Sorry for top posting... Yes, the __rw_is_convertible_impl<T,U>::_C_make should probably be changed to return __rw_remove_cv<_TypeT>::type (probably with a typedef). We should probably add a case for this in the 20.meta.rel.cpp test also.
I'm on vacation today otherwise I'd make the necessary changes myself. Travis -----Original Message----- From: Martin Sebor on behalf of Martin Sebor Sent: Thu 6/26/2008 10:12 PM To: dev@stdcxx.apache.org Subject: Re: implementation of Unary Traits Eric Lemings wrote: > > >> -----Original Message----- >> From: Martin Sebor [mailto:[EMAIL PROTECTED] On Behalf Of Martin Sebor >> Sent: Thursday, June 26, 2008 5:45 PM >> To: dev@stdcxx.apache.org >> Subject: implementation of Unary Traits >> >> The implementation of Unary Traits (e.g., is_void) uses explicit >> specialization on all four combinations of cv-qualifiers for each >> trait (plain, const, volatile, and const volatile). I'm wondering >> if the alternative approach of stripping the qualifiers before >> "dispatching" to just one explicit specialization has been >> considered. The potential advantage of this approach is fewer >> declarations, smaller translation units, and thus (presumably) >> faster compilation. > > Though I'm using a relational (binary) type trait, I'm getting warnings > because the cv-qualifiers are not being stripped. A test case is always helpful: #include <type_traits> int main () { return !std::is_convertible<const int, int>::value; } Seems like is_convertible might need to strip top-level cv qualifiers from the types. What do you think, Travis? Martin > > gcc -c -I/work/stdcxx/branches/4.3.x/include/ansi -D_RWSTDDEBUG > -pthread -I/work/stdcxx/branches/4.3.x/include > -I/build/stdcxx-4.3.x-15D/include > -I/work/stdcxx/branches/4.3.x/tests/include -std=gnu++0x > -D_RWSTD_EXT_CXX_0X -W -Wall -Wcast-qual -Winline -Wshadow > -Wwrite-strings -Wno-long-long -Wcast-align > /work/stdcxx/branches/4.3.x/tests/utilities/20.tuple.cnstr.cpp > /work/stdcxx/branches/4.3.x/include/rw/_meta_rel.h: In > instantiation of '__rw::__rw_is_convertible_impl<const int, int>': > /work/stdcxx/branches/4.3.x/include/rw/_meta_rel.h:93: > instantiated from '__rw::__rw_is_convertible_3<const int, int, false, > false>' > /work/stdcxx/branches/4.3.x/include/rw/_meta_rel.h:122: > instantiated from '__rw::__rw_is_convertible_2<const int, int, false>' > /work/stdcxx/branches/4.3.x/include/rw/_meta_rel.h:145: > instantiated from '__rw::__rw_is_convertible_1<const int, int, false, > false>' > /work/stdcxx/branches/4.3.x/include/rw/_meta_rel.h:163: > instantiated from '__rw::__rw_is_convertible<const int, int>' > /work/stdcxx/branches/4.3.x/include/tuple:68: instantiated > from 'std::tuple<const int>::_C_is_compatible<int>' > /work/stdcxx/branches/4.3.x/include/tuple:123: instantiated > from 'std::tuple<_Types>::tuple(_TypesU&& ...) [with _TypesU = int, > _TypesT = const int]' > > /work/stdcxx/branches/4.3.x/tests/utilities/20.tuple.cnstr.cpp:103: > instantiated from here > /work/stdcxx/branches/4.3.x/include/rw/_meta_rel.h:77: warning: > type qualifiers ignored on function return type > > Brad.
