A structure that is defined as the type of the nodesToRead parameter of the HistoryRead Service. More...

#include <historyreadvalueid.h>

Data Fields
struct ua_nodeid	node_id
	The nodeId to be read depends on HistoryReadDetails. More...

struct ua_string	index_range
	This parameter is used to identify a single element of an array, or a single range of indexes for arrays. More...

struct ua_qualifiedname	data_encoding
	A QualifiedName that specifies the data encoding to be returned for the Value to be read. More...

struct ua_bytestring	continuation_point
	For each NodeToRead this parameter specifies a continuation point returned from a previous HistoryRead call, allowing the Client to continue that read from the last value received. More...

Related Functions
void	ua_historyreadvalueid_init (struct ua_historyreadvalueid *t)
	Initialize an ua_historyreadvalueid struct with a valid value. More...

void	ua_historyreadvalueid_clear (struct ua_historyreadvalueid *t)
	Clear all resources alloctated in an ua_historyreadvalueid struct. More...

int	ua_historyreadvalueid_compare (const struct ua_historyreadvalueid a, const struct ua_historyreadvalueid b)
	Compare two ua_historyreadvalueid structs. More...

int	ua_historyreadvalueid_copy (struct ua_historyreadvalueid dst, const struct ua_historyreadvalueid src)
	Create a copy of a ua_historyreadvalueid struct. More...

Detailed Description

A structure that is defined as the type of the nodesToRead parameter of the HistoryRead Service.

Friends And Related Function Documentation

void ua_historyreadvalueid_clear ( struct ua_historyreadvalueid * t )

Frees allocated memory like arrays and resets numeric values. The ua_historyreadvalueid struct itself is not freed and must be freed by the caller if required. This function always succeeds for a valid ua_historyreadvalueid struct, that was validly decoded, initilized by ua_historyreadvalueid_init or created with ua_historyreadvalueid_copy.

int ua_historyreadvalueid_compare	(	const struct ua_historyreadvalueid *	a,
		const struct ua_historyreadvalueid *	b
	)

Compares the content of the ua_historyreadvalueid struct a to the content of the ua_historyreadvalueid struct b. If a is smaller than b, an integer less than zero is returned, if a is bigger than b, an integer greater than zero is returned. If both structs are equal zero is returned.

This function creates a total order on ua_historyreadvalueid structs, so it is well suited to not only determine equality, but also sort multiple instances of this struct.

int ua_historyreadvalueid_copy	(	struct ua_historyreadvalueid *	dst,
		const struct ua_historyreadvalueid *	src
	)

Copy all fields from struct ua_historyreadvalueid src to dst. Creates a deep copy so all content is recusively copied and both src and dst can be used and must be freed separately.

dst is not cleared before the copy operation, so it must not have any allocated data. It may or may not be initilized by the caller before copy.

Returns: Zero on success or ua_statuscode on failure.

void ua_historyreadvalueid_init ( struct ua_historyreadvalueid * t )

After initialization the fields of the struct are set to valid and consistent values and can safley be accessed. An initialized ua_historyreadvalueid struct can also be passed to ua_historyreadvalueid_compare, ua_historyreadvalueid_copy and ua_historyreadvalueid_clear. This function will always succeed as long as an ua_historyreadvalueid struct is passed to it.

Field Documentation

continuation_point

For each NodeToRead this parameter specifies a continuation point returned from a previous HistoryRead call, allowing the Client to continue that read from the last value received.

The HistoryRead is used to select an ordered sequence of historical values or events. A continuation point marks a point in that ordered sequence, such that the Server returns the subset of the sequence that follows that point.

A null value indicates that this parameter is not used.

This continuation point is described in more detail in Part 11 of the OPC UA Specification.

data_encoding

A QualifiedName that specifies the data encoding to be returned for the Value to be read.

See ua_readvalueid for a definition on how to specify the data encoding.

The parameter is ignored when reading history of Events.

index_range

This parameter is used to identify a single element of an array, or a single range of indexes for arrays.

If a range of elements is specified, the values are returned as a composite. The first element is identified by index 0 (zero).

This parameter is null if the value is not an array. However, if the value is an array, and this parameter is null, then all elements are to be included in the range.

node_id

The nodeId to be read depends on HistoryReadDetails.

If HistoryReadDetails is

RAW, PROCESSED, MODIFIED or ATTIME: The nodeId of the Nodes whose historical values are to be read. The value returned shall always include a timestamp.
EVENTS: The NodeId of the Node whose Event history is to be read.

If the Node does not support the requested access for historical values or historical events, the appropriate error response for the given node shall be generated.

The documentation for this struct was generated from the following files:

C:/work/embeddedstack/src/uabase/structure/historyreadvalueid.h
C:/work/embeddedstack/src/uabase/structure/historyreadvalueid.c

Data Fields

Related Functions

Detailed Description

Friends And Related Function Documentation

Field Documentation