ACCEPT(3XNET) X/Open Networking Services Library Functions ACCEPT(3XNET)

NAME

accept - accept a new connection on a socket

SYNOPSIS

cc [ flag ... ] file ... -lxnet [ library ... ]
#include <sys/socket.h>


int accept(int socket, struct sockaddr *restrict address,
socklen_t *restrict address_len);

DESCRIPTION

The accept() function extracts the first connection on the queue of
pending connections, creates a new socket with the same socket type
protocol and address family as the specified socket, and allocates a
new file descriptor for that socket.


The function takes the following arguments:

socket
Specifies a socket that was created with
socket(3XNET), has been bound to an address with
bind(3XNET), and has issued a successful call to
listen(3XNET).


address
Either a null pointer, or a pointer to a sockaddr
structure where the address of the connecting socket
will be returned.


address_len
Points to a socklen_t which on input specifies the
length of the supplied sockaddr structure, and on
output specifies the length of the stored address.


If address is not a null pointer, the address of the peer for the
accepted connection is stored in the sockaddr structure pointed to by
address, and the length of this address is stored in the object
pointed to by address_len.


If the actual length of the address is greater than the length of the
supplied sockaddr structure, the stored address will be truncated.


If the protocol permits connections by unbound clients, and the peer
is not bound, then the value stored in the object pointed to by
address is unspecified.


If the listen queue is empty of connection requests and O_NONBLOCK is
not set on the file descriptor for the socket, accept() will block
until a connection is present. If the listen(3XNET) queue is empty of
connection requests and O_NONBLOCK is set on the file descriptor for
the socket, accept() will fail and set errno to EAGAIN or
EWOULDBLOCK.


The accepted socket cannot itself accept more connections. The
original socket remains open and can accept more connections.

USAGE

When a connection is available, select(3C) will indicate that the
file descriptor for the socket is ready for reading.

RETURN VALUES

Upon successful completion, accept() returns the nonnegative file
descriptor of the accepted socket. Otherwise, -1 is returned and
errno is set to indicate the error.

ERRORS

The accept() function will fail if:

EAGAIN
EWOULDBLOCK
O_NONBLOCK is set for the socket file descriptor and
no connections are present to be accepted.


EBADF
The socket argument is not a valid file descriptor.


ECONNABORTED
A connection has been aborted.


EFAULT
The address or address_len parameter can not be
accessed or written.


EINTR
The accept() function was interrupted by a signal
that was caught before a valid connection arrived.


EINVAL
The socket is not accepting connections.


EMFILE
OPEN_MAX file descriptors are currently open in the
calling process.


ENFILE
The maximum number of file descriptors in the system
are already open.


ENOTSOCK
The socket argument does not refer to a socket.


EOPNOTSUPP
The socket type of the specified socket does not
support accepting connections.


The accept() function may fail if:

ENOBUFS
No buffer space is available.


ENOMEM
There was insufficient memory available to complete the
operation.


ENOSR
There was insufficient STREAMS resources available to
complete the operation.


EPROTO
A protocol error has occurred; for example, the STREAMS
protocol stack has not been initialized.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO

sockaddr(3SOCKET), bind(3XNET), connect(3XNET), listen(3XNET),
socket(3XNET), attributes(7), standards(7)

November 1, 2003 ACCEPT(3XNET)