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i want to process a text file line by line. In the olden days i loaded the file into a StringList : slFile := TStringList.Create(); slFile.LoadFromFile(filename); for i := 0 to slFile.Count-1 do begin oneLine := slFile.Strings[i]; //process the line end; Problem with that is once the file gets to be a few hundred megabytes, i have to allocate a huge chunk of memory; when really i only need enough memory to hold one line at a time. (Plus, you can't really indicate progress when you the system is locked up loading the file in step 1). The i tried using the native, and recommended, file I/O routines provided by Delphi: var f: TextFile; begin Reset(f, filename); while ReadLn(f, oneLine) do begin //process the line end; Problem with Assign is that there is no option to read the file without locking (i.e. fmShareDenyNone ). The former stringlist example doesn't support no-lock either, unless you change it to LoadFromStream : slFile := TStringList.Create; stream := TFileStream.Create(filename, fmOpenRead or fmShareDenyNone); slFile.LoadFromStream(stream); stream.Free; for i := 0 to slFile.Count-1 do begin oneLine := slFile.Strings[i]; //process the line end; So now even though i've gained no locks being held, i'm back to loading the entire file into memory. Is there some alternative to Assign / ReadLn , where i can read a file line-by-line, without taking a sharing lock? i'd rather not get directly into Win32 CreateFile / ReadFile , and having to deal with allocating buffers and detecting CR , LF , CRLF 's. i thought about memory mapped files, but there's the difficulty if the entire file doesn't fit (map) into virtual memory, and having to maps views

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