Remove __cplusplus > 201703L checks that are redundant when used
alongside __glibcxx_concepts checks, because <version> already
guarantees that __glibcxx_concepts is only defined for C++20 and later.
Prefer to check __glibcxx_ranges for features such as move_sentinel that
were added by the One Ranges proposal (P0896R4), or for features which
depend on other components introduced by that proposal.
But prefer to check __glibcxx_concepts for constraints that only depend
on requires-clauses and concepts defined in <concepts>, even if those
constraints were added by the Ranges proposal (e.g. the constraints on
non-member operators for move_iterator).
Prefer #ifdef to #if when just testing for the presence of __glibcxx_foo
macros with caring about their value.
Also add/tweak some Doxygen comments.
libstdc++-v3/ChangeLog:
* include/bits/stl_iterator.h: Make use of feature test macros
more consistent. Improve doxygen comments.
---
Tested x86_64-linux. Pushed to trunk.
libstdc++-v3/include/bits/stl_iterator.h | 102 ++++++++++++-----------
1 file changed, 55 insertions(+), 47 deletions(-)
diff --git a/libstdc++-v3/include/bits/stl_iterator.h
b/libstdc++-v3/include/bits/stl_iterator.h
index 5962ab3af3b..8c86cb214b2 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -91,7 +91,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* @{
*/
-#if __glibcxx_concepts
+#ifdef __glibcxx_concepts
+ /// @cond undocumented
namespace __detail
{
// Weaken iterator_category _Cat to _Limit if it is derived from that,
@@ -100,6 +101,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
using __clamp_iter_cat
= __conditional_t<derived_from<_Cat, _Limit>, _Limit, _Otherwise>;
}
+ /// @endcond
#endif
// Ignore warnings about std::iterator.
@@ -136,7 +138,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Iter>
friend class reverse_iterator;
-#if __glibcxx_concepts
+#ifdef __glibcxx_concepts
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3435. three_way_comparable_with<reverse_iterator<int*>, [...]>
template<typename _Iter>
@@ -152,7 +154,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
public:
typedef _Iterator iterator_type;
typedef typename __traits_type::pointer pointer;
-#if ! __glibcxx_concepts
+#ifndef __glibcxx_concepts
typedef typename __traits_type::difference_type difference_type;
typedef typename __traits_type::reference reference;
#else
@@ -208,7 +210,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* underlying %iterator can be converted to the type of @c current.
*/
template<typename _Iter>
-#if __glibcxx_concepts
+#ifdef __glibcxx_concepts
requires __convertible<_Iter>
#endif
_GLIBCXX17_CONSTEXPR
@@ -219,10 +221,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#if __cplusplus >= 201103L
template<typename _Iter>
-#if __glibcxx_concepts
+# ifdef __glibcxx_concepts
requires __convertible<_Iter>
&& assignable_from<_Iterator&, const _Iter&>
-#endif
+# endif
_GLIBCXX17_CONSTEXPR
reverse_iterator&
operator=(const reverse_iterator<_Iter>& __x)
@@ -231,7 +233,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
current = __x.current;
return *this;
}
-#endif
+#endif // C++11
/**
* @return @c current, the %iterator used for underlying work.
@@ -268,7 +270,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_GLIBCXX_NODISCARD
_GLIBCXX17_CONSTEXPR pointer
operator->() const
-#if __cplusplus > 201703L && __cpp_concepts >= 201907L
+#ifdef __glibcxx_concepts
requires is_pointer_v<_Iterator>
|| requires(const _Iterator __i) { __i.operator->(); }
#endif
@@ -386,7 +388,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
operator[](difference_type __n) const
{ return *(*this + __n); }
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_ranges
[[nodiscard]]
friend constexpr iter_rvalue_reference_t<_Iterator>
iter_move(const reverse_iterator& __i)
@@ -410,7 +412,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
auto __ytmp = __y.base();
ranges::iter_swap(--__xtmp, --__ytmp);
}
-#endif
+#endif // ranges
private:
template<typename _Tp>
@@ -434,7 +436,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* iterators.
*
*/
-#if __cplusplus <= 201703L || ! defined __glibcxx_concepts
+#ifndef __glibcxx_concepts
template<typename _Iterator>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
@@ -645,7 +647,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
make_reverse_iterator(_Iterator __i)
{ return reverse_iterator<_Iterator>(__i); }
-# if __cplusplus > 201703L && defined __glibcxx_concepts
+# ifdef __glibcxx_ranges
template<typename _Iterator1, typename _Iterator2>
requires (!sized_sentinel_for<_Iterator1, _Iterator2>)
inline constexpr bool
@@ -681,7 +683,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
public:
/// A nested typedef for the type of whatever container you used.
