int main() { __res_maybe_init(); // now expects GLIBC_PRIVATE version return 0; }
gcc -Wl,-u,__res_maybe_init@GLIBC_PRIVATE -o test main.c Where main.c is any valid C file. The linker will complain: undefined symbol --res-maybe-init version glibc-private
But for a , use a direct linker undefined reference : int main() { __res_maybe_init()