Echelon Neuron C - Manual (Page 218)

198 Built-In Variables, Objects, Symbols, and Semaphore
Built-In Objects
The following sections list the Neuron C built-in objects alphabetically, providing
relevant syntax information and a detailed description of each function.
msg_in Object
The msg_in object contains an incoming application or foreign-frame message.
The type is a structure predefined in Neuron C as shown below:
typedef enum {ACKD, UNACKD_RPT,
UNACKD, REQUEST} service_type;
struct {
int code;
int len;
int data[MAXDATA];
boolean authenticated;
service_type service;
msg_in_addr addr;
boolean duplicate;
unsigned rcvtx;
} msg_in;
The various fields of the msg_in object are:
code
Message code for the incoming message.
len Length of message data in bytes.
data Message data.
authenticated TRUE if authenticated, message has passed challenge.
service Service type for the incoming message.
addr Source address of this message, and address through
which the message was received. See <msg_addr.h>
include file.
duplicate Message is a duplicate request. See Idempotent Versus
Non-Idempotent Requests in the Neuron C Programmer's
Guide .
rcvtx The index into the receive transaction database for this
message.
See Format of an Incoming Message in Chapter 6, How Devices Communicate
Using Application Messages, of the Neuron C Programmer's Guide for more
information about this structure.
msg_out Object
The msg_out object contains an outgoing application or foreign frame message.
The type is a structure predefined in the Neuron C as shown below:
typedef enum {FALSE, TRUE} boolean;
typedef enum {ACKD, UNACKD_RPT,
UNACKD, REQUEST} service_type;