Echelon OpenLDV - Manual (Page 34)

26 Using the OpenLDV API
Table 13. ldv_open_cap() Parameters
Parameter Direction Description
szDevice Input The network interface with which to establish
communication. For example, “LON1” could be used to
identify a U10, PCLTA-10, or PCLTA-21 network interface.
Or, “X.Default.1MainStreet” could be used to identify a
SmartServer that will be opened through xDriver.
pHandle Output A pointer to a variable that you can use to identify the
network interface with the other OpenLDV functions. This
handle is valid only if the function returns LDV_OK.
nDeviceCaps Input The requested operational mode for the network interface.
For example, a USB network interface can be opened as a
Layer 2 or a Layer 5 network interface by specifying the
appropriate LDVDeviceCaps value (LDV_DEVCAP_L2 or
LDV_DEVCAP_L5).
hWnd Input The Windows handle for the session state change or
attachment notification messages, where available (for
example, from an xDriver device or a USB network
interface).
If NULL, no notification messages are sent.
tag Input Correlates notification messages with sessions. This tag is
supplied as the LPARAM parameter of all session state
change messages.
Remarks
This function is an extended version of the ldv_open() and ldvx_open()
functions that additionally allows you to request the operational mode in which
to open the specified device. If supported by the network interface, this function
allows you to request Layer 2 or Layer 5 operational mode, or request that
communications with the device (the ldv_read() and ldv_write() functions) use
the SICB format or the extended LdvEx format (which includes the SICB data).
See Application Buffer Structure on page 58 for a description of the SICB and
LdvEx formats.
This function returns LDV_OK if the network interface is successfully opened.
In this case, the function also returns a handle that you can use to identify the
network interface with the other OpenLDV functions. Use the ldv_close()
function to close the session with the network interface.
If the device does not support the requested capability, the error
LDV_CAPABILITY_NOT_SUPPORTED is returned, and the device is not
opened. Note that remote network interfaces (RNIs) are Layer 5 only. Protocol
analyzer usage (supported by SmartServers and i.LON 600 RNI devices) is
similar to Layer 2 (but receive-only). IP-852 channels cannot be opened by an
OpenLDV application.