std::basic_string_view::data

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Strings library

Null-terminated strings

Byte strings

Multibyte strings

Wide strings

Classes

basic_string

basic_string_view (C++17)

char_traits

 

std::basic_string_view

Member functions basic_string_view::basic_string_view basic_string_view::operator= Iterators basic_string_view::beginbasic_string_view::cbegin basic_string_view::endbasic_string_view::cend basic_string_view::rbeginbasic_string_view::crbegin basic_string_view::rendbasic_string_view::crend Element access basic_string_view::at basic_string_view::operator[] basic_string_view::front basic_string_view::back basic_string_view::data Capacity basic_string_view::sizebasic_string_view::length basic_string_view::max_size basic_string_view::empty Modifers basic_string_view::remove_prefix basic_string_view::remove_suffix basic_string_view::swap

Operations basic_string_view::copy basic_string_view::substr basic_string_view::compare basic_string_view::find basic_string_view::rfind basic_string_view::find_first_of basic_string_view::find_last_of basic_string_view::find_first_not_of basic_string_view::find_last_not_of Constants basic_string_view::npos Non-member functions operator==operator!=operator<operator>operator<=operator>= operator<< operator""sv Helper classes hash<std::string_view>hash<std::wstring_view>hash<std::u16string_view>hash<std::u32string_view>

 

constexpr const_pointer data() const;		(since C++17)

Returns a pointer to the underlying character array. The pointer is such that the range [data(); data() + size()) is valid and the values in it correspond to the values of the view.

Parameters

(none)

Return value

A pointer to the underlying character array.

Exceptions

noexcept specification:  

noexcept

  

Complexity

Constant.

Notes

Unlike std::basic_string::data() and string literals, data() may return a pointer to a buffer that is not null-terminated. Therefore it is typically a mistake to pass data() to a routine that takes just a const CharT* and expects a null-terminated string.

Example

Run this code

#include <iostream>
#include <cstring>
#include <cwchar>
#include <string>
#include <string_view>
int main()
{
    std::wstring_view wcstr_v = L"xyzzy";
    std::cout << std::wcslen(wcstr_v.data()) << '\n';
    // OK: the underlying character array is null-terminated
 
    char array[3] = {'B', 'a', 'r'};
    std::string_view array_v(array, sizeof array);
    // std::cout << std::strlen(array_v.data()) << '\n';
    // error: the underlying character array is not null-terminated
 
    std::string str(array_v.data(), array_v.size()); // OK
    std::cout << std::strlen(str.data()) << '\n';
    // OK: the underlying character array of a std::string is always null-terminated
}

Output:

5
3

See also

front	accesses the first character (public member function)
back	accesses the last character (public member function)