Currently, g++ does not emit the DW_AT_default_value attribute for formal parameters that have default values. I think it should; this is a prerequisite to letting gdb work with default arguments.
-- Summary: g++ does not emit DW_AT_default_value Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: debug AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: tromey at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42959