The SOCKETS interface is one of the interfaces for network programming within the POSIX subsystem. It can be used to develop communication applications based on the TCP/IP protocols. NEA and OSI protocols are not supported.
The SOCKETS interface is defined in a separate library. If this library is linked into a POSIX application, the SOCKETS interfaces set up the connection to the network over the POSIX subsystem and BCAM transport system.
The POSIX network connection libraries represent the link between the POSIX objects, such as file descriptors, and the BS2000 mechanisms. There are a few restrictions when using the functions because of the differences between the POSIX concepts and BS2000. These restrictions are described in detail in "Compatibility restrictions".
The functions for opening a network connection return a socket file descriptor. This can be used in all relevant POSIX functions which work with file descriptors.