/* C99 6.10.8 para 4: None of [the predefined macro names] shall be the subject of a #define or an #undef preprocessing directive. We pass -fno-show-column as otherwise dejagnu gets confused. */ /* { dg-do preprocess } */ /* { dg-options "-fno-show-column" } */ #undef __DATE__ /* { dg-warning "undefining" "__DATE__" } */ #undef __TIME__ /* { dg-warning "undefining" "__TIME__" } */ #undef __FILE__ /* { dg-warning "undefining" "__FILE__" } */ #undef __LINE__ /* { dg-warning "undefining" "__LINE__" } */ #undef __STDC__ /* { dg-warning "undefining" "__STDC__" } */ /* These should be protected from #undef, but aren't, because they are set with normal #define commands - and on top of that, some of them are library properties, outside our control. To consider: warn about undefining/redefining any identifier beginning with __STDC_ . __STDC_HOSTED__ __STDC_VERSION__ __STDC_IEC_559__ __STDC_IEC_559_COMPLEX__ __STDC_ISO_10646__ */