std::basic_string<CharT,Traits,Allocator>::operator basic_string_view
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< cpp | string | basic string
C++
Strings library
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std::basic_string
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| operator std::basic_string_view<CharT, Traits>() const noexcept; |
(since C++17) (constexpr since C++20) |
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Returns a std::basic_string_view, constructed as if by std::basic_string_view<CharT, Traits>(data(), size().
Contents |
[edit] Parameters
(none)
[edit] Return value
A string view representing the entire contents of the string.
[edit] 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
[edit] Example
Run this code
#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); }
Output:
ラーメン 12 code units 4 code points
[edit] See also
constructs a basic_string_view (public member function of std::basic_string_view<CharT,Traits>) [edit]
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