...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Defined in header <boost/static_string/static_string.hpp>
template< std::size_t N, std::size_t M, typename CharT, typename Traits> constexpr basic_static_string< N+M, CharT, Traits > operator+( const basic_static_string< N, CharT, Traits >& lhs, const basic_static_string< M, CharT, Traits >& rhs);