https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108561
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |12.0 Resolution|--- |FIXED Status|UNCONFIRMED |RESOLVED --- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- I think this can be closed. std::endl is doing exactly what it's supposed to do, and ostream::flush has been fixed (15 years late) so that it won't flush a bad stream. I didn't backport the fix to gcc-11 and earlier because it *is* a change in observable behaviour, although maybe it's unequivocally a good change and would make sense to backport.