DSEND (2)
Send and receive LAM datalink
messages.
SYNOPSIS
#include <net.h>
#include <events.h>
int dsend (struct nmsg *header);
int dtry_send (struct nmsg *header);
int drecv (struct nmsg *header);
int dtry_recv (struct nmsg *header);
DESCRIPTION
These datalink functions pass a network message from one process to another
and are the basis for all forms of LAM network communication.
Although they can be invoked directly, they are most often called by the
network and transport functions.
The datalink functions do not supply message routing, buffering or
packetization.
The user supplies the event of the forwarding process and the message
length is restricted to MAXNMSGLEN, defined in <net.h>.
dsend()
and
drecv()
are typically used to send messages to, or receive messages from,
nearest neighbour nodes (see "Typical Usage").
dtry_send()
and
dtry_recv()
never cause the calling process to block.
The message is either immediately transferred,
or an error is immediately returned, indicating that the
process would have blocked.
All of the functions accept a pointer to a message structure
which is an extension of the local level message structure
used by ksend(2) and krecv(2).
The network message structure is defined in <net.h> as:
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