LogChangeEventFilter is used to alter the event-notification filter that is associated with an event-notification request. In addition to changing the filter, you can specify current event-notification entries that are to be purged before the filter change takes effect.

#define INCL_LOGGING
#include <os2.h>

ULONG     service;
PVOID     pChangeEventFilter;
APIRET    rc;

rc = LogChangeEventFilter(service, pChangeEventFilter);