SHUTDOWN(2) BSD System Calls Manual SHUTDOWN(2)
shutdown -- disable sends and/or receives on a socket
Standard C Library (libc, -lc)
shutdown(int s, int how);
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
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.
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.
The shutdown() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indi-
cate the error.
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.
connect(2), socket(2), inet(4), inet6(4)
The shutdown() system call is expected to comply with IEEE Std 1003.1g-2000 (``POSIX.1''), when finalized.
The shutdown() system call appeared in 4.2BSD. The SHUT_RD, SHUT_WR, and SHUT_RDWR constants appeared in IEEE Std 1003.1g-2000
This manual page was updated by Bruce M. Simpson <bms@FreeBSD.org> to reflect how shutdown() behaves with PF_INET and PF_INET6 sockets.
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 BSD