2004-11-03 13:51:07 +00:00
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.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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2007-06-20 22:33:04 +00:00
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.TH "ACCEPT" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.\" accept
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2007-09-20 06:03:25 +00:00
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.SH PROLOG
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This manual page is part of the POSIX Programmer's Manual.
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The Linux implementation of this interface may differ (consult
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the corresponding Linux manual page for details of Linux behavior),
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or the interface may not be implemented on Linux.
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2004-11-03 13:51:07 +00:00
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.SH NAME
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accept \- accept a new connection on a socket
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.SH SYNOPSIS
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.LP
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\fB#include <sys/socket.h>
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.br
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.sp
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int accept(int\fP \fIsocket\fP\fB, struct sockaddr *restrict\fP \fIaddress\fP\fB,
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.br
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\ \ \ \ \ \ socklen_t *restrict\fP \fIaddress_len\fP\fB);
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.br
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\fP
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.SH DESCRIPTION
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.LP
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The \fIaccept\fP() function shall extract the first connection on
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the queue of pending connections, create a new socket with
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the same socket type protocol and address family as the specified
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socket, and allocate a new file descriptor for that socket.
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.LP
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The \fIaccept\fP() function takes the following arguments:
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.TP 7
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\fIsocket\fP
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Specifies a socket that was created with \fIsocket\fP(), has been
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bound to an address
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with \fIbind\fP(), and has issued a successful call to \fIlisten\fP().
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.TP 7
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\fIaddress\fP
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Either a null pointer, or a pointer to a \fBsockaddr\fP structure
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where the address of the connecting socket shall be
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returned.
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.TP 7
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\fIaddress_len\fP
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Points to a \fBsocklen_t\fP structure which on input specifies the
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length of the supplied \fBsockaddr\fP structure, and on
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output specifies the length of the stored address.
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.sp
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.LP
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If \fIaddress\fP is not a null pointer, the address of the peer for
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the accepted connection shall be stored in the
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\fBsockaddr\fP structure pointed to by \fIaddress\fP, and the length
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of this address shall be stored in the object pointed to by
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\fIaddress_len\fP.
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.LP
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If the actual length of the address is greater than the length of
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the supplied \fBsockaddr\fP structure, the stored address
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shall be truncated.
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.LP
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If the protocol permits connections by unbound clients, and the peer
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is not bound, then the value stored in the object pointed
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to by \fIaddress\fP is unspecified.
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.LP
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If the listen queue is empty of connection requests and O_NONBLOCK
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is not set on the file descriptor for the socket,
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\fIaccept\fP() shall block until a connection is present. If the \fIlisten\fP()
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queue is
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empty of connection requests and O_NONBLOCK is set on the file descriptor
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for the socket, \fIaccept\fP() shall fail and set
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\fIerrno\fP to [EAGAIN] or [EWOULDBLOCK].
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.LP
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The accepted socket cannot itself accept more connections. The original
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socket remains open and can accept more connections.
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.SH RETURN VALUE
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.LP
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Upon successful completion, \fIaccept\fP() shall return the non-negative
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file descriptor of the accepted socket. Otherwise, -1
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shall be returned and \fIerrno\fP set to indicate the error.
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.SH ERRORS
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.LP
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The \fIaccept\fP() function shall fail if:
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.TP 7
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.B EAGAIN \fRor\fP EWOULDBLOCK
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.sp
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O_NONBLOCK is set for the socket file descriptor and no connections
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are present to be accepted.
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.TP 7
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.B EBADF
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The \fIsocket\fP argument is not a valid file descriptor.
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.TP 7
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.B ECONNABORTED
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.sp
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A connection has been aborted.
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.TP 7
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.B EINTR
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The \fIaccept\fP() function was interrupted by a signal that was caught
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before a valid connection arrived.
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.TP 7
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.B EINVAL
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The \fIsocket\fP is not accepting connections.
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.TP 7
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.B EMFILE
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{OPEN_MAX} file descriptors are currently open in the calling process.
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.TP 7
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.B ENFILE
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The maximum number of file descriptors in the system are already open.
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.TP 7
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.B ENOTSOCK
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The \fIsocket\fP argument does not refer to a socket.
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.TP 7
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.B EOPNOTSUPP
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The socket type of the specified socket does not support accepting
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connections.
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.sp
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.LP
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The \fIaccept\fP() function may fail if:
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.TP 7
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.B ENOBUFS
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No buffer space is available.
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.TP 7
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.B ENOMEM
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There was insufficient memory available to complete the operation.
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.TP 7
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.B EPROTO
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A protocol error has occurred; for example, the STREAMS protocol stack
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has not been initialized.
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.sp
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.LP
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None.
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.SH APPLICATION USAGE
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.LP
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When a connection is available, \fIselect\fP() indicates that the
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file descriptor for
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the socket is ready for reading.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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2007-09-20 06:11:55 +00:00
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\fIbind\fP(), \fIconnect\fP(), \fIlisten\fP()
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, \fIsocket\fP(), the Base Definitions volume of IEEE\ Std\ 1003.1-2001,
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2004-11-03 13:51:07 +00:00
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\fI<sys/socket.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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