add_filter

Description:

public uint add_filter (string? classes, Caps? caps)

Adds a filter for which Device will be monitored, any device that matches all these classes and the Caps will be returned.

If this function is called multiple times to add more filters, each will be matched independently. That is, adding more filters will not further restrict what devices are matched.

The Caps supported by the device as returned by get_caps are not intersected with caps filters added using this function.

Filters must be added before the DeviceMonitor is started.

Parameters:

this	a device monitor
classes	device classes to use as filter or `null` for any class
caps	the Caps to filter or `null` for ANY

Returns:

The id of the new filter or 0 if no provider matched the filter's classes.