std::basic_string_view<CharT,Traits>::data - cppreference.com (original) (raw)

| 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.

[edit] Parameters

(none)

[edit] Return value

A pointer to the underlying character array.

[edit] Complexity

Constant.

[edit] 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.

[edit] Example

#include #include #include #include #include   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:

[edit] See also

| | accesses the first character (public member function) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | | accesses the last character (public member function) [edit] | | | returns a pointer to the first character of a string (public member function of std::basic_string<CharT,Traits,Allocator>) [edit] |