accept(3N) NETWORK FUNCTIONS accept(3N)
NAME
accept - accept a connection on a socket
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
ns = accept(s, addr, addrlen)
int ns, s;
struct sockaddr *addr;
int *addrlen;
DESCRIPTION
The argument s is a socket that has been created with
socket(3N) and bound to an address with bind(3N), and that
is listening for connections after a call to listen(3N).
accept() extracts the first connection on the queue of pend-
ing connections, creates 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. accept() uses the netconfig(4) file to determine the
STREAMS device file name associated with s. This is the dev-
ice 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 communi-
cation occurs. addrlen is a value-result parameter. Ini-
tially, it contains the amount of space pointed to by addr;
on return it contains the length in bytes of the address
returned. accept() is used with connection-based socket
types, currently with SOCKSTREAM.
It is possible to select(3N) a socket for the purpose of an
accept() by selecting it for read. However, this will only
indicate when a connect indication is pending; it is still
necessary to call accept().
RETURN VALUE
accept() returns -1 on error. If it succeeds, it returns a
non-negative integer that is a descriptor for the accepted
socket.
Last change: 1
accept(3N) NETWORK FUNCTIONS accept(3N)
ERRORS
accept() will fail if:
EBADF The descriptor is invalid.
ENOTSOCK The descriptor does not reference a
socket.
EOPNOTSUPP The referenced socket is not of type
SOCKSTREAM.
EWOULDBLOCK The socket is marked as non-blocking and
no connections are present to be
accepted.
EPROTO A protocol error has occurred; for exam-
ple, the STREAMS protocol stack has not
been initialized.
ENODEV The protocol family and type correspond-
ing to s could not be found in the
netconfig file.
ENOMEM There was insufficient user memory
available to complete the operation.
ENOSR There were insufficient STREAMS
resources available to complete the
operation.
SEE ALSO
bind(3N), connect(3N), listen(3N), socket(3N), netconfig(4).
Last change: 2