1 /* C99 6.10.8 para 4: None of [the predefined macro names] shall be 2 the subject of a #define or an #undef preprocessing directive. We 3 pass -fno-show-column as otherwise dejagnu gets confused. */ 4 5 /* { dg-do preprocess } */ 6 /* { dg-options "-fno-show-column" } */ 7 8 #undef __DATE__ /* { dg-warning "undefining" "__DATE__" } */ 9 #undef __TIME__ /* { dg-warning "undefining" "__TIME__" } */ 10 #undef __FILE__ /* { dg-warning "undefining" "__FILE__" } */ 11 #undef __LINE__ /* { dg-warning "undefining" "__LINE__" } */ 12 #undef __STDC__ /* { dg-warning "undefining" "__STDC__" } */ 13 14 /* These should be protected from #undef, but aren't, because they 15 are set with normal #define commands - and on top of that, some 16 of them are library properties, outside our control. To consider: 17 warn about undefining/redefining any identifier beginning with 18 __STDC_ . 19 20 __STDC_HOSTED__ 21 __STDC_VERSION__ 22 __STDC_IEC_559__ 23 __STDC_IEC_559_COMPLEX__ 24 __STDC_ISO_10646__ 25 */ 26