[Bug libstdc++/11460] New: Incorrect use of int_type in strstreambuf::pbackfail

[peturr02 at ru dot is]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11460

           Summary: Incorrect use of int_type in strstreambuf::pbackfail
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: libstdc++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: peturr02 at ru dot is
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu

strstreambuf::pbackfail uses the construct
  else if (c == static_cast<int_type>(gptr()[-1])) 
where c is of type int_type. This always evaluates to false when
gptr()[-1] < 0, since values of int_type that correspond to actual
characters are >= 0. To fix, this should be changed to
  else if (c == static_cast<unsigned char>(gptr()[-1])) 
or, even better
  else if (c == traits_type::to_int_type(gptr()[-1]))