ISO/IEC TS 19216:2018 describes extensions to the C++ Standard Library. This document specifies requirements for implementations of an interface that computer programs written in the C++ programming language may use to perform operations related to networking, such as operations involving sockets, timers, buer management, host name resolution and internet protocols. This document is applicable to information technology systems that can perform network operations, such as those with operating systems that conform to the POSIX interface. This document is applicable only to vendors who wish to provide the interface it describes.