Once the socket connection has been established, the ANNO API is used to provide the high level calls to pass annotation requests and responses between the engine and the annotation server:

• ANNO_stackInit initialises the annotation interface.
• ANNO_open opens a connection from the annotation server to the engine.
• ANNO_registerReceiveFn registers a callback function for receiving annotation requests.
• ANNO_getRequestInfo returns information about an annotate request.
• ANNO_sendResponse sends an annotate response over an open connection.
• ANNO_stackReset resets the annotation interface.
• ANNO_close closes a connection through the socket stack.