Comtrol eCos - Manual (Page 575)

Chapter 38. TCP/IP Library Reference
BSD June 4, 1993 BSD
socket
SOCKET(2) System Calls Manual SOCKET(2)
NAME
socket - create an endpoint for communication
SYNOPSIS
#include < sys/types.h>
#include < sys/socket.h>
int
socket(int domain, int type, int protocol);
DESCRIPTION
socket() creates an endpoint for communication and returns a descriptor.
The domain parameter specifies a communications domain within which com-
munication will take place; this selects the protocol family which should
be used. These families are defined in the include file < sys/socket.h>.
The currently understood formats are
AF_UNIX (UNIX internal protocols),
AF_INET (ARPA Internet protocols),
AF_INET6 (ARPA IPv6 protocols),
AF_ISO (ISO protocols),
AF_NS (Xerox Network Systems protocols),
AF_IPX (Internetwork Packet Exchange), and
AF_IMPLINK (IMP host at IMP link layer).
The socket has the indicated type, which specifies the semantics of com-
munication. Currently defined types are:
SOCK_STREAM
SOCK_DGRAM
SOCK_RAW
SOCK_SEQPACKET
SOCK_RDM
A SOCK_STREAM type provides sequenced, reliable, two-way connection based
byte streams. An out-of-band data transmission mechanism may be sup-
ported. A SOCK_DGRAM socket supports datagrams (connectionless, unreli-
able messages of a fixed (typically small) maximum length). A
SOCK_SEQPACKET socket may provide a sequenced, reliable, two-way connec-
tion-based data transmission path for datagrams of fixed maximum length;
a consumer may be required to read an entire packet with each read system
call. This facility is protocol specific, and presently implemented only
for PF_NS. SOCK_RAW sockets provide access to internal network protocols
and interfaces. The types SOCK_RAW, which is available only to the supe-
ruser, and SOCK_RDM, which is planned, but not yet implemented, are not
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