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SA0011: Useless declaration with only a single member

Detects structures or enumerations with only a single member

Justification: No structures or enumerations with only a single member should be declared. Such declarations can be confusing for readers. A structure with only one element can be replaced by an alias type. An enumeration with only one element can be replaced by an constant.

PLCopen rule: CP22 / CP24

Importance: Low

Example 23. Example
{attribute 'qualified_only'}
{attribute 'strict'}
TYPE SINGLE_ENUM :
(
	OnlyOne := 1
);
END_TYPE
TYPE SINGLE_UNION :
UNION
	lrValue : LREAL;
END_UNION
END_TYPE
{attribute 'qualified_only'}
{attribute 'strict'}
TYPE SINGLE_ENUM :
(
	OnlyOne := 1
);
END_TYPE

Output in the Messages view:

  • sa_icon_message.png SA0011: Useless declaration 'SINGLE_ENUM': Struct/Enum with only a single member should not be used

  • sa_icon_message.png SA0011: Useless declaration 'SINGLE_UNION': Struct/Enum with only a single member should not be used

  • sa_icon_message.png SA0011: Useless declaration 'SINGLE_STRUCT': Struct/Enum with only a single member should not be used



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