shutdown - shut down part of a full-duplex connection
Standard C library (libc, -lc)
#include <sys/socket.h>
int shutdown(int sockfd, int how);The shutdown() call causes all or part of a
full-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.
On success, zero is returned. On error, -1 is returned, and
errno is set to indicate the error.
sockfd is not a valid file descriptor.
An invalid value was specified in how (but see BUGS).
The specified socket is not connected.
The file descriptor sockfd does not refer to a socket.
POSIX.1-2008.
POSIX.1-2001, 4.4BSD (first appeared in 4.2BSD).
The constants SHUT_RD, SHUT_WR,
SHUT_RDWR have the value 0, 1, 2, respectively, and are
defined in <sys/socket.h> since glibc-2.1.91.
Checks for the validity of how are done in domain-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.