Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is an older version of Boost and was released in 2021. The current version is 1.89.0.

static_string::append (7 of 9 overloads)

static_string&
append(
    std::initializer_list< CharT > init);