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std::basic_...string_view(3)   C++ Standard Libary  std::basic_...string_view(3)

NAME
     std::basic_string::operatorbasic_string_view - std::basic_string::operator-
     basic_string_view

Synopsis
	operator   std::basic_string_view<CharT,  Traits>()  const	  (since
     C++17)
	noexcept;						      (constexpr
     since C++20)

	Returns   a   std::basic_string_view,  constructed  as	if  by	std::ba-
     sic_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
     // 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 = "a(C)a1/4a!a^3";   // narrow string
	  std::wstring wcstr = L"a(C)a1/4a!a^3";  // 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:
      a(C)a1/4a!a^3
      12 code units
      4 code points

See also
		      constructs a basic_string_view
	constructor	   (public	member	    function	 of	std::ba-
     sic_string_view<CharT,Traits>)

http://cppreference.com 	   2024.06.10	    std::basic_...string_view(3)
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