From cppreference.com
Defined in header <string_view>
template <class CharT, class Traits>

std::basic_ostream<CharT, Traits>&
    operator<<(std::basic_ostream<CharT, Traits>& os,

               std::basic_string_view <CharT, Traits> v);
(since C++17)

Behaves as a FormattedOutputFunction. After constructing and checking the sentry object, determines the output format padding as follows:

a) If v.size() is not less than os.width(), uses the range [v.begin(), v.end()) as-is
b) Otherwise, if (os.flags() & ios_base::adjustfield) == ios_base::left, places os.width()-v.size() copies of the os.fill() character after the character sequence
c) Otherwise, places os.width()-v.size() copies of the os.fill() character before the character sequence

Then stores each character from the resulting sequence (the contents of v plus padding) to the output stream os as if by calling os.rdbuf()->sputn(seq, n), where n=std::max(os.width(), str.size())

Finally, calls os.width(0) to cancel the effects of std::setw, if any.


May throw std::ios_base::failure if an exception is thrown during output.


os - a character output stream
v - the view to be inserted

Return value


See also

performs stream input and output on strings
(function template)