struct mg_websocket_subprotocols;| Field | Type | Description | 
|---|---|---|
| nb_subprotocols | int | Number of websocket sub-protocol names following (>=0). | 
| subprotocols | const char ** | Array of websocket sub-protocol names (nb_subprotocols elements). | 
The structure mg_websocket_subprotocols is used to specify websocket sub-protocols supported by a websocket handler function.