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.\" @(#)icmp.4 6.6 (Berkeley) 3/28/91
.Nd Internet Control Message Protocol
.Fd #include <sys/socket.h>
.Fd #include <netinet/in.h>
.Fn socket AF_INET SOCK_RAW proto
is the error and control message protocol used
and the Internet protocol family. It may be accessed
and diagnostic functions.
parameter to the socket call to create an
sockets are connectionless,
and are normally used with the
call may also be used to fix the destination for future
packets (in which case the
system calls may be used).
Outgoing packets automatically have an
them (based on the destination address).
Incoming packets are received with the
header and options intact.
A socket operation may fail with one of the following errors returned:
.Bl -tag -width [EADDRNOTAVAIL]
when trying to establish a connection on a socket which
already has one, or when trying to send a datagram with the destination
address specified and the socket is already connected;
when trying to send a datagram, but
no destination address is specified, and the socket hasn't been
when the system runs out of memory for
an internal data structure;
when an attempt is made to create a
socket with a network address for which no network interface