.TH accept 3 "MiNT-Net"

.SH NAME

accept \- accept a connection on a socket

.SH SYNOPSIS

.B #include <sys/socket.h>

.SS \s-1AF_UNIX\s0 only:

.B #include <sys/un.h>

.PP

.B "int accept(int s, struct sockaddr \(**addr, size_t \(**addrlen);"

.SH DESCRIPTION

This call is used with connection-based socket types, such as

.SM SOCK_STREAM.

The argument

.I s

is a socket descriptor created with

.IR socket (3),

bound to an address with

.IR bind (3),

and listening for connections after a

.IR listen (3).

.I accept

extracts the first connection on the queue of pending connections,

creates a new socket with the same properties as

.IR s ,

and allocates a new file descriptor,

.IR ns ,

for the socket.

If no pending connections are present on the queue

and non-blocking mode has not been enabled using the

.SM O_NDELAY

.I fcntl

flag,

.I accept

blocks the caller until a connection is present.

.SM O_NDELAY

is defined in

.RB < fcntl.h >\s0.

If the socket is marked non-blocking and no pending

connections are present on the queue,

.I accept

returns an error as described below.

The accepted socket,

.IR ns ,

cannot be used to accept more connections.

The original socket

.I s

remains open.

It is possible to determine if a listening socket

has pending connection requests ready for an

.I accept

call by using

.IR select (3)

for reading.

.PP

The argument

.I addr

should point to a local socket address structure.

The

.I accept

call fills in this structure with the address of the connecting entity,

as known to the underlying protocol.

The format of the address depends upon the protocol

and the address-family of the socket

.IR s .

The

.I addrlen

is a pointer to an argument of type size_t;

it should initially contain the size

of the structure pointed to by

.IR addr .

On return, it contains the actual length (in bytes)

of the address returned.

If the memory pointed to by

.I addr

is not large enough to contain the entire address, only the first

.I addrlen

bytes of the address are returned.

.SH RETURN VALUE

The call returns \-1 on error.

If successful, it returns a non-negative integer

which is a descriptor for the accepted socket.

.SH DIAGNOSTICS

.I accept

fails if:

.TP 25

.SM [EBADF]

The file descriptor

.I s

is invalid.

.TP

.SM [EOPNOTSUPP]

The socket referenced by

.I s

is not of type

.SM SOCK_STREAM.

.TP

.SM [EWOULDBLOCK]

Non-blocking

.SM I/O

is enabled using

.SM O_NDELAY

and no connections are present to be accepted.

.TP

.SM [EMFILE]

The maximum number of file descriptors for this process

are already currently open.

.TP

.SM [ENOMEM]

No buffer space is available.

The

.I accept

cannot complete.

The queued socket connect request is aborted.

.TP

.SM [ECONNABORTED]

The socket referenced by

.I s

has been

.IR shutdown

for reading.

.TP

.SM [EINVAL]

The socket referenced by

.I s

is not currently a listening socket or has been fully

.IR shutdown .

A

.I listen

must be done before an

.I accept

is allowed.

The file descriptor

.I s

references a file, not a socket.

.TP

.SM [EINTR]

The call was interrupted by a signal before a valid connection arrived.

.SH SEE ALSO

bind(3),

connect(3),

listen(3),

select(3),

socket(3).