std::basic_string_view<CharT,Traits>::data
< cpp | string | basic string view
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, 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
accesses the first character (public member function) | |
accesses the last character (public member function) |