EN JA
SHUTDOWN(2)
SHUTDOWN(2) FreeBSD System Calls Manual SHUTDOWN(2)

NAME

shutdowndisable sends and/or receives on a socket

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

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

int
shutdown( int s, int how);

DESCRIPTION

The shutdown() system call disables sends or receives on a socket. The how argument specifies the type of shutdown. Possible values are:
SHUT_RD
Further receives will be disallowed.
SHUT_WR
Further sends will be disallowed. This may cause actions specific to the protocol family of the socket s to happen; see IMPLEMENTATION NOTES.
SHUT_RDWR
Further sends and receives will be disallowed. Implies SHUT_WR.

If the file descriptor s is associated with a SOCK_STREAM socket, all or part of the full-duplex connection will be shut down.

IMPLEMENTATION NOTES

The following protocol specific actions apply to the use of SHUT_WR (and potentially also SHUT_RDWR), based on the properties of the socket associated with the file descriptor s.
Domain Type Protocol Return value and action
PF_INET SOCK_DGRAM IPPROTO_SCTP Return -1. The global variable errno will be set to EOPNOTSUPP.
PF_INET SOCK_DGRAM IPPROTO_UDP Return 0. ICMP messages will not be generated.
PF_INET SOCK_STREAM IPPROTO_SCTP Return 0. Send queued data and tear down association.
PF_INET SOCK_STREAM IPPROTO_TCP Return 0. Send queued data, wait for ACK, then send FIN.
PF_INET6 SOCK_DGRAM IPPROTO_SCTP Return -1. The global variable errno will be set to EOPNOTSUPP.
PF_INET6 SOCK_DGRAM IPPROTO_UDP Return 0. ICMP messages will not be generated.
PF_INET6 SOCK_STREAM IPPROTO_SCTP Return 0. Send queued data and tear down association.
PF_INET6 SOCK_STREAM IPPROTO_TCP Return 0. Send queued data, wait for ACK, then send FIN.

RETURN VALUES

The shutdown() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

ERRORS

The shutdown() system call fails if:
[ EBADF]
The s argument is not a valid file descriptor.
[ EINVAL]
The how argument is invalid.
[ EOPNOTSUPP]
The socket associated with the file descriptor s does not support this operation.
[ ENOTCONN]
The s argument specifies a SOCK_STREAM socket which is not connected.
[ ENOTSOCK]
The s argument does not refer to a socket.

STANDARDS

The shutdown() system call is expected to comply with IEEE Std 1003.1g-2000 (“POSIX.1g”), when finalized.

HISTORY

The shutdown() system call appeared in 4.2BSD. The SHUT_RD, SHUT_WR, and SHUT_RDWR constants appeared in IEEE Std 1003.1g-2000 (“POSIX.1g”).

AUTHORS

This manual page was updated by Bruce M. Simpson <bms@FreeBSD.org> to reflect how shutdown() behaves with PF_INET and PF_INET6 sockets.

BUGS

The ICMP “ port unreachable” message should be generated in response to datagrams received on a local port to which s is bound after shutdown() is called.
March 5, 2007 FreeBSD