[Bug libstdc++/22542] ostringstream ignores fenv settings (incorrect output)

["pcarlini at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From pcarlini at suse dot de  2005-07-18 09:46 -------
> Ok, I'll reformulate it and I've even simplified the input.  4.5 is exactly
> representable in double precision, regardless of the active rounding precision.
> It should always be 4.5.  What I would like to do is to have that double
> precision input rounded to the number of digits given by .precision (1 in the
> example) using stringstreams, taking into account the rounding mode.

Certainly, the C++ standard doesn't mandate anything about the behavior in the
presence of those settings (among other things, it's C99 material): the behavior
is specified in terms of parameters to an underlying sprintf call. I seem to
understand that you want sprintf itself to take into account the rounding mode
when carrying out its own rounding. I'm not at all sure that the C standard
mandates that (i.e., I'm not at all sure that among the floating point
operations affected there is also the rounding internal to sprintf), but in
case this is a pure libc issue.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22542