BSDSockets

BSDSockets, also known as Berkeley sockets, is a programming interface for network communication that was originally developed in the Berkeley Software Distribution (BSD) of the Unix operating system. It provides a standardized way for applications to send and receive data across a network. The socket API allows programs to create endpoints for communication, connect to other endpoints, and transfer data.

The core concept of BSD sockets revolves around the socket descriptor, which is an integer handle representing an open connection or communication endpoint. When an application wants to communicate, it creates a socket. This socket can then be configured for different communication protocols, such as TCP (Transmission Control Protocol) for reliable, ordered data transfer, or UDP (User Datagram Protocol) for faster, connectionless communication.

Key operations in the BSD sockets API include socket creation, binding a socket to a specific address and port, listening for incoming connections, accepting connections, connecting to a remote host, sending data, and receiving data. Error handling is an integral part of the API, with functions returning specific error codes to indicate issues. While originating in BSD Unix, the BSD socket API has been widely adopted and implemented in many other operating systems, including Linux, macOS, and Windows, forming the foundation for much of the internet's communication.