shutdown() — Shut down all or part of a duplex connection

X/Open:

#define _XOPEN_SOURCE_EXTENDED 1
#include <sys/socket.h>

int shutdown(int socket, int how);

Berkeley sockets:

#define _OE_SOCKETS
#include <sys/socket.h>

long shutdown(int *s, int how);

The shutdown() function shuts down all or part of a duplex connection.

Parameter

Description

socket

The socket descriptor.

how

The condition of the shutdown. The values 0, 1, or 2 set the condition. how sets the condition for shutting down the connection to the socket indicated by socket.

how can have a value of:

• SHUT_RD, which ends communication from the socket indicated by socket.
• SHUT_WR, which ends communication to the socket indicated by socket.
• SHUT_RDWR, which ends communication both to and from the socket indicated by socket.

If unsuccessful, shutdown() returns -1 and sets errno to one of the following values:

Error Code

Description

EBADF

socket is not a valid socket descriptor.

EINVAL

The how parameter was not set to one of the valid values.

ENOBUFS

Insufficient system resources are available to complete the call.

ENOTCONN

The socket is not connected.

ENOTSOCK

The descriptor is for a file, not for a socket.