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Any problems if I apply the patch in ticket #4377
by Marshall Clow 28 Jun '10

28 Jun '10

Looks ok to me.... https://svn.boost.org/trac/boost/ticket/4377 -- Marshall

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[math] common_factor template parameters
by vicente.botet 28 Jun '10

28 Jun '10

Hi, static_gcc and static_lcm have unsigned long parameters. template < unsigned long Value1, unsigned long Value2 > struct boost::math::static_gcd; Could these be changed to uintmax_t? Is there any deep reason to don't define them for singed integers (intmax_t) also? Thanks, _____________________ Vicente Juan Botet Escribá http://viboes.blogspot.com/

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[mini-review] Update of Boost.Assign (13th-19th of June)
by Thorsten Ottosen 28 Jun '10

28 Jun '10

Dear Boost Developers and Users, Erwann Rogard has implemented an update to Boost.Assign which we shall evaluate during the next week. His extensions allows one to write code like the following: (A) A list of references (to temporaries, in this example): boost::array<int,8> a = cref_csv( 1,5,3,4,2,9,0,7 ) (B) Chained ranges: vector<int> v = vector<int>( 3,1 ) && vector<int>( 3,2 ); If you have comments and suggestions about these new features, please submit a small review or voice your oppinion on the Boost developer list. If you have other feedback for Boost.Assign, now would be a good time to mention them too. If you submit a review, please follow the guidelines here: http://www.boost.org/community/reviews.html#Comments To access the new docs, please see https://svn.boost.org/svn/boost/sandbox/statistics/support/libs/assign/doc/… To access the new code, please see https://svn.boost.org/svn/boost/sandbox/statistics/support/boost/assign/ best regards Thorsten Ottosen, Review Manager

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[typeof] 2 questions
by Eric Niebler 27 Jun '10

27 Jun '10

1) Some compilers don't support typeof in any form, even emulated. From looking at typeof.hpp, it looks like just #include'ing typeof.hpp on those compilers results in a hard error. I'd like a way to test whether typeof is supported and use it if so, otherwise do something else. How can I do that? 2) I can't find "decltype" by grepping the typeof code. Why doesn't typeof use the decltype keyword on compilers that support it? And I lied. I have another question. How expensive at compile-time is emulated typeof? TIA, -- Eric Niebler BoostPro Computing http://www.boostpro.com

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[program_options] error reporting from custom validators
by Monty Taylor 27 Jun '10

27 Jun '10

Hi! I've been working on using notifier() to register a custom validator for an option. If the validator doesn't pass, it throws invalid_option_value. The issue I'm running in to though is that I do not have an context to report which option had a problem- I'm actually also really just abusing the notifier system as well, as I throw invalid_option_value with a descriptive message instead of just the option value. If I pass in an already bogus value, such as passing in a string to an int option, I get something like this: Error processing options: in option 'connect_timeout': invalid option value 'eggs' So it seems there are places where the code is validating options (seemingly just from any_cast) with context of which option is being validated. Is there some place I'm missing to hook a validator in where throwing an exception would properly pick up option name context? I saw this comment: /* We call validate so that if user provided a validator for class T, we use it even when parsing vector<T>. */ What I'd really love would be if I could call something like validator(some_validator).validator(some_other_validator), and that those would be passed some sort of context. Specifically, in the code we're working on replacing, it's quite easy to specify a min and max value for an integer option, and I'm trying to figure out a good way to keep this without requiring folks to write a completely independent notifier function for each option that emits its own error message. Any thoughts on where I might want to go with this?

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[typeof] message.hpp and BOOST_TYPEOF_SILENT
by vicente.botet 27 Jun '10

27 Jun '10

Hi, I'm unable to find where message.hpp and BOOST_TYPEOF_SILENT are documented. Could this be added to the documentation is missing, and otherwise, could you point me where it is? Thanks, _____________________ Vicente Juan Botet Escribá http://viboes.blogspot.com/

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iterator_category> algorithm selection with cast operator
by gzp 26 Jun '10

26 Jun '10

Hello, I've read the article of ranges vs. iterators from Andrei Alexandrescu and I've start to implement something similar and wanted to extend the idea to 2D grids (popFront, front, popLine). OK, I now s/g similar can be achieved using iterators(ranges) returning iterators(ranges) as the current item, I was just simple experimenting. Using the iterator_category concept empty structs are used to check, select functions at compile time. struct A {}; struct B : A {} void foo( A ) { alg1... } void foo( B ) { alg2... specialized for B } template<typename T> void foofoo( T ){ foo( getCategory<T>() ); } My first idea was to use multiple inheritance, but it result error (ambiguous call) struct A {}; struct B : A {}; struct A2 : A {}; struct B2 : A2, B {}; void foo( A ) { alg1... } void foo( B ) { alg2... specialized for B } void foo( A2 ) { alg3... specialized for A2 } void g() { B2 b; f(b); } // error: is it f(B) or f(A2) Than I've used cast operators and inheritance stating that, a B2 is mainly an A2 and secondly a B: struct A {}; struct B : A {}; struct A2 : A {}; struct B2 : A2 { operator B() { return B(); } }; void foo( A ) { alg1... } void foo( B ) { alg2... specialized for B } void foo( A2 ) { alg3... specialized for A2 } void g() { B2 b; f(b); } // shall call f(A2) So my question is that, is it a working method, or the whole concept is wrong ? Has anyone used something similar ? If so, is there some sample codes/results? Thank you, Gzp -- View this message in context: http://old.nabble.com/iterator_category%3E-algorithm-selection-with-cast-op… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Assertion `slot->m_to_python == 0' failed in when trying to expose custom iterator
by Yongning Zhu 25 Jun '10

