P2021¶

Code: P2021
Message: Structure field references undeclared type

Structure field references undeclared type

This error occurs when a structure field declaration references a type that has not been declared or is not available in the current scope.

Example¶

The following code will generate error P2021:

TYPE
    MyStruct : STRUCT
        field1 : UNKNOWN_TYPE;  (* UNKNOWN_TYPE is not declared *)
        field2 : INT;
    END_STRUCT;
END_TYPE

The error occurs because UNKNOWN_TYPE has not been declared as a valid type in the program.

To fix this error, ensure the field type is properly declared:

TYPE
    MyStruct : STRUCT
        field1 : INT;  (* Use a valid elementary type *)
        field2 : INT;
    END_STRUCT;
END_TYPE

Or declare the custom type before using it:

TYPE
    CustomType : INT(0..100);

    MyStruct : STRUCT
        field1 : CustomType;  (* Now CustomType is declared *)
        field2 : INT;
    END_STRUCT;
END_TYPE