doesn't make sense to me. You say, "A model of >UnicodeGrapheme is a range of Unicode code points that is a single grapheme >cluster in Normalized Form C." A grapheme cluster != Unicode code point. It >may be many code points representing a base character an many zero-width >combining characters. So what exactly is being traversed by a >UnicodeGrapheme range? >It is thus important to be able to apply algorithms with graphemes as the >unit rather than code points to deal with graphemes not representable by a >single code point. I think that a grapheme is more of an iterator concept than a data type concept. By specialising it you will unnecessarily complicate any library. Don't forget that, for example, the current grapheme may start as one character, then suddenly 'grab' the surrounding characters as it makes a combined glyph. I have never found a use case in practise where specialising the grapheme as other than a validated series of code points was helpful. The two cases where graphemes are important is in display [which requires intermediate glyph conversion anyway, and works just as well on runs of code points, so code points are fine] and in editing - and the grapheme-ness here alters during typing. >The Unicode standard also specifies various features such as a collation >algorithm in Technical Standard #10 - Unicode Collation Algorithm for >comparison and ordering of strings with a locale-specific criterion, as >well as mechanisms to iterate over words, sentences and lines Have a look at the character library that I posted in the vault - if you can do graphemes then you can do words, paragraphs etc as they are all just attributes of the characters with simple rules. Graphemes come in to their own for text display and editing and you would need these as well to be able to support that. Don't forget that windows GDI only supports point arithmetic and this means that you need to be able to locate word boundaries to display text well at different scales to work around the GDI scaling rounding [and GDI+ is not much better].

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[1.39.0] Beta candidate
by Beman Dawes 15 May '09

15 May '09

The beta candidate files are up at http://boost.cowic.de/rc/ Before pushing these out to SourceForge, it would be great if a few Boosters could download and try them out as a final QA check. Post your experiences here. Thanks, --Beman

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Review Request: Algorithm.Sorting
by Steven Ross 15 May '09

15 May '09

I have uploaded algorithm_sorting.zip for a formal review to become Boost.Algorithm.Sorting, if people feel that is appropriate. It is 3 templated hybrid radix-based/comparison-based algorithms, specialized to sort certain types of data more efficiently. All 3 have superior worst-case and average-case performance to std::sort, based upon my testing. None of these algorithms use much additional memory. All of them can sort key + data, and as they do fewer swaps, tend to do so much faster than std::sort. As a general rule, the speedup of these algorithms relative to std::sort increases as data set size increases. These algorithms tend to be faster relative to std::sort when comparisons are slow, as they do less (or no) comparisons. string_sort, which sorts strings in O(n*length) time, as compared to O(n*length*log(n)) for pure comparison-based algorithms. It is consistently faster than std::sort in string sorting, by a little more than a factor of 2 based upon my testing. float_sort, which sorts IEEE floating-point numbers as integers, but attaining the same ordering as std::sort, with the exception of -0.0 and NaNs, both of which cannot be ordered based upon their comparison function. float_sort is roughly twice as fast as std::sort on UNIX-type OSes I've tested on, and roughly 7X as fast on Windows. I believe this speedup to be because floating-point comparisons are slow on Windows. integer_sort, which sorts integers around 60% faster than std::sort on UNIX-type OSes, and 25% faster on Windows. On Windows with MSVC, std::sort sorts already-sorted and small range data extremely quickly, and integer_sort processes already-sorted data slower than it by as much as a factor of 3X. I believe this to be due to some optimization for already-sorted data, as integer_sort takes substantially less absolute time on already-sorted data than unsorted data. So integer_sort on Windows has a tradeoff: better worst-case and average-case performance, but worse best-case performance. integer_sort and float_sort share some tuning parameters. I have set values that seem to work well on both UNIX-type and Windows OSes, but people are welcome to try to see what values are best for their system and problem type. The ideal values for integers and floats may be different on some systems (such as Windows), but for simplicity they are kept the same. A tuning/testing script named tune.pl is included, for those who wish to see how fast these algorithms are on their system (and verify correctness). I don't recommend using it for tuning without the -large option, and that takes days. If you do use it for tuning, I also recommend the -verbose option, to see what it's doing.

