SOCKET(3XNET)SOCKET(3XNET)NAMEsocket - create an endpoint for communication
SYNOPSIS
cc [ flag ... ] file ... -lxnet [ library ... ]
#include <sys/socket.h>
int socket(int domain, int type, int protocol);
DESCRIPTION
The socket() function creates an unbound socket in a communications
domain, and returns a file descriptor that can be used in later func‐
tion calls that operate on sockets.
The <sys/socket.h> header defines at least the following values for the
domain argument:
AF_UNIX
File system pathnames.
AF_INET
Internet Protocol version 4 (IPv4) address.
AF_INET6
Internet Protocol version 6 (IPv6) address.
The type argument specifies the socket type, which determines the
semantics of communication over the socket. The socket types supported
by the system are implementation-dependent. Possible socket types
include:
SOCK_STREAM
Provides sequenced, reliable, bidirectional, connec‐
tion-mode byte streams, and may provide a transmis‐
sion mechanism for out-of-band data.
SOCK_DGRAM
Provides datagrams, which are connectionless-mode,
unreliable messages of fixed maximum length.
SOCK_SEQPACKET
Provides sequenced, reliable, bidirectional, connec‐
tion-mode transmission path for records. A record
can be sent using one or more output operations and
received using one or more input operations, but a
single operation never transfers part of more than
one record. Record boundaries are visible to the
receiver via the MSG_EOR flag.
If the protocol argument is non-zero, it must specify a protocol that
is supported by the address family. The protocols supported by the
system are implementation-dependent.
The process may need to have appropriate privileges to use the socket()
function or to create some sockets.
PARAMETERS
The function takes the following arguments:
domain
Specifies the communications domain in which a socket is to
be created.
type
Specifies the type of socket to be created.
protocol
Specifies a particular protocol to be used with the socket.
Specifying a protocol of 0 causes socket() to use an
unspecified default protocol appropriate for the requested
socket type.
The domain argument specifies the address family used in the communica‐
tions domain. The address families supported by the system are imple‐
mentation-dependent.
USAGE
The documentation for specific address families specify which protocols
each address family supports. The documentation for specific protocols
specify which socket types each protocol supports.
The application can determine if an address family is supported by try‐
ing to create a socket with domain set to the protocol in question.
RETURN VALUES
Upon successful completion, socket() returns a nonnegative integer, the
socket file descriptor. Otherwise a value of -1 is returned and errno
is set to indicate the error.
ERRORS
The socket() function will fail if:
EAFNOSUPPORT
The implementation does not support the specified
address family.
EMFILE
No more file descriptors are available for this
process.
ENFILE
No more file descriptors are available for the sys‐
tem.
EPROTONOSUPPORT
The protocol is not supported by the address family,
or the protocol is not supported by the implementa‐
tion.
EPROTOTYPE
The socket type is not supported by the protocol.
The socket() function may fail if:
EACCES
The process does not have appropriate privileges.
ENOBUFS
Insufficient resources were available in the system to per‐
form the operation.
ENOMEM
Insufficient memory was available to fulfill the request.
ENOSR
There were insufficient STREAMS resources available for the
operation to complete.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Standard │
├────────────────────┼─────────────────┤
│MT-Level │ MT-Safe │
└────────────────────┴─────────────────┘
SEE ALSOaccept(3XNET), bind(3XNET), connect(3XNET), getsockname(3XNET), get‐
sockopt(3XNET), listen(3XNET), recv(3XNET), recvfrom(3XNET),
recvmsg(3XNET), send(3XNET), sendmsg(3XNET), setsockopt(3XNET), shut‐
down(3XNET), socketpair(3XNET), attributes(5), standards(5)
Jun 10, 2002 SOCKET(3XNET)
