dl-breadcrumbs__homedl-breadcrumb-item__separatorConfiguration and programmingdl-breadcrumb-item__separatorProgramming with CODESYSdl-breadcrumb-item__separator...dl-breadcrumb-item__separatorCODESYS Development Systemdl-breadcrumb-item__separatorReference, Programmingdl-breadcrumb-item__separatorError Messages and Warningsdl-breadcrumb-item__separatorCompiler error C0018
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Compiler error C0018dl-permalink__symbolPermalink

Message: <expression> is not a valid assignment target

Possible error cause: An expression with no write permission is on the left side of an assignment. Example: a constant.

Error correction: Assign only to variables that have write access.

Example of the error:

PROGRAM PLC_PRG
VAR
	i: INT;
END_VAR
VAR CONSTANT
	j: INT := 0;
END_VAR

j := i;

--> C0018:  'j' is not a valid assignment target