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Subject: Re: [boost] [type_traits] Rewrite and dependency free version
From: John Maddock (boost.regex_at_[hidden])
Date: 2015-01-15 03:58:48

> Testing gcc on Windows 7 with mingw and mingw64:
> Running type_traits tests passed with msvc-8.0, msvc-9.0, gcc-4.4.0,
> gcc-4.5.0, gcc-4.5.2, and gcc-4.9.2.
> Failed with gcc-4.3.0 with:
> "testing.capture-output
> ..\..\..\bin.v2\libs\type_traits\test\has_nothrow_assign_test.test\gcc-mingw-4.3.0\debug\
> ====== BEGIN OUTPUT ======
> has_nothrow_assign_test.cpp:204: The expression:
> "::boost::has_nothrow_assign<nothrow_construct_UDT>::value" had an
> invalid value (found 1, expected 0)"

I assume the current version has the same failure?

> In type_traits with gcc versions below 4 there are lots of failures of
> the order of:
> "gcc.compile.c++
> ..\..\..\bin.v2\libs\type_traits\test\is_virtual_base_of_test.test\gcc-mingw-3.4.5\debug\is_virtual_base_of_test.o
> ../../../boost/type_traits/is_virtual_base_of.hpp: In instantiation of
> `boost::detail::is_virtual_base_of_impl<Base, Derived,
> boost::integral_constant<bool, true>
> >::boost_type_traits_internal_struct_X':
> ../../../boost/type_traits/is_virtual_base_of.hpp:65: instantiated
> from `boost::detail::is_virtual_base_of_impl<Base, Derived,
> boost::integral_constant<bool, true> >'
> ../../../boost/type_traits/is_virtual_base_of.hpp:73: instantiated
> from `boost::detail::is_virtual_base_of_impl2<Base, Derived>'
> ../../../boost/type_traits/is_virtual_base_of.hpp:82: instantiated
> from `boost::is_virtual_base_of<Base, Derived>'"
> etc. Of course I can't imagine anyone still using those versions.

You missed out the error message! But again, does the current version
have the same failure?

> The function_types library depends on some type_traits implementation
> which is not in Version2, and tti uses function_types etc so tti fails.
>> * If anyone would like to help converting further traits all help would
>> be much appreciated.... Oh and the compiler requirements in the docs are
>> all wildly out of date too...
> Where are the compiler requirements for type_traits mentioned ?

There are out of date mentions in the docs - it all needs a *lot* of

If you mean "what are the requirements for this rewrite", then I don't
know yet... *should* be the same as the current code modulo the usual


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