imp.4p

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)imp.4p	8.1	9/11/90
.TH imp 4p VAX "" Unsupported
.SH Name
imp \- IMP raw socket interface
.SH Syntax
.B #include <sys/socket.h>
.br
.B #include <netinet/in.h>
.br
.B #include <netimp/if_imp.h>
.PP
.B s = socket(AF_IMPLINK, SOCK_RAW, IMPLINK_IP);
.SH Description
The raw 
.PN imp 
socket provides direct access to the
.MS imp 4
network interface.  Users send packets through
the interface using the 
.MS send 2
calls, and receive packets with the
.MS recv 2 ,
calls.  All outgoing packets must have space for an 1822 96-bit
leader on the front.  Likewise, packets received
by the user will have this leader on the front.  The
1822 leader and the legal values for the various fields
are defined in the include file
.RI < netimp/if_imp.h >.
.PP
The raw imp interface automatically installs the length
and destination address in the 1822 leader of all
outgoing packets; these need not be filled in by the user.
.SH Diagnostics
An operation on a socket may fail with one of the following
errors:
.TP 15
[EISCONN]
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.
.TP 15
[ENOTCONN]
when trying to send a datagram, but
no destination address is specified, and the socket hasn't been
connected.
.TP 15
[ENOBUFS]
when the system runs out of memory for
an internal data structure.
.TP 15
[EADDRNOTAVAIL]
when an attempt is made to create a 
socket with a network address for which no network interface
exists.
.SH See Also
intro(4n), inet(4f), imp(4)