function GetFileSize(const FileName: String): LongInt;

var SearchRec: TSearchRec;

begin

  if FindFirst(ExpandFileName(FileName), faAnyFile, SearchRec) = 0 then

   Result := SearchRec.Size

  else

   Result := -1;

end;

//按书上所说,函数都是具有返回值的,它这else返回的是-1,超出2GB?

//那么这样对不对呢?

function GetFileSize(const FileName: String): Int64;

var SearchRec: TSearchRec;

begin

  if FindFirst(ExpandFileName(FileName), faAnyFile, SearchRec) = 0 then

   Result := SearchRec.Size

  else

   Result := -1;

end;