[Bug libstdc++/49048] New: setprecision rounding fails in some cases

[s.cecilio at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49048

           Summary: setprecision rounding fails in some cases
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: s.cecilio@gmail.com


cecilio@pp1:~$ gcc --version
gcc (Ubuntu 4.4.3-4ubuntu5) 4.4.3

I'm having problems with truncation. For instance, following code:

        cout << "test precision 5798.12500: "
                  << fixed << setprecision(2) << setfill(' ')
                  << setw(10) << 5798.12500 << endl;

        cout << "test precision 5798.87500: "
                  << fixed << setprecision(2) << setfill(' ')
                  << setw(10) << 5798.87500 << endl;

Generates inconsistent results: 5798.12 (wrong, should be 5798.13) and 5798.88
(right).
In first case rounds up and in second, down.

The same code, compiled with Microsft Visual Studio, produces the right results
in the same machine.