std::ranges::views::istream, std::ranges::basic_istream_view, std::ranges::istream_view, std::ranges::wistream_view - cppreference.com (original) (raw)

std::ranges::basic_istream_view

1. A range factory that generates a sequence of elements by repeatedly calling operator>>.

2,3) Convenience alias templates for character types char and wchar_t.

1. views::istream<T>(e) is expression-equivalent to ranges::basic_istream_view<T, typename U::char_type, typename U::traits_type>(e) for any suitable subexpressions e, where U is std::remove_reference_t<decltype(e)>.

The program is ill-formed if U is not both publicly and unambiguously derived from std::basic_istream<typename U::char_type, typename U::traits_type>, which may result in a substitution failure.

1. The exposition-only concept /*stream-extractable*/<Val, CharT, Traits> is satisfied when lvalue of type Val can be extracted from lvalue of type std::basic_istream<CharT, Traits>.

The iterator type of basic_istream_view is move-only: it does not meet the LegacyIterator requirements, and thus does not work with pre-C++20 algorithms.

Contents

• 1 Customization point objects
• 2 Data members
• 3 Member functions
  • 3.1 Inherited from std::ranges::view_interface
• 4 std::ranges::basic_istream_view::basic_istream_view
• 5 std::ranges::basic_istream_view::begin
• 6 std::ranges::basic_istream_view::end
  • 6.1 Nested classes
  • 6.2 Example
  • 6.3 Defect reports
  • 6.4 See also

Customization point objects

The name views::istream<T> denotes a customization point object, which is a const function object of a literal semiregular class type. See CustomizationPointObject for details.

[edit] Data members

[edit] Member functions

std::ranges::basic_istream_view::basic_istream_view

| constexpr explicit basic_istream_view( std::basic_istream<CharT, Traits>& stream ); | | (since C++20) | | --------------------------------------------------------------------------------------------------------------------- | | ------------- |

Initializes _[stream](basic%5Fistream%5Fview.html#stream)_ with std::addressof(stream), and value-initializes _[value](basic%5Fistream%5Fview.html#value)_ .

std::ranges::basic_istream_view::begin

| constexpr auto begin(); | | (since C++20) | | ----------------------- | | ------------- |

Equivalent to *_[stream](basic%5Fistream%5Fview.html#stream)_ >> _[value](basic%5Fistream%5Fview.html#value)_ ; return iterator {*this};.

[edit] Nested classes

| | the iterator type of basic_istream_view(exposition-only member class*) | | ---------------------------------------------------------------------------- |

[edit] Example

Output:

/today/ /is/ /yesterday’s/ /tomorrow/ 1.1, 2.2, 3.3, 4.4, 55, 66, 7.7, 8.8,

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit] See also