accept - accept a new connection on a socket
cc [ flag ... ] file ... -lxnet [ library ... ]
#include <sys/socket.h>
int accept(int socket, struct sockaddr *restrict address,
socklen_t *restrict address_len);
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
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.
When a connection is available, select(3C) will indicate that the file
descriptor for the socket is ready for reading.
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.
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.
See attributes(7) for descriptions of the following attributes:
| ATTRIBUTE
TYPE |
ATTRIBUTE VALUE |
| Interface Stability |
Standard |
| MT-Level |
MT-Safe |