https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90081
Martin Sebor <msebor at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- URL| |http://www.open-std.org/jtc | |1/sc22/wg14/www/docs/summar | |y.htm#dr_456 CC| |msebor at gcc dot gnu.org --- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> --- UINT8_C(-5) isn't valid but expanding the macros to their arguments isn't conforming either. C11 DR #456 suggests compiler magic is necessary to make the macros correct: http://www.open-std.org/jtc1/sc22/wg14/www/docs/summary.htm#dr_456 (Also see C99 DR 209: http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_209.htm).