25 Jun '10

Hi, I am following a tutorial to expose a custom iterator to python, The iterator was used in C++ by for(T_ITERATOR it();it.Valid();it.Next()){ T_VALUE v=it.Value(); } And I wrote the following wrapper: template<class Klass, class KlassIter> struct iterator_wrappers { static Klass next(KlassIter& o) { o.Next(); Klass result = o.Value(); if (!o.Valid()) { PyErr_SetString(PyExc_StopIteration, "No more data."); boost::python::throw_error_already_set(); } return result; } static void wrap(const char* python_name) { //using namespace boost::python; class_<KlassIter>(python_name, init<>())//no_init .def("next", next) .def("__iter__", pass_through) ; } }; and expose it by iterator_wrappers<T_VALUE,T_ITERATOR>().wrap("t_iterator"); It compiles but when I am importing the module in python, there is an error saying: python: ../../../../libs/python/src/converter/registry.cpp:212: void boost::python::converter::registry::insert(PyObject* (*)(const void*), boost::python::type_info, const PyTypeObject* (*)()): Assertion `slot->m_to_python == 0' failed. Aborted Could some one please help me? Thanks a lot! Yong

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[graph] ambiguity for 'tie' VC10
by Andreas Fabri 25 Jun '10

25 Jun '10

Hello, For Windows7 VC10 64 bit, boost_1_43_0 the following code produces an error message #include <tuple> #include <boost/graph/adjacency_list.hpp> typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::undirectedS > G; int main() { G g1; G g2(g1); return 0; } C:\boost\boost_1_43_0\boost/graph/detail/adjacency_list.hpp(2157) : error C2668: 'boost::tuples::tie' : ambiguous call to overloaded function C:\boost\boost_1_43_0\boost/tuple/detail/tuple_basic.hpp(889): could be 'boost::tuples::tuple<T0,T1,T2,T3,T4,T5,T6,T7,T8,T9> boost::tuples::tie<boost::detail::undirected_edge_iter<EdgeIter,EdgeDescriptor,Difference>,boost::detail::undirected_edge_iter<EdgeIter,EdgeDescriptor,Difference>>(boost::detail::undirected_edge_iter<EdgeIter,EdgeDescriptor,Difference> &,boost::detail::undirected_edge_iter<EdgeIter,EdgeDescriptor,Difference> &)' .... OR C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\INCLUDE\xxtuple1(34): or 'std::tr1::tuple<_Arg0,_Arg1,_Arg2,_Arg3,_Arg4,_Arg5,_Arg6,_Arg7,_Arg8,_Arg9> std::tr1::tie<boost::detail::undirected_edge_iter<EdgeIter,EdgeDescriptor,Difference>,boost::detail::undirected_edge_iter<EdgeIter,EdgeDescriptor,Difference>>(boost::detail::undirected_edge_iter<EdgeIter,EdgeDescriptor,Difference> &,boost::detail::undirected_edge_iter<EdgeIter,EdgeDescriptor,Difference> &)' [found using argument-dependent lookup] Best regards, andreas fabri

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Re: [boost] boost [msm] deferring event by base type
by Christophe Henry 25 Jun '10

25 Jun '10

> I'm now using Row and Defer functor I have now an other problem whit the : > > void defer_event(Event const& e) > { > // to call this function, you need either a state with a > deferred_events typedef > // or that the fsm provides the activate_deferred_events typedef > BOOST_MPL_ASSERT(( has_fsm_deferred_events<library_sm> )); > execute_return (library_sm::*pf) (Event const& evt)= > &library_sm::process_event; > Event temp (e); > ::boost::function<execute_return ()> f= ::boost::bind(pf, this,temp); > post_deferred_event(f); > } > > actually it tries to instantiate the base class ( Event temp (e); ) > but in my case the base class is an abstract class -> compiler error; > and after deferring I want to dispatch the original derived event not > the copy constructed base class instance of the event. What you get is a slicing. The Defer functor works like any action, meaning that the type of the event is encoded in the transition. If you consider a transition: a_row < Stopped , play , Playing , &p::start_playback > and an action: void start_playback(play const&) The type of the event in the action is the one defined in the transition. So what defer_event gets (from Defer) is the type defined in the transition, in your case the base event. It's harder to spot than a vector<base> but about the same. A solution would be to have msm's process_event reinterpret_cast action signature. I will take it into my feature list but probably not at the top as I consider the feature as only nice to have. In the meantime, I, like Juraj, would also suggest you to pimpl your data (with or without a shared_ptr) or define one entry inside deferred_events for every derived event. Regards, Christophe

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