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[exception] current_exception mishandling standard exceptions
by Adam Badura 14 May '09

14 May '09

It seems that current_exception mishandles standard exceptions. I noted two problems: 1) Some standard exceptions are not handled at all. This includes std::runtime_error and its derived (std::overflow_error, std::range_error, std::underflow_error), std::domain_error (handled by general std::logic_error), std::length_error (handled by general std::logic_error) and std::ios_base::failure (handled by general std::exception). Why is it so? 2) Non-standard exceptions derived from standard exceptions are sliced by current_exception. It detects those types by throwing and caching and thus will catch also derived types (like null_pointer : public std::invalid_argument). But during construction of internal structures the standard exception type is used and thus copy construction slices the original exception object. If typeid was used instead of throwing/catching (or dynamic_cast) to detect the type current_exception could at least detect that is will slice the original object and use a different type so it would not pretend everything is OK. Adam Badura

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[property_tree] XML parser broken in 1.39.0
by Boris Schaeling 14 May '09

14 May '09

Calling boost::property_tree::xml_parser::read_xml() to parse a XML file and populate a property_tree doesn't work anymore in Boost 1.39.0 (at least not in Visual C++ 2008). The compiler error I see is: boost\iterator\iterator_adaptor.hpp(230) : error C2027: use of undefined type 'boost::STATIC_ASSERTION_FAILURE<x>' with [ x=false ] The property_tree headers include boost\spirit\home\classic\iterator\position_iterator.hpp which includes boost\iterator\iterator_adaptor.hpp. I also see this warning: Warning: This header is deprecated. Please use: boost/spirit/include/classic.hpp Warning: This header is deprecated. Please use: boost/spirit/include/classic_position_iterator.hpp It looks like as if a change in Boost.Spirit or Boost.Iterator broke the XML parser. Does Boost.PropertyTree have a maintainer who can look into this? Boris PS: As it turns out it's broken in Boost 1.38.0, too. With 1.36.0 I don't get a compile error (1.37.0 I don't have installed and can't test).

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Re: [boost] [rfc] Unicode GSoC project
by Graham 14 May '09

14 May '09

> 1. The vast majority of characters (by frequency of use) are > on the BMP. > 2. For seamless integration with the majority of existing > software with good Unicode support. > >I don't find either of those claims very convincing. I hope that your >library will not try to make UTF-16 some sort of default encoding, or >otherwise give it special treatment. Phil, I think each application needs to be assessed on its own merits. For example: For data storage on mainly ASCII text I use UTF-8. For text manipulation I often use UTF-16. For a Unicode text editor I use UTF-32. There is not a one size fits all. Yours, Graham

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New version of C++ Middleware Writer now on line
by Brian Wood 14 May '09

14 May '09

Shalom Version 1.9 of the C++ Middleware Writer is now available. This version adds support for Boost Array and it also has a command line interface that allows users to bypass the web interface. In other words, it makes it easy to integrate the C++ Middleware Writer into your build process. http://webEbenezer.net/build_integration.html<http://webebenezer.net/build_integration.html> -- Brian Wood Ebenezer Enterprises http://www.webEbenezer.net <http://www.webebenezer.net/>

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Binary compatibility of boost releases. Is there such a thing at all?
by Alexander Churanov 14 May '09

14 May '09

Hi folks! I am working on boost port for FreeBSD. At present I am investigating into versioning of shared libraries. Historically, versions of boost shared libraries on FreeBSD do not match boost release version. Some FreeBSD folks beleive that application should not be recompiled just because the boost was updated, say from 1.37 to 1.39 and that shared library version for 1.39 may stay the same as it was for 1.37. I'm afraid it's not correct. I've read that there is no binary compatibility for boost shared libraries from different releases, and that application must use exactly the same library it was compiled for. However, these documents are of 2003-2004. Here is the question: What is the actual status of binary compatibility for boost? Alexander Churanov, maintainer of devel/boost

