[Bug libstdc++/27904] New: operator>> to floating point variable does not support "inf", "infinity", or "nan"

["ian at airs dot com" <gcc-bugzilla at gcc dot gnu dot org>]

On GNU/Linux, and several other operating systems, the strtod function will
accept the strings "inf" and "infinity" for an infinite value, and the string
"nan" for a NaN (the tests are case insensitive).  This is a convenient way to
specify an infinite or NaN floating point value from the command line or in an
input file.

Unfortunately, this does not work with operator>> in the current libstdc++. 
Here is a test case which I believe should pass, as a quality of implementation
issue.  It currently aborts.  I haven't yet tested it with libstdc++ v2, but
inspection suggests that it would have worked.

#include <sstream>
#include <cmath>

int
main ()
{
  std::istringstream sinf ("inf");
  double d;
  sinf >> d;
  if (!sinf || !isinf (d))
    abort ();

  std::istringstream sinfinity ("infinity");
  sinfinity >> d;
  if (!sinfinity || !isinf (d))
    abort ();

  std::istringstream snan ("nan");
  snan >> d;
  if (!snan || !isnan (d))
    abort ();

  exit (0);
}


-- 
           Summary: operator>> to floating point variable does not support
                    "inf", "infinity", or "nan"
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ian at airs dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27904