typedef _Container container_type;
-#if __cplusplus > 201703L
+#ifdef __glibcxx_ranges
using difference_type = ptrdiff_t;
#endif
@@ -782,7 +784,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
public:
/// A nested typedef for the type of whatever container you used.
typedef _Container container_type;
-#if __cplusplus > 201703L
+#ifdef __glibcxx_ranges
using difference_type = ptrdiff_t;
#endif
@@ -881,7 +883,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
class insert_iterator
: public iterator<output_iterator_tag, void, void, void, void>
{
-#if __cplusplus > 201703L && defined __glibcxx_concepts
+#ifdef __glibcxx_ranges
using _Iter = std::__detail::__range_iter_t<_Container>;
#else
typedef typename _Container::iterator _Iter;
@@ -894,7 +896,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
/// A nested typedef for the type of whatever container you used.
typedef _Container container_type;
-#if __cplusplus > 201703L && defined __glibcxx_concepts
+#ifdef __glibcxx_ranges
using difference_type = ptrdiff_t;
#endif
@@ -990,7 +992,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* template parameter deduction, making the compiler match the correct
* types for you.
*/
-#if __cplusplus > 201703L && defined __glibcxx_concepts
+#ifdef __glibcxx_ranges
template<typename _Container>
[[nodiscard]]
constexpr insert_iterator<_Container>
@@ -1042,7 +1044,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
typedef typename __traits_type::reference reference;
typedef typename __traits_type::pointer pointer;
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_ranges
using iterator_concept = std::__detail::__iter_concept<_Iterator>;
#endif
@@ -1168,7 +1170,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// provide overloads whose operands are of the same type. Can someone
// remind me what generic programming is about? -- Gaby
-#if __cpp_lib_three_way_comparison
+#ifdef __cpp_lib_three_way_comparison
template<typename _IteratorL, typename _IteratorR, typename _Container>
[[nodiscard, __gnu__::__always_inline__]]
constexpr bool
@@ -1354,7 +1356,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* @{
*/
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_ranges
+ /// A sentinel adaptor for use with std::move_iterator.
template<semiregular _Sent>
class move_sentinel
{
@@ -1394,11 +1397,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
private:
_Sent _M_last;
};
-#endif // C++20
+ /// @cond undocumented
namespace __detail
{
-#if __cplusplus > 201703L && __glibcxx_concepts
template<typename _Iterator>
struct __move_iter_cat
{ };
@@ -1411,11 +1413,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
= __clamp_iter_cat<__iter_category_t<_Iterator>,
random_access_iterator_tag>;
};
-#endif
}
+ /// @endcond
+#endif // ranges
// 24.4.3 Move iterators
- /**
+ /** @brief An iterator adaptor that yields an rvalue reference.
+ *
* Class template move_iterator is an iterator adapter with the same
* behavior as the underlying iterator except that its dereference
* operator implicitly converts the value returned by the underlying
@@ -1425,21 +1429,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*/
template<typename _Iterator>
class move_iterator
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_ranges
: public __detail::__move_iter_cat<_Iterator>
#endif
{
_Iterator _M_current;
using __traits_type = iterator_traits<_Iterator>;
-#if ! (__cplusplus > 201703L && __glibcxx_concepts)
+#ifndef __glibcxx_ranges
using __base_ref = typename __traits_type::reference;
#endif
template<typename _Iter2>
friend class move_iterator;
-#if __glibcxx_concepts // C++20 && concepts
+#ifdef __glibcxx_concepts // C++20 && concepts
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3435. three_way_comparable_with<reverse_iterator<int*>, [...]>
template<typename _Iter2>
@@ -1447,7 +1451,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
&& convertible_to<const _Iter2&, _Iterator>;
#endif
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_ranges
static auto
_S_iter_concept()
{
@@ -1496,7 +1500,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: _M_current(std::move(__i)) { }
template<typename _Iter>
-#if __glibcxx_concepts
+#ifdef __glibcxx_concepts
requires __convertible<_Iter>
#endif
_GLIBCXX17_CONSTEXPR
@@ -1504,7 +1508,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: _M_current(__i._M_current) { }
template<typename _Iter>
-#if __glibcxx_concepts
+#ifdef __glibcxx_concepts
requires __convertible<_Iter>
&& assignable_from<_Iterator&, const _Iter&>
#endif
@@ -1535,7 +1539,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
[[__nodiscard__]]
_GLIBCXX17_CONSTEXPR reference
operator*() const
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_ranges
{ return ranges::iter_move(_M_current); }
#else
{ return static_cast<reference>(*_M_current); }
@@ -1561,7 +1565,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __tmp;
}
-#if __glibcxx_concepts
+#ifdef __glibcxx_concepts
constexpr void
operator++(int) requires (!forward_iterator<_Iterator>)
{ ++_M_current; }
@@ -1609,13 +1613,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
