Start filtering filesystem operations.
This method attaches the filter, causing the class's system driver to start filtering filesystem operations according to the filter rules currently present. Rules can be added and removed both before and after this method is called, so long as the Initialize method is called before doing anything else.
The Timeout parameter specifies how many milliseconds the driver should wait for events to execute before releasing or cancelling the underlying OS requests; please refer to the Timeouts topic for more information. Valid values are 0, which disables event timeouts, and values greater than or equal to 3000. When event timeouts are in effect, event handlers can call ResetTimeout to reset the timer if they require additional time to complete.
This method can fail for a number of reasons, including (but not limited to) the following:
- If the class's system driver has not been properly installed, or is awaiting a system reboot (as indicated by the return value of Install), this method fails with an ERROR_FILE_NOT_FOUND (2) error code.
- If the Initialize method has not been called yet, this method fails with an ERROR_NOT_READY (21) error code.
- If the filter is already Active, this method fails with an ERROR_CONNECTION_ACTIVE (1230) error code.
- If an invalid value is passed for Timeout, this method fails with an ERROR_IMPLEMENTATION_LIMIT (1292) error code.