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[future] usage question for new accepted library
by Alan Patterson 14 May '09

14 May '09

Hi, I see Anthony William's future implementation has been accepted over Braddock Gaskill's. I have been using Braddocks implementation and in particular a couple of features which I believe are not in Anthony's implementation. So I am looking for some pointers for how I might do the following with the accepted futures implementation. 1) Using the implicit cast of future<T> to T. I have an application where I can submit jobs to a scheduler, have them executed and provide me with a return value. My scheduler uses a policy for implementation: scheduler<single_threaded_policy> scheduler<threadpool_policy> The user submits a task and gets the result like result_type r = scheduler.submit(some_task()); where result_type is obtained from the scheduler and can either be of type T for single_threaded or future<T> for threadpools. Either way the client doesn't care which, because he can use a T or future<T> identically IF future<T> casts to T. I like this because the client never knows anything about futures, he treats all result_types as type T. I guess the way to do this with the accepted future implementation is to create a template function that does the following: T actual_r = get<result_type>(r); which call get() if it is a future or just returns r if not. But this is no where near as nice IMHO. The user no longer just uses the result_type of his task directly for what seems to be a basic type. 2) callbacks when future is set I have a usage scenario where I submit a batch of tasks where I collect results until I either have the result I want or collect enough that I can return what I have. This is neither a wait_for_any or a wait_for_all, more a kind of wait_until_i_have_enough. I currently implement this by submitting the batch of tasks and getting a batch of futures. I then register a callback on each future that gets called as each future gets set. The callback collects results as they come in and can decide to bail out early if it has enough results. How would I go about implementing this usage with the new futures implementation? Thanks in advance and sorry for the long post. Alan

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Comment spam in bugs
by Sebastian Redl 14 May '09

14 May '09

There's comment spam in this bug: https://svn.boost.org/trac/boost/ticket/1989 Is there a unified way for reporting this, aside from posting here? Sebastian

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[RFC] thread::access_monitor
by Gregory Petrosyan 14 May '09

14 May '09

I would like to hear your comments on the idea behind access_monitor template, which ensures (at compile-time) that data, protected by it, can be accessed only with associated lock held. It can be useful when you want to expose all the native interface of your data type (STL container, for example): in such a case, using ordinary monitor pattern is almost impossible. Example usage: typedef access_monitor<data_type, mutex_type> data_access_monitor; void f(data_access_monitor const& d) { data_access_monitor::value_type const* data; data_access_monitor::lock_type lock; boost::tie(data, lock) = d.const_lock(); // do something with data here } Code: #include <boost/thread.hpp> #include <boost/tuple/tuple.hpp> template <typename T, typename Lockable> struct access_monitor { typedef T value_type; typedef boost::unique_lock<Lockable> lock_type; private: typedef boost::detail::thread_move_t<lock_type> lock_move_type; public: boost::tuple<value_type const*, lock_move_type> const_lock() const { lock_type lock(mutex_); return boost::make_tuple(&data_, lock.move()); } boost::tuple<value_type*, lock_move_type> lock() { lock_type lock(mutex_); return boost::make_tuple(&data_, lock.move()); } private: // mutex_ is guaranteed to be locked when you access data_ mutable Lockable mutex_; T data_; }; Sorry for draft-quality code (however, something like the above compiles with MSVC 9). Please CC me, because I am not subscribed. Gregory

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[random] cross-platform secure seeding methods planned?
by Sebastian Nowozin 14 May '09

14 May '09

Hello everybody, I like the flexibility boost::random offers. However, a severe drawback of the current library is that it does not offer a safe way of generating seeds. Of course the methods for providing this feature would vary quite a lot across platforms (e.g. on some systems its safe to use /dev/random, on some it is not). However, as the library is currently, many users will resort to ad-hoc or unsafe seeding methods instead of implementing a safe solution themselves. Hence, is a cross-platform secure seeding feature planned for boost::random in the future? Thanks, Sebastian