[[__nodiscard__]]
_GLIBCXX17_CONSTEXPR reference
operator[](difference_type __n) const
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_ranges
{ return ranges::iter_move(_M_current + __n); }
#else
{ return std::move(_M_current[__n]); }
#endif
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_ranges
template<sentinel_for<_Iterator> _Sent>
[[nodiscard]]
friend constexpr bool
@@ -1653,12 +1657,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline _GLIBCXX17_CONSTEXPR bool
operator==(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_concepts
requires requires { { __x.base() == __y.base() } -> convertible_to<bool>; }
#endif
{ return __x.base() == __y.base(); }
-#if __cpp_lib_three_way_comparison
+#ifdef __cpp_lib_three_way_comparison
template<typename _IteratorL,
three_way_comparable_with<_IteratorL> _IteratorR>
[[__nodiscard__]]
@@ -1680,7 +1684,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline _GLIBCXX17_CONSTEXPR bool
operator<(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_concepts
requires requires { { __x.base() < __y.base() } -> convertible_to<bool>; }
#endif
{ return __x.base() < __y.base(); }
@@ -1690,7 +1694,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline _GLIBCXX17_CONSTEXPR bool
operator<=(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_concepts
requires requires { { __y.base() < __x.base() } -> convertible_to<bool>; }
#endif
{ return !(__y < __x); }
@@ -1700,7 +1704,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline _GLIBCXX17_CONSTEXPR bool
operator>(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_concepts
requires requires { { __y.base() < __x.base() } -> convertible_to<bool>; }
#endif
{ return __y < __x; }
@@ -1710,7 +1714,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline _GLIBCXX17_CONSTEXPR bool
operator>=(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_concepts
requires requires { { __x.base() < __y.base() } -> convertible_to<bool>; }
#endif
{ return !(__x < __y); }
@@ -1725,7 +1729,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const move_iterator<_Iterator>& __y)
{ return __x.base() == __y.base(); }
-#if __cpp_lib_three_way_comparison
+#ifdef __cpp_lib_three_way_comparison
template<three_way_comparable _Iterator>
[[__nodiscard__]]
constexpr compare_three_way_result_t<_Iterator>
@@ -1825,7 +1829,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#define _GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(_Iter) (_Iter)
#endif // C++11
-#if __cplusplus > 201703L && __glibcxx_concepts
+#ifdef __glibcxx_ranges
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3736. move_iterator missing disable_sized_sentinel_for specialization
template<typename _Iterator1, typename _Iterator2>
@@ -1836,6 +1840,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// [iterators.common] Common iterators
+ /// @cond undocumented
namespace __detail
{
template<typename _It>
@@ -1850,6 +1855,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
&& constructible_from<iter_value_t<_It>, iter_reference_t<_It>>
&& move_constructible<iter_value_t<_It>>;
} // namespace __detail
+ /// @endcond
/// An iterator/sentinel adaptor for representing a non-common range.
template<input_or_output_iterator _It, sentinel_for<_It> _Sent>
@@ -2309,6 +2315,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// [iterators.counted] Counted iterators
+ /// @cond undocumented
namespace __detail
{
template<typename _It>
@@ -2337,6 +2344,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
struct __counted_iter_cat<_It>
{ using iterator_category = typename _It::iterator_category; };
}
+ /// @endcond
/// An iterator adaptor that keeps track of the distance to the end.
template<input_or_output_iterator _It>
@@ -2583,7 +2591,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void>;
};
-#if __glibcxx_ranges_as_const // >= C++23
+#ifdef __glibcxx_ranges_as_const // >= C++23
template<indirectly_readable _It>
using iter_const_reference_t
= common_reference_t<const iter_value_t<_It>&&, iter_reference_t<_It>>;
@@ -2956,8 +2964,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
make_const_sentinel(_Sent __s)
noexcept(is_nothrow_convertible_v<_Sent, const_sentinel<_Sent>>)
{ return __s; }
-#endif // C++23
-#endif // C++20
+#endif // C++23 ranges_as_const
+#endif // C++20 ranges
/// @} group iterators
@@ -3072,7 +3080,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// of associative containers.
template<typename _InputIterator>
using __iter_key_t = remove_const_t<
-#if __glibcxx_tuple_like // >= C++23
+#ifdef __glibcxx_tuple_like // >= C++23
tuple_element_t<0, typename
iterator_traits<_InputIterator>::value_type>>;
#else
typename iterator_traits<_InputIterator>::value_type::first_type>;
@@ -3080,7 +3088,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _InputIterator>
using __iter_val_t
-#if __glibcxx_tuple_like // >= C++23
+#ifdef __glibcxx_tuple_like // >= C++23
= tuple_element_t<1, typename
iterator_traits<_InputIterator>::value_type>;
#else
= typename iterator_traits<_InputIterator>::value_type::second_type;
--
2.47.0
