...one of the most highly
regarded and expertly designed C++ library projects in the
world. — Herb Sutter and Andrei
Determine the number of bytes available for reading.
std::size_t available( boost::system::error_code & ec) const;
This function is used to determine the number of bytes that may be read without blocking.
Set to indicate what error occurred, if any.
The number of bytes that may be read without blocking, or 0 if an error occurs.