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Always have a definition for each traits member, even if it can't be properly

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deduced. These will be incomplete types in some cases (undefined<void>), but it
helps suppress MSVC errors elsewhere


[SVN r9064]
This commit is contained in:
Dave Abrahams
2001-02-10 00:05:17 +00:00
parent 2947fb7051
commit 08a2ab3fe6
1 changed files with 17 additions and 2 deletions
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19
include/boost/detail/iterator.hpp
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@ -23,6 +23,10 @@
// See http://www.boost.org for most recent version including documentation. // See http://www.boost.org for most recent version including documentation.
// Revision History // Revision History
// 09 Feb 2001 - Always have a definition for each traits member, even if it
// can't be properly deduced. These will be incomplete types in
// some cases (undefined<void>), but it helps suppress MSVC errors
// elsewhere (David Abrahams)
// 07 Feb 2001 - Support for more of the traits members where possible, making // 07 Feb 2001 - Support for more of the traits members where possible, making
// this useful as a replacement for std::iterator_traits<T> when // this useful as a replacement for std::iterator_traits<T> when
// used as a default template parameter. // used as a default template parameter.
@ -63,6 +67,7 @@ using std::distance;
// Workarounds for less-capable implementations // Workarounds for less-capable implementations
template <bool is_ptr> struct iterator_traits_select; template <bool is_ptr> struct iterator_traits_select;
template <class T> struct undefined;
template <> struct iterator_traits_select<true> template <> struct iterator_traits_select<true>
{ {
template <class Ptr> template <class Ptr>
@ -70,6 +75,14 @@ template <> struct iterator_traits_select<true>
{ {
typedef std::ptrdiff_t difference_type; typedef std::ptrdiff_t difference_type;
typedef std::random_access_iterator_tag iterator_category; typedef std::random_access_iterator_tag iterator_category;
#ifdef BOOST_MSVC
// Keeps MSVC happy under certain circumstances. It seems class template default
// arguments are partly instantiated even when not used when the class template
// is the return type of a function template.
typedef undefined<void> value_type;
typedef undefined<void> pointer;
typedef undefined<void> reference;
#endif
}; };
}; };
@ -132,8 +145,6 @@ struct bad_output_iterator_select<false>
}; };
# endif # endif
template <class T> struct undefined;
template <> struct iterator_traits_select<false> template <> struct iterator_traits_select<false>
{ {
template <class Iterator> template <class Iterator>
@ -143,6 +154,10 @@ template <> struct iterator_traits_select<false>
# if defined(BOOST_MSVC) && !defined(__SGI_STL_PORT) # if defined(BOOST_MSVC) && !defined(__SGI_STL_PORT)
typedef typename Iterator::distance_type difference_type; typedef typename Iterator::distance_type difference_type;
typedef typename Iterator::value_type value_type; typedef typename Iterator::value_type value_type;
#ifdef BOOST_MSVC // Keeps MSVC happy under certain circumstances
typedef undefined<void> pointer;
typedef undefined<void> reference;
#endif
# elif !defined(BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION) # elif !defined(BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION)
typedef typename Iterator::difference_type difference_type; typedef typename Iterator::difference_type difference_type;
typedef typename Iterator::value_type value_type; typedef typename Iterator::value_type value_type;