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[exception] Lifetime of exception refered to by exception_ptr
by Adam Badura 14 May '09

14 May '09

I failed to find in Boost.Exception documentation any note on how long is the lifetime of an exception object referred to by an exception_ptr. Also I failed to find it in the referred N2179 (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2179.html) It seems logical to assume that the lifetime is not shorter then the lifetime of any exception_ptr object referring to the exception object. N2179 suggests possibility of use of smart pointer as implementation of exception_ptr which makes that assumption even more justified. However I think that documentation should be explicit with this. Adam Badura

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[iterators] Proof-of-concept for a sentinel iterator adapter
by Beman Dawes 13 May '09

13 May '09

Attached is proof-of-concept code for a sentinel iterator adapter. It turns a pointer to sentinel terminated sequence, such as a C-style string, into a forward iterator with a conforming end iterator. This is more efficient than doing a separate sequence traversal just to find the end. I'm a little surprised that Boost doesn't already have such an iterator adapter. Or am I just missing it? Would a production version of this iterator adapter be a worthwhile addition to Boost.Iterators? Any other comments appreciated, --Beman // sentinel terminated sequence iterator proof-of-concept // Copyright Beman Dawes, 2009 #include <cassert> // sentinel terminated sequence iterator template < class T, T Sentinel = T() > class sentinel_iterator { public: sentinel_iterator() : m_ptr(0) {} // construct end iterator sentinel_iterator( T * p ) : m_ptr( (p && *p != m_sentinel) ? p : 0 ) {} sentinel_iterator & operator++() { assert(m_ptr); if ( *++m_ptr == m_sentinel ) m_ptr = 0; return *this; } T & operator*() const { assert(m_ptr); return *m_ptr; } bool operator==( const sentinel_iterator & rhs ) const { return m_ptr == rhs.m_ptr; } bool operator!=( const sentinel_iterator & rhs ) const { return m_ptr != rhs.m_ptr; } private: T * m_ptr; // 0 == the end iterator static const T m_sentinel = Sentinel; }; int main() { // test cases using default sentinel sentinel_iterator<char> it( "abc" ); assert( it != sentinel_iterator<char>() ); assert( *it == 'a' ); assert( *++it == 'b' ); assert( *++it == 'c' ); assert( ++it == sentinel_iterator<char>() ); sentinel_iterator<char> it2( "" ); assert( it2 == sentinel_iterator<char>() ); sentinel_iterator<char> it3( 0 ); assert( it3 == sentinel_iterator<char>() ); // test cases using non-default sentinel typedef sentinel_iterator<unsigned, -1> my_iter_type; unsigned data[] = { 0, 1, -1 }; my_iter_type my_it( data ); assert( my_it != my_iter_type() ); assert( *my_it == 0 ); assert( *++my_it == 1 ); assert( ++my_it == my_iter_type() ); unsigned my_sentinel = -1; my_iter_type my_it2( &my_sentinel ); assert( my_it2 == my_iter_type() ); my_iter_type my_it3( 0 ); assert( my_it3 == my_iter_type() ); return 0; }

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Boost::Lambda + Boost::Tuple + unresolved overloaded function type
by Dmitry V. Krivenok 13 May '09

