# Querying the capabilities of a protocol

Under ADI, to determine whether a protocol supports a feature or not, the application must attempt to use the feature, and watch for error codes indicating that the feature is not supported by the protocol. Under NCC, the application can query for a list of the protocol's features using nccQueryCapability.

Once an application has started a protocol, it can query its capabilities. The functions the application can use are indicated in the mask returned by nccQueryCapability.