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 2013. The current version is 1.91.0.

buffered_stream::fill

buffered_stream::fill

Fill the buffer with some data. Returns the number of bytes placed in the buffer as a result of the operation. Throws an exception on failure.

std::size_t fill();

std::size_t fill(
    boost::system::error_code & ec);