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 2018. The current version is 1.91.0.

buffers_adapter::max_size

Returns the largest size output sequence possible.

std::size_t
max_size() const;