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High Performance OPC UA Server SDK
1.4.1.263
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High Performance OPC UA Server SDK
1.4.1.263
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Identifier for an item to read or to monitor. More...
#include <readvalueid.h>
Data Fields | |
| struct ua_nodeid | node_id |
| NodeId of a Node. | |
| uint32_t | attribute_id |
| Id of the Attribute. 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 |
| This parameter specifies the BrowseName of the DataTypeEncoding that the Server should use when returning the Value Attribute of a Variable. More... | |
Related Functions | |
| void | ua_readvalueid_init (struct ua_readvalueid *t) |
| Initialize an ua_readvalueid struct with a valid value. More... | |
| void | ua_readvalueid_clear (struct ua_readvalueid *t) |
| Clear all resources alloctated in an ua_readvalueid struct. More... | |
| int | ua_readvalueid_compare (const struct ua_readvalueid *a, const struct ua_readvalueid *b) |
| Compare two ua_readvalueid structs. More... | |
| int | ua_readvalueid_copy (struct ua_readvalueid *dst, const struct ua_readvalueid *src) |
| Create a copy of a ua_readvalueid struct. More... | |
Identifier for an item to read or to monitor.
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Clear all resources alloctated in an ua_readvalueid struct.
Frees allocated memory like arrays and resets numeric values. The ua_readvalueid struct itself is not freed and must be freed by the caller if required. This function always succeeds for a valid ua_readvalueid struct, that was validly decoded, initilized by ua_readvalueid_init or created with ua_readvalueid_copy.
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Compare two ua_readvalueid structs.
Compares the content of the ua_readvalueid struct a to the content of the ua_readvalueid 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_readvalueid structs, so it is well suited to not only determine equality, but also sort multiple instances of this struct.
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Create a copy of a ua_readvalueid struct.
Copy all fields from struct ua_readvalueid 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.
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Initialize an ua_readvalueid struct with a valid value.
After initialization the fields of the struct are set to valid and consistent values and can safley be accessed. An initialized ua_readvalueid struct can also be passed to ua_readvalueid_compare, ua_readvalueid_copy and ua_readvalueid_clear. This function will always succeed as long as an ua_readvalueid struct is passed to it.
| attribute_id |
Id of the Attribute.
This shall be a valid Attribute id.
The IntegerIds for the Attributes are defined in NodeAttributesMask.
| data_encoding |
This parameter specifies the BrowseName of the DataTypeEncoding that the Server should use when returning the Value Attribute of a Variable.
It is an error to specify this parameter for other Attributes.
A Client can discover what DataTypeEncodings are available by following the HasEncoding Reference from the DataType Node for a Variable.
OPC UA defines BrowseNames which Servers shall recognize even if the DataType Nodes are not visible in the Server address space. These BrowseNames are:
Each DataType shall support at least one of these encodings. DataTypes that do not have a true binary encoding (e.g. they only have a non-XML text encoding) should use the DefaultBinary name to identify the encoding that is considered to be the default non-XML encoding. DataTypes that support at least one XML-based encoding shall identify one of the encodings as the DefaultXML encoding. Other standards bodies may define other well-known data encodings that could be supported.
If this parameter is not specified then the Server shall choose either the DefaultBinary or DefaultXML encoding according to what Message encoding (see Part 6 of the OPC UA Specification) is used for the Session. If the Server does not support the encoding that matches the Message encoding then the Server shall choose the default encoding that it does support.
| 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 specified Attribute is not an array. However, if the specified Attribute is an array, and this parameter is null, then all elements are to be included in the range.