NAME
shutdown —
disable sends and/or receives on a
socket
LIBRARY
library “libc”
SYNOPSIS
#include
<sys/types.h>
#include <sys/socket.h>
int
shutdown(int
s, int how);
DESCRIPTION
Theshutdown()
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 | Action |
PF_INET |
SOCK_DGRAM |
IPPROTO_SCTP |
Failure, as socket is not connected. |
PF_INET |
SOCK_DGRAM |
IPPROTO_UDP |
Failure, as socket is not connected. |
PF_INET |
SOCK_STREAM |
IPPROTO_SCTP |
Send queued data and tear down association. |
PF_INET |
SOCK_STREAM |
IPPROTO_TCP |
Send queued data, wait for ACK, then send FIN. |
PF_INET6 |
SOCK_DGRAM |
IPPROTO_SCTP |
Failure, as socket is not connected. |
PF_INET6 |
SOCK_DGRAM |
IPPROTO_UDP |
Failure, as socket is not connected. |
PF_INET6 |
SOCK_STREAM |
IPPROTO_SCTP |
Send queued data and tear down association. |
PF_INET6 |
SOCK_STREAM |
IPPROTO_TCP |
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.
- [
ENOTCONN] - The s argument specifies a socket which is not connected.
- [
ENOTSOCK] - The s argument does not refer to a socket.
SEE ALSO
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.