https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120698
--- Comment #1 from Sam James <sjames at gcc dot gnu.org> --- (In reply to Дилян Палаузов from comment #0) > https://gcc.gnu.org/onlinedocs/libstdc++/manual/configure.html says: > > > --enable-vtable-verify[default] > > which means, that by default vtable-verify is enabled (in libstdc++). To be fair, it does say "By default, this option is off." underneath. There's also some confusing bits here because --enable-xyz here is what you do in autoconf to write an option which is default *off*. Anyway, I agree the '[default]' is weird.