cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration stdio/ungetc.c -o stdio/ungetc -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv
relibc getrlimit(3, 0x7ffffffffc80): not implemented
relibc getrlimit(3, 0x7ffffffffba0): not implemented
relibc getrlimit(9, 0x7ffffffffb60): not implemented
relibc getrlimit(9, 0x7ffffffffb90): not implemented
relibc getrlimit(5, 0x7ffffffffb90): not implemented
relibc getrlimit(9, 0x7ffffffffb60): not implemented
stdio/ungetc.c: In function 'main':
stdio/ungetc.c:10:20: error: implicit declaration of function 'fmemopen'; did you mean 'freopen'? [-Werror=implicit-function-declaration]
   10 |         FILE* fp = fmemopen(buf, sizeof(buf), "r");
      |                    ^~~~~~~~
      |                    freopen
stdio/ungetc.c:10:20: warning: initialization of 'FILE *' {aka 'struct FILE *'} from 'int' makes pointer from integer without a cast [-Wint-conversion]
cc1: some warnings being treated as errors