ACCEPT(2)                            BSD                             ACCEPT(2)



NAME
     accept - accept a connection on a socket

SYNOPSIS
     #include <sys/types.h>
     #include <sys/socket.h>

     ns = accept(s, addr, addrlen)
     int ns, s;
     struct sockaddr *addr;
     int *addrlen;

DESCRIPTION
     The argument s is a socket that has been created with socket(2), bound to
     an address with bind(2), and is listening for connections after a
     listen(2).  accept extracts the first connection on the queue of pending
     connections, creates a new socket with the same properties of s, and
     allocates a new file descriptor (ns) for the socket.  If no pending
     connections are present on the queue, and the socket is not marked as
     non-blocking, accept blocks the caller until a connection is present.  If
     the socket is marked non-blocking and no pending connections are present
     on the queue, accept returns an error as described below.  The accepted
     socket, ns, can not be used to accept more connections.  The original
     socket s remains open.

     The argument addr is a result parameter that is filled in with the
     address of the connecting entity, as known to the communications layer.
     The exact format of the addr parameter is determined by the domain in
     which the communication is occurring.  The addrlen is a value-result
     parameter; it should initially contain the amount of space pointed to by
     addr; on return it will contain the actual length (in bytes) of the
     address returned.  This call is used with connection-based socket types,
     currently with SOCK_STREAM.

     It is possible to select(2) a socket for the purposes of doing an accept
     by selecting it for read.

ERRORS
     The accept will fail if any of the following are true:

     [EBADF]         The descriptor is invalid.

     [ENOTSOCK]      The descriptor references a file, not a socket.

     [EOPNOTSUPP]    The referenced socket is not of type SOCK_STREAM.

     [EFAULT]        The addr parameter is not in a writable part of the user
                     address space.

     [EWOULDBLOCK]   The socket is marked non-blocking and no connections are
                     present to be accepted.

SEE ALSO
     bind(2), connect(2), listen(2), select(2), socket(2)

DIAGNOSTICS
     The call returns -1 on error.  If it succeeds, it returns a non-negative
     integer that is a descriptor for the accepted socket.