TCP/IP Socket Library Support for the CICS and Environment

Overview of the BSD UNIX Socket Library

BSD UNIX communications programming is based on the original UNIX framework, with some additions and elaborations to account for the greater complexity of interprocess communications. In traditional UNIX file I/O, an application issues an open call, which returns a file descriptor (a small integer) bound to a particular file or device. The application then issues a read or write call that causes the transfer of stream data. At the end of communications, the application issues a close call to terminate the interaction. Because interprocess communication often occurs over a network, the BSD UNIX socket library accounts for the numerous variables of network I/O, such as network protocols, and for the semantics of the UNIX file system.