CBFS Filter 2020 Node.js Edition

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Altitude Property

The altitude the class's system driver should use when operating in minifilter mode.

Syntax

 cbfilter.getAltitude([callback])
 cbfilter.setAltitude( altitude, [callback])

Default Value

-1

Callback

The 'callback' parameter specifies a function which will be called when the operation completes (or an error is encountered). If the 'callback' parameter is not specified, then the method will block and will not return until the operation completes (or an error is encountered).

The callback for the getAltitude([callback]) method is defined as:

function(err, data){ }

'err' is the error that occurred. If there was no error, then 'err' is 'null'.

'data' is the value returned by the method.

The callback for the setAltitude([callback]) method is defined as:

function(err){ }

'err' is the error that occurred. If there was no error, then 'err' is 'null'.

'err' has 2 properties which hold detailed information:

err.code
err.message

Remarks

This property specifies the altitude that the class's system driver should use when operating in minifilter mode (i.e., when the FilterMode property is set to FS_FILTER_MODE_MINIFILTER). A driver's altitude determines its absolute position in the stack of filter drivers; drivers with higher altitudes are attached towards the top of the stack, closer to user mode, which allows them to process requests earlier.

Microsoft manages and assigns filesystem minifilter driver altitudes directly, so an application-specific altitude value must be obtained from Microsoft before an application is deployed in production. Please refer to the Driver Altitudes topic for more information. During development, an appropriate arbitrary value, such as 360000 (which isn't registered with Microsoft), can be used.

If this property is queried before an altitude has been set (via this property or the Install method), it will return -1.

Note: This property cannot be changed when Active is true. Additionally, the Initialize method must be called before attempting to get or set this property's value, which is stored in the registry.

This property is not available at design time.

Data Type

Integer

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CBFS Filter 2020 Node.js Edition - Version 20.0 [Build 8164]