W3cubDocs

/C++

std::basic_string_view

Defined in header <string_view>
template< 
    class CharT, 
    class Traits = std::char_traits<CharT> 
> class basic_string_view;
(since C++17)

The class template basic_string_view describes an object that can refer to a constant contiguous sequence of char-like objects with the first element of the sequence at position zero.

A typical implementation holds only two members: a pointer to constant CharT and a size.

Several typedefs for common character types are provided:

Defined in header <string_view>
Type Definition
std::string_view std::basic_string_view<char>
std::wstring_view std::basic_string_view<wchar_t>
std::u16string_view std::basic_string_view<char16_t>
std::u32string_view std::basic_string_view<char32_t>

Template parameters

CharT - character type
Traits - CharTraits class specifying the operations on the character type. Like for basic_string, Traits::char_type must name the same type as CharT or the behavior is undefined.

Member types

Member type Definition
traits_type Traits
value_type CharT
pointer CharT*
const_pointer const CharT*
reference CharT&
const_reference const CharT&
const_iterator implementation-defined constant RandomAccessIterator, ConstexprIterator (since C++20) and ContiguousIterator whose value_type is CharT
iterator const_iterator
reverse_iterator const_reverse_iterator
const_reverse_iterator std::reverse_iterator<const_iterator>
size_type std::size_t
difference_type std::ptrdiff_t

Note: iterator and const_iterator are the same type because string views are views into constant character sequences.

All requirements on the iterator types of a Container applies to the iterator and const_iterator types of basic_string_view as well.

Member functions

constructs a basic_string_view
(public member function)
assigns a view
(public member function)
Iterators
returns an iterator to the beginning
(public member function)
returns an iterator to the end
(public member function)
returns a reverse iterator to the beginning
(public member function)
returns a reverse iterator to the end
(public member function)
Element access
accesses the specified character
(public member function)
accesses the specified character with bounds checking
(public member function)
accesses the first character
(public member function)
accesses the last character
(public member function)
returns a pointer to the first character of a view
(public member function)
Capacity
returns the number of characters
(public member function)
returns the maximum number of characters
(public member function)
checks whether the view is empty
(public member function)
Modifiers
shrinks the view by moving its start forward
(public member function)
shrinks the view by moving its end backward
(public member function)
swaps the contents
(public member function)
Operations
copies characters
(public member function)
returns a substring
(public member function)
compares two views
(public member function)
(C++20)
checks if the string view starts with the given prefix
(public member function)
(C++20)
checks if the string view ends with the given suffix
(public member function)
find characters in the view
(public member function)
find the last occurrence of a substring
(public member function)
find first occurrence of characters
(public member function)
find last occurrence of characters
(public member function)
find first absence of characters
(public member function)
find last absence of characters
(public member function)

Constants

[static]
special value. The exact meaning depends on the context
(public static member constant)

Non-member functions

lexicographically compares two string views
(function template)
Input/output
performs stream output on string views
(function template)

Literals

Defined in inline namespace std::literals::string_view_literals
(C++17)
Creates a string view of a character array literal
(function)

Helper classes

(C++17)
hash support for string views
(class template specialization)

Notes

It is the programmer's responsibility to ensure that std::string_view does not outlive the pointed-to character array:

std::string_view good("a string literal");   // OK: "good" points to a static array
std::string_view bad("a temporary string"s); // "bad" holds a dangling pointer

© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
http://en.cppreference.com/w/cpp/string/basic_string_view