Echelon OpenLDV - Manual (Page 25)

OpenLDV Programmer’s Guide 17
• The ldv_set_device_info() function allows you to modify certain
information for a device.
• The ldv_get_matching_devices() function allows you retrieve a list of
devices that match a specified set of capabilities. For example, you can
determine which devices operate at Layer 2 or Layer 5, you can
determine which devices are IP-852 devices or channels, or you can
determine which devices are protocol analyzers.
• The ldv_free_device_info(), ldv_free_driver_info(), and
ldv_free_matching_devices() functions release resources allocated by
the ldv_get_device_info(), ldv_get_driver_info(), and
ldv_get_matching_devices() functions.
• The ldv_open_cap() function allows you to open a device with a specified
capability enabled, if the capability is supported by the device. For
example, you could open a U10 USB network interface with Layer 2
operation or with Layer 5 operation. However, only local devices and
static xDriver RNI devices that use the default xDriver lookup extension
can supply their device capabilities. xDriver RNIs that use a custom
lookup extension are either not available or report as having unknown
capabilities.
See The OpenLDV API on page 15 for a description of these functions and the
rest of the OpenLDV functions.
Using the OpenLDV API
The basic code flow for an OpenLDV application includes the following four
functions, which comprise the basis of all OpenLDV applications:
• ldv_open()
• ldv_read()
• ldv_write()
• ldv_close()
An application can call the ldv_read() and ldv_write() functions in any order,
and at any time after opening the network interface, but before closing the
network interface.
The following sections describe each of the API functions in detail. The syntax
for each function includes a table that describes the following information:
• Each parameter required for the function. The parameter data type does
not appear in the table, but is shown in the syntax for the function.
• The direction for each parameter:
o Input: Input parameters provide data to the OpenLDV function.
You must supply an appropriate value for each input parameter.
o Output: Output parameters provide data to your application
from the OpenLDV function. You must supply an appropriately
sized variable or buffer for each output parameter.
• A description of each parameter.