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

[1.38.0] Regression test failures
by Beman Dawes 15 Jan '09

15 Jan '09

The reporting has been fixed and tests are starting to cycle. See http://beta.boost.org/development/tests/release/developer/summary.html There are failures on build, config, integer, ptr_container, serialization, and spirit. Please take a look if any of these are your library. Thanks, --Beman

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Are you a C++ guru - prove it here !
by Robert Ramey 15 Jan '09

15 Jan '09

I'm having problems with the following code below from boost/serialization/export.hpp compiling BOOST_CLASS_EXPORT_GUID(final, "final") results in the following error message on the gcc compilers. error: too few template-parameter-lists VC compilers don't complain about this. I've tried replacing ::boost::archive::detail::init_guid< T >::guid_initializer = \ with ::boost::archive::detail::init_guid< T >::guid_initializer< T> =\ But this doesn't help. Happy to get help from any C++ guru Robert Ramey template<typename T> class init_guid { static ::boost::archive::detail::guid_initializer<T> const & guid_initializer; }; } // namespace detail } // namespace archive } // namespace boost #define BOOST_CLASS_EXPORT_GUID(T, K) \ ::boost::archive::detail::guid_initializer< T > const & \ ::boost::archive::detail::init_guid< T >::guid_initializer = \ ::boost::serialization::singleton< \ ::boost::archive::detail::guid_initializer< T > \ >::get_mutable_instance().export_guid(K); \

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[LibrariesUnderConstruction] new gil io extension
by Christian Henning 14 Jan '09

14 Jan '09

Hi there, I just found out about the LibrariesUnderConstruction wiki. Is it possible to add an entry for the upcoming new boost::gil io extension. The current version is stable and can be used without any problems. In fact, I'm and other people are using the code in several projects. Right now, I'm working on the documentation. If possible please add the following entry. == Boost.GIL.IO == * '''Author(s): Christian Henning [mailto:chhenning-AT-gmail.com>''' * '''Version:''' * '''State:''' Stable * '''Last upload:''' 2009 Jan 14 * '''Links:''' [http://gil-contributions.googlecode.com/svn/trunk/gil_2] ( svn repository ) * '''Description:'''IO extension for boost::gil which allows reading and writing of/in image formats ( tiff, jpeg, ... ). Thanks, Christian

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Re: [boost] [LibrariesUnderConstruction] update of LibrariesUnderConstruction wiki page
by vicente.botet 14 Jan '09

14 Jan '09

Hi, The wiki page Libraries Under Construction contains now much more entries. Good trip, Vicente ----- Original Message ----- From: "vicente.botet" <vicente.botet(a)wanadoo.fr> To: <boost(a)lists.boost.org>; <boost-announce(a)lists.boost.org>; <boost-users(a)lists.boost.org> Sent: Sunday, December 07, 2008 5:50 PM Subject: [LibrariesUnderConstruction] new LibrariesUnderConstruction wiki page Hi, I have created a new wiki page containing some of the libraries under construction for Boost. You can access this page from the Boost Trac wiki https://svn.boost.org/trac/boost/wiki > Projects > Libraries Under Construction or directly https://svn.boost.org/trac/boost/wiki/LibrariesUnderConstruction The contents of this page is by nature incomplete and outdated. Please help to maintain this page updated by modifying it directly (if you have the rights) or posting on the Boost mailing lists boost(a)lists.boost.org or boost-users(a)lists.boost.org with the prefix [LibrariesUnderConstruction]. If you're the author of one of these libraries and desire that all or part of the information related to your library be removed or modified, please send a mail or you can do it directly if you prefer. If you're a library author and plan on submitting a library but don't know when it will be ready for review, and you want to include your library in this list, please add it directly (if you have the rights) or send a mail. If you're a library author and plan on submitting a library for review in the next 3-6 months, email Ron Garcia or John Phillips ("garcia at osl dot iu dot edu" and "phillips at mps dot ohio-state dot edu" respectively) a short description of your library and they will add it to the Review Wizard Report Libraries Under Construction section. HTH, Vicente

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[interthreads] Library under development v0.2
by vicente.botet 14 Jan '09

14 Jan '09

Hi, I have added the threader/joiner classes following the design of Kevlin Henney N1833 - Preliminary Threading Library Proposal for TR2 (http:/www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1883.pdf). I use the Boost.Futures library from Anthony (review ongoing) In addition and as a generalization of these classes I have started a framework working with asynchronous executors -AE (threader) and asynchronous completion tokens -ACT (joiner). The library include also an launcher (AE) associated to the unique_future (ACT) which is the equivalent of the thread_pool in N2276 - Thread Pools and Futures (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2276.html) With some minor changes in the ThreadPool library (review scheduled), the tp:pool can be seen as a AE and the tp::task as a ACT. The library allows also to fork several functions at the same time. The result of the fork_all operation is a fusion tuple of asynchronous completion token handles. The user can apply any fusion algorithm on this tuple as for example. To make common tasks easier the library provide some functors and some functions that are the result of applying these functors to the tuple using a fusion algorithm. Last the library provides also some functions like wait_for_all that forks all the functions and wait for the result of all of them and wait_for_any which works with functions that return the same type, and forks all the functions and wait for the first one. For the moment the AE/ACT framework is included it in Bosst.InterThreads library, but this is independent and can be included in an independent library (any suggestion for a name and a namespace?) The library is available at Boost Sandbox: https://svn.boost.org/svn/boost/sandbox/interthreads and Boost Vault: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=intert… Includes every thing on the Sandbox + Html documentation + Boost.Futures + Boost.ThreadPool adaptations I'd appreciate it if people could take a look, test it on their compiler and give me some feedback. It's not quite ready for formal review yet. Best regrads, Vicente _____________________ Vicente Juan Botet Escribá

