Floating point limit format - %fl
Specifies the lower and upper limits (as DOUBLE PRECISION arguments) for
subsequent %rf formats. The lower and upper limits are supplied as
DOUBLE PRECESION x
The lower limit should be specified with care unless %co[CHECK_ON_FOCUS_LOSS] is
used. If, for example, the lower limit were 500.0 and the user desired to enter
the value 525.0, the number would be rejected as soon as the first digit 5 is
entered. If CHECK_ON_FOCUS_LOSS is not used then the lower limit should be
chosen to avoid this problem.
%`fl can be used after %rf in order to remove the limits for the next %rf.