Pointer(s)^ versus s[1]

Question

In a function that reads data (data meaning exclusively strings) from disk, which should I prefer? Which is better?

A) DiskStream.Read(Pointer(s         


        

Answer 1

If there is ever any chance that your function will be called with a Count of 0, then A) will work with Pointer(s)^ simply evaluating to nil while B) will crash with a range check exception.

If you want to use B) and still handle counts of 0 gracefully, you should use:

function TMyStream.ReadChars(out s: AnsiString; const Count: Integer): Boolean; 
begin
 SetLength(s, Count);
 Result := (Count = 0)  or (Read(s[1], Count) = Count);
end;