accept(3SOCKET) Sockets Library Functions accept(3SOCKET)NAMEaccept - accept a connection on a socket
SYNOPSIS
cc [ flag ... ] file ... -lsocket-lnsl [ library ... ]
#include <sys/types.h>
#include <sys/socket.h>
int accept(int s, struct sockaddr *addr, socklen_t *addrlen);
DESCRIPTION
The argument s is a socket that has been created with socket(3SOCKET)
and bound to an address with bind(3SOCKET), and that is listening for
connections after a call to listen(3SOCKET). The accept() function
extracts the first connection on the queue of pending connections, cre‐
ates a new socket with the properties of s, and allocates a new file
descriptor, ns, for the socket. If no pending connections are present
on the queue and the socket is not marked as non-blocking, accept()
blocks the caller until a connection is present. If the socket is
marked as non-blocking and no pending connections are present on the
queue, accept() returns an error as described below. The accept()
function uses the netconfig(4) file to determine the STREAMS device
file name associated with s. This is the device on which the connect
indication will be accepted. The accepted socket, ns, is used to read
and write data to and from the socket that connected to ns. It is not
used to accept more connections. The original socket (s) remains open
for accepting further connections.
The argument addr is a result parameter that is filled in with the
address of the connecting entity as it is known to the communications
layer. The exact format of the addr parameter is determined by the
domain in which the communication occurs.
The argument addrlen is a value-result parameter. Initially, it con‐
tains the amount of space pointed to by addr; on return it contains the
length in bytes of the address returned.
The accept() function is used with connection-based socket types, cur‐
rently with SOCK_STREAM.
It is possible to select(3C) or poll(2) a socket for the purpose of an
accept() by selecting or polling it for a read. However, this will only
indicate when a connect indication is pending; it is still necessary to
call accept().
RETURN VALUES
The accept() function returns −1 on error. If it succeeds, it returns a
non-negative integer that is a descriptor for the accepted socket.
ERRORSaccept() will fail if:
EBADF The descriptor is invalid.
ECONNABORTED The remote side aborted the connection before the
accept() operation completed.
EFAULT The addr parameter or the addrlen parameter is invalid.
EINTR The accept() attempt was interrupted by the delivery of
a signal.
EMFILE The per-process descriptor table is full.
ENODEV The protocol family and type corresponding to s could
not be found in the netconfig file.
ENOMEM There was insufficient user memory available to com‐
plete the operation.
ENOSR There were insufficient STREAMS resources available to
complete the operation.
ENOTSOCK The descriptor does not reference a socket.
EOPNOTSUPP The referenced socket is not of type SOCK_STREAM.
EPROTO A protocol error has occurred; for example, the STREAMS
protocol stack has not been initialized or the connec‐
tion has already been released.
EWOULDBLOCK The socket is marked as non-blocking and no connections
are present to be accepted.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOpoll(2), bind(3SOCKET), connect(3SOCKET), listen(3SOCKET), select(3C),
socket.h(3HEAD), socket(3SOCKET), netconfig(4), attributes(5)SunOS 5.11 24 Jan 2002 accept(3SOCKET)
