sprintf()ing: bug?

[Ilya Zakharevich <ilya@math.ohio-state.edu>]

I'm writing a "plotting" chunk of tutorial, and got the following
problem: I'm showing how to draw marking (like x/y-max/min on ploth())
on plots created with plotrecth().  I cannot.  I cannot find how to
make an analogue of rounding-sprintf() in PARI.

Should not this "work":

    ? \p 3
       realprecision = 9 significant digits (3 digits displayed)
    ? 2.34567
    %1 = 2.34
    ? print(2.34567)
    2.34
    ? Str(2.34567)
    %2 = "2.3456699997"

???

Ilya