NAME¶

std::basic_string_view::data - std::basic_string_view::data

Synopsis¶

constexpr const_pointer data() const noexcept; (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.

Complexity¶

Constant.

Notes¶

Unlike std::basic_string::data() and string literals, std::basic_string_view::data()
returns a pointer to a buffer that is not necessarily null-terminated, for example a
substring view (e.g. from remove_suffix). 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 <cstring>
#include <cwchar>
#include <iostream>
#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)
data returns a pointer to the first character of a string
(public member function of std::basic_string<CharT,Traits,Allocator>)