E2155 Type '%s' needs finalization - not allowed in file type (Object Pascal)
Certain types are treated specially by the compiler on an internal basis in that they must be correctly finalized to release any resources that they might currently own. Because the compiler cannot determine what type is actually stored in a record's variant section at run time, it is not possible to guarantee that these special data types are correctly finalized.
program Produce; type Data = record name : string; end; var inFile : file of Data; begin end.
String is one of those data types which need finalization, and as such they cannot be stored in a File type.
program Solve; type Data = record name : array [1..25] of Char; end; var inFile : file of Data; begin end.
One simple solution, for the case of String, is to redeclare the type as an array of characters. For other cases which require finalization, it becomes increasingly difficult to maintain a binary file structure with standard Pascal features, such as 'file of'. In these situations, it is probably easier to write specialized file I/O routines.