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[mpl] cross product and gcc specific compiler error
by Josh Quigley 10 May '12

10 May '12

Hi, A question from the grossly uninformed: I grabbed an mpl cross product implementation (product_view) of this mailing list. It works fine in MSVC but fails in gcc: typedef boost::mpl::vector<float, double, long double> DecimalTypes; typedef boost::mpl::vector<int, unsigned int, long, unsigned long, long long, unsigned long long> IntegralTypes; typedef product_view<boost::mpl::vector<DecimalTypes, IntegralTypes> > EachDecimalWithEachIntegralT; BOOST_AUTO_TEST_CASE_TEMPLATE(MyTest, DecimalIntegralT, EachDecimalWithEachIntegralT) { { typename DecimalIntegralT::item1 r(1234567); // Fails on gcc: no type named ‘item0’ in ‘struct boost::mpl::v_item<long long unsigned int, boost::mpl::v_item<ext::decimal::decimal128, boost::mpl::vector0<mpl_::na>, 0>, 0> typename DecimalIntegralT::item0 d(r); BOOST_CHECK_EQUAL(static_cast<long long>(d), r); } } A complete listing is below. The thing that has me really stumped is the type exsits in MSVC, so I'm at a bit of loss of how to proceed debugging. // // LISTING // #include <boost/mpl/vector.hpp> #include <boost/mpl/if.hpp> #include <boost/mpl/at.hpp> #include <boost/mpl/copy.hpp> #include <boost/mpl/transform.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/function.hpp> #include <boost/mpl/vector.hpp> #include <boost/mpl/list.hpp> #include <boost/mpl/joint_view.hpp> #include <boost/test/unit_test.hpp> namespace detail { using boost::mpl::at_c; using boost::mpl::at; using boost::mpl::vector3; using boost::mpl::true_; using boost::mpl::false_; using boost::mpl::if_; using boost::mpl::next; using boost::mpl::bool_; using boost::mpl::front_inserter; using boost::mpl::clear; using boost::mpl::forward_iterator_tag; using boost::mpl::reverse_copy; using boost::mpl::transform1; using boost::mpl::deref; using boost::mpl::_1; using boost::mpl::_2; using boost::mpl::int_; using boost::mpl::fold; using boost::mpl::or_; using boost::mpl::nested_begin_end_tag; template<typename S, typename O> struct state_with_overflow { typedef S state; typedef O overflow; }; template<typename I3S> struct i3s_increment_inserter { template<typename I3, typename O> struct i3_ { typedef I3 i3; typedef O overflow; }; template<typename I3> struct incr_ { typedef typename next< typename at_c< I3, 1 >::type >::type next_; typedef bool_< boost::is_same< next_, typename at_c<I3,2>::type >::value > overflow_; typedef i3_< vector3< typename at_c<I3,0>::type, typename if_< overflow_, typename at_c<I3,0>::type, next_ >::type, typename at_c<I3,2>::type >, overflow_ > type; }; typedef front_inserter< typename clear<I3S>::type > base_; typedef state_with_overflow< typename base_::state, true_ > state; struct operation { template<typename S, typename I3> struct apply { typedef typename if_< typename S::overflow, typename incr_<I3>::type, i3_<I3,false_> >::type next_; typedef state_with_overflow< typename base_::operation::template apply< typename S::state, typename next_::i3 >::type, typename next_::overflow > type; }; }; }; template< typename SWO > struct product_iterator { private: typedef typename SWO::state I3S; public: typedef forward_iterator_tag category; typedef typename transform1< I3S, deref< at< _1, int_<1> > > >::type type; typedef product_iterator< typename reverse_copy< I3S, i3s_increment_inserter<I3S> >::type > next; }; template<typename S> struct product_view { private: typedef typename transform1< S, vector3< boost::mpl::begin<_1>, boost::mpl::begin<_1>, boost::mpl::end<_1> > >::type begin_impl; typedef typename fold< S, false_, or_< _1, boost::is_same< boost::mpl::begin<_2>, boost::mpl::end<_2> > // empty<_2> refuses to compile on MSVC 7.1 > >::type empty_result; public: typedef nested_begin_end_tag tag; typedef product_iterator< state_with_overflow< begin_impl, empty_result > > begin; typedef product_iterator< state_with_overflow< begin_impl, true_ > > end; }; } using detail::product_view; // typedef boost::mpl::vector<decimal32, decimal64, decimal128> DecimalTypes; // Original typedef boost::mpl::vector<float, double, long double> DecimalTypes; // for demonstration typedef boost::mpl::vector<int, unsigned int, long, unsigned long, long long, unsigned long long> IntegralTypes; typedef product_view<boost::mpl::vector<DecimalTypes, IntegralTypes> > EachDecimalWithEachIntegralT; BOOST_AUTO_TEST_CASE_TEMPLATE(MyTest, DecimalIntegralT, EachDecimalWithEachIntegralT) { { typename DecimalIntegralT::item1 r(1234567); // Fails on gcc: no type named ‘item0’ in ‘struct boost::mpl::v_item<long long unsigned int, boost::mpl::v_item<ext::decimal::decimal128, boost::mpl::vector0<mpl_::na>, 0>, 0> typename DecimalIntegralT::item0 d(r); BOOST_CHECK_EQUAL(static_cast<long long>(d), r); } }

