Record containg set of IO functions internaly used by image loaders/savers.

public TIOFunctions = record
  OpenRead: TOpenReadProc;
  OpenWrite: TOpenWriteProc;
  Close: TCloseProc;
  Eof: TEofProc;
  Seek: TSeekProc;
  Tell: TTellProc;
  Read: TReadProc;
  Write: TWriteProc;
  end;

Imaging (at line 329)