Compiling the attached C++0x program fails on 4.5 but is successful in 4.4. I think the root cause is the missing nullptr support but that doesn't make it any more useful for 4.5.
-- Summary: Not possible to compare unique_ptr with 0 Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: gcc at magfr dot user dot lysator dot liu dot se http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42925