value-stream.h File Reference

Value stream related callback functions. More...

Data Structures
struct	value_stream_s

Typedefs
typedef int(*	value_stream_on_subscription )(const char *const topic_path, const TOPIC_SPECIFICATION_T *specification, void *context)
	Callback for subscription. More...
typedef int(*	value_stream_on_unsubscription )(const char *const topic_path, const TOPIC_SPECIFICATION_T *const specification, NOTIFY_UNSUBSCRIPTION_REASON_T reason, void *context)
	Callback for unsubscription. More...
typedef int(*	value_stream_on_value )(const char *const topic_path, const TOPIC_SPECIFICATION_T *const specification, DIFFUSION_DATATYPE datatype, const DIFFUSION_VALUE_T *const old_value, const DIFFUSION_VALUE_T *const new_value, void *context)
	Callback for when a value has been received for the topic. More...
typedef void(*	value_stream_on_close )(void)
	Callback for when a value stream has been closed.
typedef void(*	value_stream_on_error )(const DIFFUSION_ERROR_T *error)
	Callback for when a value stream has encountered an error. More...

Detailed Description

Value stream related callback functions.

Typedef Documentation

typedef void(* value_stream_on_error)(const DIFFUSION_ERROR_T *error)

Callback for when a value stream has encountered an error.

Parameters

error

containing the error code and description of the error. The context to this will be the value stream's context.

typedef int(* value_stream_on_subscription)(const char *const topic_path, const TOPIC_SPECIFICATION_T *specification, void *context)

Callback for subscription.

Parameters

topic_path	the path of the topic subscribed to
specification	the specification of the topic
context	user-supplied context from the initial add_topic_from_specification call.

Returns

HANDLER_SUCCESS or HANDLER_FAILURE.

typedef int(* value_stream_on_unsubscription)(const char *const topic_path, const TOPIC_SPECIFICATION_T *const specification, NOTIFY_UNSUBSCRIPTION_REASON_T reason, void *context)

Callback for unsubscription.

Parameters

topic_path	the path of the topic subscribed to
specification	the specification of the topic
reason	the unsubscription reason
context	user-supplied context from the initial add_topic_from_specification call.

Returns

HANDLER_SUCCESS or HANDLER_FAILURE.

typedef int(* value_stream_on_value)(const char *const topic_path, const TOPIC_SPECIFICATION_T *const specification, DIFFUSION_DATATYPE datatype, const DIFFUSION_VALUE_T *const old_value, const DIFFUSION_VALUE_T *const new_value, void *context)

Callback for when a value has been received for the topic.

Parameters

topic_path	the path of the topic subscribed to
specification	the specification of the topic
datatype	the value stream datatype
old_value	the previous value for topic. Will be null for the initial call to on_value for a topic. It can also be null if the topic's data type supports null values. This value is intended to be called with its corresponding datatype value reader. i.e read_diffusion_string_value, read_diffusion_binary_value, read_diffusion_int64_value, etc.
new_value	the new value derived from the last update received from the server. It can be null if the topic's data type supports null values. This value is intended to be called with its corresponding datatype value reader. i.e read_diffusion_string_value, read_diffusion_binary_value, read_diffusion_int64_value, etc.
context	User-supplied context from the initial add_topic_from_specification call.

Returns

HANDLER_SUCCESS or HANDLER_FAILURE.