Editing Berkeley sockets (section)

===socket===
The function ''socket()'' creates an endpoint for communication and returns a [[file descriptor]] for the socket. It uses three arguments:
* {{mono|<var>domain</var>}}, which specifies the protocol family of the created socket. For example:
**{{mono|PF_INET}} for network protocol [[IPv4]] (IPv4-only)
** {{mono|PF_INET6}} for [[IPv6]] (and in some cases, [[backward compatible]] with IPv4)
** {{mono|PF_UNIX}} for local socket (using a special filesystem node)
* {{mono|<var>type</var>}}, one of:
** {{mono|SOCK_STREAM}} (reliable stream-oriented service or [[stream socket]]s)
** {{mono|SOCK_DGRAM}} (datagram service or [[datagram socket]]s)
** {{mono|SOCK_SEQPACKET}} (reliable sequenced packet service)
** {{mono|SOCK_RAW}} (raw protocols atop the network layer)
* {{mono|<var>protocol</var>}} specifying the actual transport protocol to use. The most common are [[Transmission Control Protocol|{{mono|IPPROTO_TCP}}]], [[SCTP|{{mono|IPPROTO_SCTP}}]], [[User Datagram Protocol|{{mono|IPPROTO_UDP}}]], [[DCCP|{{mono|IPPROTO_DCCP}}]]. These protocols are specified in file ''netinet/in.h''. The value {{mono|0}} may be used to select a default protocol from the selected domain and type.

The function returns {{mono|-1}} if an error occurred. Otherwise, it returns an integer representing the newly assigned descriptor.