> Don't overread the FAQ. It says nothing whatsoever about scanf.
> 
> I would love to explain a bit just to settle your concern. printf does not
> need to distinguish float's and double's as scanf does. According to what
> the C language standard terms "default argument promotion", any float
> matching against an ellipsis ("...") is implicitly promoted to double. So
> whether you pass a float or double to printf, it will always see a double.
> Therefore, it does not need a long modifier to distinguish the two types.
> 
May I ask a follow-up question:
So %lf in printf is somehow a "mis-implementation" in old compilers?