man shutdown (2): disable sends and/or receives on a socket

LIBRARY

Lb libc

SYNOPSIS

In sys/types.h In sys/socket.h Ft int Fn shutdown int s int how

DESCRIPTION

The Fn shutdown system call disables sends or receives on a socket. The Fa 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 Fa s to happen; see Sx IMPLEMENTATION NOTES .
SHUT_RDWR: Further sends and receives will be disallowed. Implies SHUT_WR

If the file descriptor Fa 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 Fa s .

Domain Ta Type Ta Protocol Ta Return value and action
PF_INET Ta SOCK_DGRAM Ta IPPROTO_SCTP Ta Return -1.: The global variable errno will be set to Er EOPNOTSUPP .
PF_INET Ta SOCK_DGRAM Ta IPPROTO_UDP Ta Return 0.: ICMP messages will not be generated.
PF_INET Ta SOCK_STREAM Ta IPPROTO_SCTP Ta Return 0.: Send queued data and tear down association.
PF_INET Ta SOCK_STREAM Ta IPPROTO_TCP Ta Return 0.: Send queued data, wait for ACK, then send FIN.
PF_INET6 Ta SOCK_DGRAM Ta IPPROTO_SCTP Ta Return -1.: The global variable errno will be set to Er EOPNOTSUPP .
PF_INET6 Ta SOCK_DGRAM Ta IPPROTO_UDP Ta Return 0.: ICMP messages will not be generated.
PF_INET6 Ta SOCK_STREAM Ta IPPROTO_SCTP Ta Return 0.: Send queued data and tear down association.
PF_INET6 Ta SOCK_STREAM Ta IPPROTO_TCP Ta Return 0.: Send queued data, wait for ACK, then send FIN.

RETURN VALUES

Rv -std shutdown

ERRORS

The Fn shutdown system call fails if:

Bq Er EBADF: The Fa s argument is not a valid file descriptor.
Bq Er EINVAL: The Fa how argument is invalid.
Bq Er EOPNOTSUPP: The socket associated with the file descriptor Fa s does not support this operation.
Bq Er ENOTCONN: The Fa s argument specifies a SOCK_STREAM socket which is not connected.
Bq Er ENOTSOCK: The Fa s argument does not refer to a socket.

STANDARDS

The Fn shutdown system call is expected to comply with St -p1003.1g-2000 , when finalized.

HISTORY

The Fn shutdown system call appeared in BSD 4.2 The SHUT_RD , SHUT_WR and SHUT_RDWR constants appeared in St -p1003.1g-2000 .

AUTHORS

An -nosplit This manual page was updated by An Bruce M. Simpson Aq [email protected] to reflect how Fn 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 Fa s is bound after Fn shutdown is called.