socket(3XNET) X/Open Networking Services Library Functions 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,
connection-mode byte streams, and may provide a
transmission 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,
connection-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 trans‐
fers 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 speci‐
fied address family.
EMFILE No more file descriptors are available for this
process.
ENFILE No more file descriptors are available for the
system.
EPROTONOSUPPORT The protocol is not supported by the address
family, or the protocol is not supported by the
implementation.
EPROTOTYPE The socket type is not supported by the proto‐
col.
The socket() function may fail if:
EACCES The process does not have appropriate privi‐
leges.
ENOBUFS Insufficient resources were available in the
system to perform 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)SunOS 5.10 10 Jun 2002 socket(3XNET)
