Echelon OpenLDV - Manual (Page 60)

52 Using the OpenLDV API
Return Code
Numeric
Value Description
LDV_BUFFER_CONFIGURATION_TOO_LARGE 45 The specified buffer
configuration is too large to fit
in the available space.
Applies to APP/NET buffers
on the network interface.
LDV_WARNING_APP_BUFFER_SIZE_MISMATCH 46 Warning message that the
buffer size mismatch might
cause problems.
Applies to APP/NET buffers
on the network interface.
Example: A Simple OpenLDV Application
The following code sample shows a very simple OpenLDV application that works
with an Echelon USB Network Interface. In this example, the application
performs the following tasks:
1. Opens the network interface
2. Writes a Query Status command to the interface to retrieve the
interface’s current state; from the current state, extracts the network
interface’s error log and prints a message
3. Reads the response to the Query Status command
4. Closes the network interface
5. Shuts down the OpenLDV driver
A real application would perform the same basic set of tasks, but typically for
additional devices beyond just the network interface. Also, a real application
would query the local device database to determine which network interface to
use; this example simply uses LON1. An application might also define the
network address for the network interface and for network devices; this example
uses local network addressing.
This example uses definitions found in the OpenLDVdefinitions.h header file,
which is included with the OpenLDV Developer Example; see Chapter 4, The
OpenLDV Developer Example, on page 89. It also includes the NetMgmt.h
header file, which is installed to the L ON W ORKS \NeuronC\Include directory
with the NodeBuilder FX Developer’s Kit or the Mini FX Evaluation Kit.
// Include Windows header file
#include <windows.h>
// Include OpenLDV header file
#include “ldv32.h”
// Include Neuron C Network Management header file
// (contains definition for ND_query_status_response)
#include “netmgmt.h”