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SHUTDOWN(2) System Calls Manual SHUTDOWN(2)

NAME

shutdowndisable sends or receives on a socket

SYNOPSIS

#include <sys/socket.h>
int
shutdown(int s, int how);

DESCRIPTION

The shutdown() system call disables sends or receives on a socket.
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 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.
 
 
SHUT_RDWR
Further sends and receives will be disallowed.
The following protocol specific actions apply to the use of SHUT_WR based on the properties of the socket associated with the file descriptor s:
DOMAIN TYPE PROTOCOL RETURN VALUE AND ACTION
AF_INET SOCK_DGRAM IPPROTO_UDP Return 0. ICMP messages will not be generated.
AF_INET SOCK_STREAM IPPROTO_TCP Return 0. Send queued data, wait for ACK, then send FIN.
AF_INET6 SOCK_DGRAM IPPROTO_UDP Return 0. ICMP messages will not be generated.
AF_INET6 SOCK_STREAM IPPROTO_TCP Return 0. Send queued data, wait for ACK, then send FIN.

RETURN VALUES

Upon successful completion, the value 0 is returned; 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 SOCK_STREAM socket which is not connected.
 
 
[ENOTSOCK]
The s argument does not refer to a socket.
 
 
[EOPNOTSUPP]
The socket associated with the file descriptor s does not support this operation.

SEE ALSO

connect(2), socket(2), inet(4), inet6(4)

STANDARDS

The shutdown() function conforms to IEEE Std 1003.1-2008 (“POSIX.1”).

HISTORY

The shutdown() system call first appeared in 4.1cBSD. The SHUT_RD, SHUT_WR, and SHUT_RDWR constants appeared in IEEE Std 1003.1g-2000 (“POSIX.1g”).

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.
September 9, 2014 OpenBSD-current