13 May '09

Hello! I wrote two simple examples to demonstrate the problem. First one is: //////////////////////////////////////////////////////////////// #include <vector> #include <utility> #include <algorithm> #include <cassert> #include <boost/lambda/lambda.hpp> #include <boost/lambda/bind.hpp> int main() { std::vector<int> v1; v1.push_back(1); v1.push_back(2); v1.push_back(3); std::vector<std::pair<int*, bool> > v2; namespace bll = boost::lambda; std::transform(v1.begin(), v1.end(), std::back_inserter(v2), bll::bind(std::make_pair<int*, bool>, &bll::_1, true)); assert(v2.size() == 3); return 0; } //////////////////////////////////////////////////////////////// This program compiles and works fine. The second program is: //////////////////////////////////////////////////////////////// #include <vector> #include <utility> #include <algorithm> #include <cassert> #include <boost/tuple/tuple.hpp> #include <boost/lambda/lambda.hpp> #include <boost/lambda/bind.hpp> int main() { std::vector<int> v1; v1.push_back(1); v1.push_back(2); v1.push_back(3); namespace bll = boost::lambda; std::vector<boost::tuple<int*, bool> > v3; std::transform(v1.begin(), v1.end(), std::back_inserter(v3), bll::bind(boost::make_tuple<int*, bool>, &bll::_1, true)); assert(v3.size() == 3); return 0; } //////////////////////////////////////////////////////////////// It doesn't compile: $ g++-4.3.2 -I /usr/local/dev/boost-1.38.0/include/ main2.cpp main2.cpp: In function 'int main()': main2.cpp:22: error: no matching function for call to 'bind(<unresolved overloaded function type>, const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::addressof_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, bool)' $ What's wrong in the second program? Thank you beforehand! -- Sincerely yours, Dmitry V. Krivenok Orange System Co., Ltd. Saint-Petersburg, Russia work phone: +7 812 332-32-40 cellular phone: +7 921 576-70-91 e-mail: krivenok(a)orangesystem.ru web: http://www.orangesystem.ru skype: krivenok_dmitry jabber: krivenok_dmitry(a)jabber.ru icq: 242-526-443

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Dynamic bitset library - compilation problem on windows (boost 1_37_0onwards)
by Aniket Bhat 13 May '09

13 May '09

I am seeing problems with msvc when compiling a simple code snippet that instantiates a dynamic_bitset with a uint64_t. The problem occurs when instantiating a template specialization for the resize function for uint64_t. There was a change made to the block_width_type typedef from an int in 1_36_0 to block_type in 1_37_0. This change seems to have broken support for uint64_t data-types on 32-bit windows systems or any other types which are bigger than size_t on a given platform. Code snippet: #include <boost/dynamic_bitset.hpp> #include <iostream> #if defined (__GNUC__) #if !defined (SUNOS_OS) typedef unsigned long long uint64_t; #endif #else typedef unsigned __int64 uint64_t; #endif typedef uint64_t myType; boost::dynamic_bitset<myType>::size_type foo() { unsigned int blockHandles(10); return (boost::dynamic_bitset<myType>::size_type )(blockHandles*sizeof(myType)*8); } int main(int argc,char**argv) { boost::dynamic_bitset<myType>::size_type t = foo(); boost::dynamic_bitset<myType> m_myBitSet; m_myBitSet.resize(12,false); } Compilation error: Compiling... TestBitSet.cpp c:\p3_dev_boost\common\lib\boost_1_39_0\boost\dynamic_bitset\dynamic_bitset.hpp(673) : error C2220: warning treated as error - no 'object' file generated c:\p3_dev_boost\common\lib\boost_1_39_0\boost\dynamic_bitset\dynamic_bitset.hpp(649) : while compiling class template member function 'void boost::dynamic_bitset<Block>::resize(boost::dynamic_bitset<Block>::size_type,bool)' with [ Block=myType ] c:\documents and settings\abhat\my documents\aniket\projects\dynamic_bitset\testbitset\testbitset.cpp(17) : see reference to class template instantiation 'boost::dynamic_bitset<Block>' being compiled with [ Block=myType ] c:\p3_dev_boost\common\lib\boost_1_39_0\boost\dynamic_bitset\dynamic_bitset.hpp(673) : warning C4244: 'initializing' : conversion from 'unsigned __int64' to 'const boost::dynamic_bitset<Block>::size_type', possible loss of data with [ Block=myType ] The resize function (dynamic_bitset.hpp:673) calls count_extra_bits() which returns a size_type instead of block_width_type resulting in possible loss of data. At all other places this function is called within the header, it returns a block_width_type. I am not sure if it has to return a size_type in this particular case for a specific reason? Thanks, Aniket.

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