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[mpl] sequence_tag
by Eric Niebler 14 Jan '09

14 Jan '09

A type is an mpl sequence if mpl::sequence_tag<T>::type is something other than mpl::non_sequence_tag. There are a few ways of hooking mpl::sequence_tag, but the easiest is for T to have a nested typedef named "tag". I find this unfortunate. Consider proto expression types, which, in addition to being nodes in expression trees, are also both fusion sequences and mpl sequences. A proto expression type has three tag types associated with it: 1) The Proto tag (e.g., proto::tag::plus), a nested typedef named "proto_tag" 2) The Fusion tag, a nested typedef named "fusion_tag" 3) The MPL tag I can't in good conscience use a nested typedef named "tag" for the MPL tag because that would lead to confusion. It would be nice if MPL had instead chosen the name "mpl_tag" for its tag type. It's not too late to make the change ... MPL could first look for "mpl_tag" before falling back on "tag". For now, I have chosen to specialize mpl::sequence_tag for the proto::expr type. This is an incomplete solution because types that extend proto::expr are not themselves automatically MPL sequences. Another solution might be to allow SFINAE on sequence_tag, like ... template<typename T, typename EnableIf = void> struct sequence_tag; That way I could partially specialize for proto expression types, like: template<typename T, typename enable_if<proto::is_expr<T> >::type> struct sequence_tag { ... Thoughts? FWIW, I'd prefer MPL to rename the nested tag typedef to "mpl_tag". -- Eric Niebler BoostPro Computing http://www.boostpro.com

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[linux drivers] Is it possible to use boost in a Linux driver?
by Sid Sacek 14 Jan '09

14 Jan '09

Does anybody know if it's possible to use boost within a Linux driver?

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[tr1] Help needed with Darwin port
by John Maddock 14 Jan '09

14 Jan '09

Can someone with access to various flavours of gcc-4.x on Darwin let me know what directory the glibc++ std lib headers are in? Currently Boost.TR1 is using #include <../c++/header_name> which is taken from STLPort's configuration, but is apparently causing regressions in the boost code, Thanks, John.

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[scope_exit] Doesn't included in Boost yet?
by Dmitriy Maksimov 14 Jan '09

14 Jan '09

Hi, I didn't found boost::scope_exit library in Boost 1.37 althougth the library approved in May 2008. Why? Kind regards, Dmitriy

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Re: [boost] [lexical_cast] A suggestion
by Andrew Troschinetz 14 Jan '09

14 Jan '09

Alexander Nasonov <alnsn <at> yandex.ru> writes: > This looks interesting but boost::optional<T> is already > InputStreamable: > #include <boost/optional/optional_io.hpp> This sounded really cool to me so I attempted a cursory hack to get this working. The only way I could figure out how to provide an override for optional<T> that never throws was to change detail::lexical_cast from a function to a struct to get partial template specialization. Maybe there is a better way, I'm new at this. It seems like there must be because I wound up with lots of almost- duplicated code. Here's the old familiar detail::lexical_cast, structified: And here's the optional<T> specialization: Initially this didn't work however. I traced it to what might be a bug in optional_io.hpp's insertion operator: if ( in.good() ) { int d = in.get(); if ( d == ' ' ) /* assuming a space in stream, what if there's not? */ { T x ; in >> x; v = x ; } else v = optional<T>() ; } return in; With the above insertion operator code, this would fail: istringstream si ("test"); optional<string> o; si >> o; assert (o); /* fails, would work if si were constructed with " test" instead */ That seems wrong to my thinking, but maybe there's a reason for the if (d == ' ') test? If the intent was to simply eat up spare white space, how about this instead: if (in) { T x; if (in >> std::ws >> x) v = x; else v = optional<T>(); } return in; Using that code in optional_io.hpp, and with the above changes, things work out just fine: int invalid_as_uint = -1; int valid_as_uint = 5; unsigned default_uint = 6; // Normal form, throws. try { unsigned i = lexical_cast<unsigned> (invalid_as_uint); cout << i << endl; } catch (const bad_lexical_cast&) { cout << "bad lexical cast error" << endl; } // Overload for lexical_cast<optional<T>>, does not throw. optional<unsigned> i = lexical_cast<optional<unsigned> > (invalid_as_uint); if (i) cout << *i << endl; else cout << "invalid return value" << endl; i = lexical_cast<optional<unsigned> > (valid_as_uint); if (i) cout << *i << endl; else cout << "invalid return value" << endl; Also, I would love to see a fallback style lexical_cast for the same reasons Neil already mentioned. -- Andrew Troschinetz

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