What You Can Do with Capability Negotiation

Developers of applications need to be aware of a Source's capabilities and may influence the capabilities that the Source offers to the application's users. To do this, the application can perform capability negotiation. 

The application generally follows this process: 

1. Determine if the selected Source supports a particular capability.


2. Inquire about the Current Value for this capability. Also, inquire about the capability's Default Value and the set of Available Values that are supported by the Source for that capability.


3. Request that the Source set the Current Value to the application's desired value. The Current Value will be displayed as the current selection in the Source's user interface.


4. Limit, if needed, the Source's Available Values to a subset of what would normally be offered. For instance, if the application wants only black and white data, it can restrict the Source to transmit only that kind of data. If a limitation effects the Source's user interface, the Source should modify the interface to reflect those changes. For example, it may gray out options that are not available because of the application's restrictions.


5. Verify that the new values have been accepted by the Source.

See Also

CapGet(), CapGetCurrent(), CapGetDefault(), CapReset(), CapSet(), How to Negotiate Capability with Different Capability Container Types

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