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[coroutine]
by Christopher Kormanyos 10 May '12

10 May '12

Hello, I am checking out the fascinating work with Boost.Coroutine. Excellent! This is definitely paving the way for C++ threads. I have been looking for this kind of thing for quite some time now. I am mostly interested in adaptability, as I386 and the lot are mostly done. It's always the same game with the cooperative context switching. Time-after-time, you identify the clobbered registers after a cooperative yield, save them in a context structure and restore them after the yield. Then you deal with the stacks. OK, fine. But how can you approach the dream of generic context switching? So you know, here I am. I would want Boost.Context for numerous GCC targets: Atmel AVR, Renesas V850, Renesas RL78, Cortex-M3/4. And the list goes on, as I use numerous embedded processors. The compiler's calling convention is poorly documented at best. And various compiler vendors may or may not coordinate the calling convention among each other. Can the documentation of Boost.Coroutine aid in adaptation in any way? Or is this simply beyond the present scope of the proposed Boost.Coroutine? * Is there any documentation regarding the context switch? * Are you specifically targeting preemptive yields? * If so, is the compiler's calling convention taken into account? * Can the remarkable Boost.Coroutine be adapted to other CPUs? * How? * Is Coroutine meant to be compatible with std::this_thread::yield(), etc? * Can the user select the stack sizes? * How? Thank you. And keep up the great work! Best regards, Chris.

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[coroutine] request for review manager
by Oliver Kowalke 10 May '12

10 May '12

Hi, I want to ask who wants to be the review manager for boost.coroutine? The documentation is updated and available at: http://ok73.ok.funpic.de/boost/libs/coroutine/doc/html/index.html best regards, Oliver

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[serialization] portable_binary_archive using shared lib
by Renato Tegon Forti 09 May '12

09 May '12

Hi, I want use portable_binary_archive, but using shared link on Windows! Have any way? Thanks

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[exception] patches for a few testing-related issues
by David Deakins 09 May '12

09 May '12

Hi Emil, I have opened two Trac tickets (6877 and 6878) related to what I believe is a bug in exception_ptr_test.cpp and also for a minor change to the testing jamfile that will allow some of the thread-dependent tests to run on platforms that do not have automatic thread-specific-storage cleanup implemented (WinCE falls in this category). Are you ok with me applying these patches? Thanks, -Dave

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enable_if question
by John Maddock 08 May '12

08 May '12

Folks I'm having some difficulties understanding the subtleties of enable_if, consider: using namespace boost; template <unsigned B> struct dummy {}; template <unsigned B, class Integer> typename boost::enable_if<mpl::and_<is_signed<Integer>, mpl::bool_<(sizeof(Integer) <= sizeof(long))> > >::type bar(dummy<B>&, const Integer&) { } template <unsigned B, class Integer> typename boost::enable_if<mpl::and_<is_unsigned<Integer>, mpl::bool_<(sizeof(Integer) <= sizeof(long))> > >::type bar(dummy<B>&, const Integer&) { } Then calling: dummy<2> d; bar(d, 2); Leads to an ambiguity between the two overloads (both gcc and VC++10), how can that be? However, changing the condition to: template <unsigned B, class Integer> typename boost::enable_if<mpl::and_<is_signed<Integer>, mpl::bool_<(B || !B) && (sizeof(Integer) <= sizeof(long))> > >::type bar(dummy<B>&, const Integer&) { } template <unsigned B, class Integer> typename boost::enable_if<mpl::and_<is_unsigned<Integer>, mpl::bool_<(B || !B) && (sizeof(Integer) <= sizeof(long))> > >::type bar(dummy<B>&, const Integer&) { } "fixes" things. But this fix isn't always possible. Thoughts? Thanks, John.

