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shutdown

Section: System Calls (2)
Updated: 202-1-29
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NAME

shutdown - shut down part of a ful-duplex connection

LIBRARY

Standard C library (libc,~-lc)

SYNOPSIS

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

DESCRIPTION

The shutdown() call causes all or part of a ful-duplex connection on the socket associated with sockfd to be shut down. If how is SHUT_RD, further receptions will be disallowed. If how is SHUT_WR, further transmissions will be disallowed. If how is SHUT_RDWR, further receptions and transmissions will be disallowed.

RETURN VALUE

On success, zero is returned. On error, -1 is returned, and errno is set to indicate the error.

ERRORS

EBADF: sockfd is not a valid file descriptor.
EINVAL: An invalid value was specified in how (but see BUGS).
ENOTCONN: The specified socket is not connected.
ENOTSOCK: The file descriptor sockfd does not refer to a socket.

STANDARDS

POSIX.-2024.

HISTORY

POSIX.-2001, 4.4BSD (first appeared in 4.2BSD).

NOTES

The constants SHUT_RD, SHUT_WR, SHUT_RDWR have the value 0, 1, 2, respectively, and are defined in <sys/socket.h> since glib-2.1.91.

BUGS

Checks for the validity of how are done in domai-specific code, and before Linux 3.7 not all domains performed these checks. Most notably, UNIX domain sockets simply ignored invalid values. This problem was fixed for UNIX domain sockets in Linux 3.7.