https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61038
--- Comment #9 from Daniel Krügler <daniel.kruegler at googlemail dot com> --- (In reply to Ben Longbons from comment #8) > What about multi-char constants, or are they not permitted in C++ UDLs? > Normally they get converted to int, so they're not *meaningful*, but ... There exists a core language issue for this: http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1723