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[preprocessor] Chaos: Auto macros incorrectly deduces the recursion state
by paul Fultz 08 May '12

08 May '12

Hello, I am not sure if this is the most appropriate place to post this, but I do know the author frequents this mailing list often. Well, when I run this code: #define FIXED(s, n, text) text #define TTP(s, n, id) \ template< \ CHAOS_PP_AUTO_ENUM( \ CHAOS_PP_INC(n), FIXED, class \ ) \ > class id ## n \ /**/ CHAOS_PP_AUTO_ENUM(3, TTP, T) // template<class> class T0, // template<class, class> class T1, // template<class, class, class> class T2 It expands to: template< CHAOS_IP_AUTO_ENUM_1( 1, FIXED, class ) > class T0 , template< CHAOS_IP_AUTO_ENUM_1( 2, FIXED, class ) > class T1 , template< CHAOS_IP_AUTO_ENUM_1( 3, FIXED, class ) > class T2 Showing CHAOS_IP_AUTO_ENUM_1 is incorrect, and its why it won't expand since its trying to be expanded recursively. It should be CHAOS_IP_AUTO_ENUM_2 instead. I'm not sure why it incorrectly deduces the recursion state. TTP is not a deferred expression. Any ideas? Thanks, Paul Fultz II

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Aspen Meadows Resort suite available for up to 4 nights for C++Now Conference
by Pdruck 08 May '12

08 May '12

Hi. I reserved a suite at Aspen Meadows Resort for 4 nights, for the C++Now conference; Sunday night, May 13 – Wed night, May 16, leaving Thurs. May 17. But due to last minute pressing events in the office, I have to cancel my registration. Propose to switch my reservation to whomever might be attending. Win-win. I don’t lose a heft cancellation fee. You get a beautiful suite (having been there previously) and conveniently located to the conference at Physics Center. Regards. Phil

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Iterator Range and operator==
by Olaf van der Spek 08 May '12

08 May '12

Hi, What do you expect this code to do? Is b true or false? And why? Is this expected behaviour? #include <boost/range/iterator_range.hpp> #include <string> int main() { std::string s = "Olaf"; boost::iterator_range<std::string::iterator> r(s); bool a = r == s; bool b = r == "Olaf"; assert(a); assert(b); return 0; } -- Olaf

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[bind] variant arg list template functions could have a forward declaration as doc & coding suggeustion
by Huang Huan 08 May '12

08 May '12

Hi all, Before I do some change, no suggestion when I coding with Boost.Bind. This is a big disadvantage for learning & using. Variant arg list template functions as follow are there in so many boost code file. // template<class F, class A1, ... class An> // X foo(F f, A1 a1, ... An an); template<class F> X foo(F f) { ... } template<class F, class A1> X foo(F f, A1 a1) { ... } template<class F, class A1, class A2> X foo(F f, A1 a1, A2 a1) { ... } ... Some code like the comment, the forward declaration could be good doc & coding suggestion, such as following: template<class F /*, class A1, ... class An */> X foo(F f /*, A1 a1, ... An an */); OR template<class F, class A1, class A2 /*, ... */> X foo(F f, A1 a1, A2 a2, ... ); OR template<class F /*... */> // may no cxx11 X foo(F f , ... ); This may like BOOST_CONTAINERS_PERFECT_FORWARDING Becase of the template grammar, this forward declaration has no implementation. The code is ONLY for coding suggestion & doc. As an example [boost][bind] When I write the code boost::bind( _ ) I want the suggestions as follow ______________________________________________ | [1 of 3] _bi::bind_t<_bi::unspecified, F, L> bind(F f, ...) | |_____________________________________________| A more difficulty is boost bind has a BOOST_BIND for redefine the name. my patch as follow: =================================================================== --- bind.hpp (revision 77278) +++ bind.hpp (working copy) @@ -1289,6 +1289,17 @@ #ifndef BOOST_BIND #define BOOST_BIND bind + +template<class R, class F, class L> + _bi::bind_t<R, F, L> + bind(F f, ...); +template<class R, class F, class L> + _bi::bind_t<R, F, L> + bind(boost::type<R>, F f, ...); +template<class F, class L> + _bi::bind_t<_bi::unspecified, F, L> + bind(F f, ...); + #endif // generic function objects

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