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5.4 OPC UA JSON ToC Previous Next

5.4.8 Unions ToC Previous Next

Unions shall be encoded as JSON objects as shown in Table 34 for the reversible encoding.

Table 34 – JSON Object Definition for a Union

Name Description
SwitchField The identifier for the field in the Union which is encoded as a JSON number.
Value The value of the field encoded using the rules that apply to the data type.

For the non-reversible form, Unions values are encoded using the rule for the current value.

For example, instances of the union:

struct Union1
{
Byte Selector;

{
Int32 A;
Double B;
Char* C;
}
Value;
};

would be represented in reversible form as:

{ "SwitchField":2, "Value":3.1415 }

In non- reversible form, it is represented as:

3.1415

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