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shutdown
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Disable sends and/or receives on a socket.

#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 include:

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.

Remarks

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 Returns -1. The global variable errno will be set to EOPNOTSUPP.
IPPROTO_UDP Returns 0. ICMP messages will not be generated.
SOCK_STREAM IPPROTO_SCTP Returns 0. Send queued data and tear down association.
IPPROTO_TCP Returns 0. Send queued data, wait for ACK, then send FIN.
PF_INET6 SOCK_DGRAM IPPROTO_SCTP Returns -1. The global variable errno will be set to EOPNOTSUPP.
IPPROTO_UDP Returns 0. ICMP messages will not be generated.
SOCK_STREAM IPPROTO_SCTP Returns 0. Send queued data and tear down association.
IPPROTO_TCP Returns 0. Send queued data, wait for ACK, then send FIN.

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.

Return Values

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

Requirements

Versions Link to
INtime 4.0 netlib.lib

See Also

connect, socket, inet, inet64

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