dtSearch Engine API Reference 2023.02
IIndexJob::StatusCurrentFileType Property
BSTR * StatusCurrentFileType;

File type of the file being indexed

While indexing is in process, the Status* properties provide easy access to information about the progress of the indexing job. When the indexing job was started with ExecuteInThread, the Status values will be updated each time IsThreadDone is called. These are only available when ExecuteInThread is called.