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)