std::basic_string<CharT,Traits,Allocator>:: operator basic_string_view

Returns a std::basic_string_view , constructed as if by std:: basic_string_view < CharT, Traits > ( data ( ) , size ( ) ) .

Parameters

(none)

Return value

A string view representing the entire contents of the string.

Notes

It is the programmer's responsibility to ensure that the resulting string view does not outlive the string.

std::string get_string();
int f(std::string_view sv);
 
int x = f(get_string()); // OK
std::string_view sv = get_string(); // Bad: holds a dangling pointer

Example

#include <iostream>
#include <string>
#include <string_view>
 
void show_wstring_size(std::wstring_view wcstr_v)
{
    std::cout << wcstr_v.size() << " code points\n";
}
 
int main()
{
    std::string cppstr = "ラーメン";   // narrow string
    std::wstring wcstr = L"ラーメン";  // wide string
 
    // Implicit conversion from string to string_view
    // via std::string::operator string_view:
    std::string_view cppstr_v = cppstr;
 
    std::cout << cppstr_v << '\n'
              << cppstr_v.size() << " code units\n";
 
    // Implicit conversion from wstring to wstring_view
    // via std::wstring::operator wstring_view:
    show_wstring_size(wcstr);
}

ラーメン
12 code units
4 code points

See also