#include opcapi.h
int opcif_unregister(
int interface_id, /* in */
long cond_id /* in */
);
Parameters
interface_id
cond_id
Description
To cancel prior registrations for messages, the external
application calls opcif_unregister()
with the value of
reg_cond
that was specified in the call to the
registration API. As the registration mechanism is a positive
filter, removing a registration condition does not mean that
messages matched by this condition are filtered out after
opcif_unregister()
is called. Instead, just the
positive filter condition is cancelled.
By unregistering a condition for message events or application responses, information matching the unregistered condition will no longer received.
Return Values
OPC_ERR_OK
OPC_ERR_CANT_INIT
OPC_ERR_INVALID_INTERFACE_ID
OPC_ERR_CANT_INFORM_MSGM
Versions
HPOM for Windows 8.00 and higher