https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81515 --- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- The #if group is not processed because it's control condition evaluates to zero, so the non-directive #ele is ignored. See http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_412.htm