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.Dd July 27, 2015 .Dt SHUTDOWN 2 .Os .Sh NAME .Nm shutdown .Nd disable sends and/or receives on a socket .Sh LIBRARY .Lb libc .Sh SYNOPSIS n sys/types.h n sys/socket.h .Ft int .Fn shutdown "int s" "int how" .Sh DESCRIPTION The .Fn shutdown system call disables sends or receives on a socket. The .Fa how argument specifies the type of shutdown. Possible values are: l -tag -width ".Dv SHUT_RDWR" t Dv SHUT_RD Further receives will be disallowed. t Dv SHUT_WR Further sends will be disallowed. This may cause actions specific to the protocol family of the socket .Fa s to happen; see .Sx IMPLEMENTATION NOTES . t Dv SHUT_RDWR Further sends and receives will be disallowed. Implies .Dv SHUT_WR . .El
p
If the file descriptor
.Fa s
is associated with a
.Dv SOCK_STREAM
socket, all or part of the full-duplex connection will be shut down.
.Sh IMPLEMENTATION NOTES
The following protocol specific actions apply to the use of
.Dv SHUT_WR
(and potentially also
.Dv SHUT_RDWR ) ,
based on the properties of the socket associated with the file descriptor
.Fa s .
l -column ".Dv PF_INET6" ".Dv SOCK_STREAM" ".Dv IPPROTO_SCTP" t Sy Domain Ta Sy Type Ta Sy Protocol Ta Sy Action t Dv PF_INET Ta Dv SOCK_DGRAM Ta Dv IPPROTO_SCTP Ta Failure,
as socket is not connected.
t Dv PF_INET Ta Dv SOCK_DGRAM Ta Dv IPPROTO_UDP Ta Failure,
as socket is not connected.
t Dv PF_INET Ta Dv SOCK_STREAM Ta Dv IPPROTO_SCTP Ta Send queued data and tear down association.
t Dv PF_INET Ta Dv SOCK_STREAM Ta Dv IPPROTO_TCP Ta Send queued data, wait for ACK, then send FIN.
t Dv PF_INET6 Ta Dv SOCK_DGRAM Ta Dv IPPROTO_SCTP Ta Failure,
as socket is not connected.
t Dv PF_INET6 Ta Dv SOCK_DGRAM Ta Dv IPPROTO_UDP Ta Failure,
as socket is not connected.
t Dv PF_INET6 Ta Dv SOCK_STREAM Ta Dv IPPROTO_SCTP Ta Send queued data and tear down association.
t Dv PF_INET6 Ta Dv SOCK_STREAM Ta Dv IPPROTO_TCP Ta Send queued data, wait for ACK, then send FIN.
.El
.Sh RETURN VALUES
.Rv -std shutdown
.Sh ERRORS
The
.Fn shutdown
system call fails if:
l -tag -width Er t Bq Er EBADF The
.Fa s
argument is not a valid file descriptor.
t Bq Er EINVAL The
.Fa how
argument is invalid.
t Bq Er ENOTCONN The
.Fa s
argument specifies a socket which is not connected.
t Bq Er ENOTSOCK The
.Fa s
argument does not refer to a socket.
.El
.Sh SEE ALSO
.Xr connect 2 ,
.Xr socket 2 ,
.Xr inet 4 ,
.Xr inet6 4
.Sh STANDARDS
The
.Fn shutdown
system call is expected to comply with
.St -p1003.1g-2000 ,
when finalized.
.Sh HISTORY
The
.Fn shutdown
system call appeared in
x 4.2 . The
.Dv SHUT_RD , SHUT_WR ,
and
.Dv SHUT_RDWR
constants appeared in
.St -p1003.1g-2000 .
.Sh AUTHORS
.An -nosplit
This manual page was updated by
.An Bruce M. Simpson Aq Mt bms@FreeBSD.org
to reflect how
.Fn shutdown
behaves with
.Dv PF_INET
and
.Dv PF_INET6
sockets.
.Sh BUGS
The ICMP
.Dq Li "port unreachable"
message should be generated in response to
datagrams received on a local port to which
.Fa s
is bound
after
.Fn shutdown
is called.