cc -pipe -O   -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations fcntl/struct-f_owner_ex-pid.c -o fcntl/struct-f_owner_ex-pid -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt  -lrt -lcrypt
fcntl/struct-f_owner_ex-pid.c:2:17: error: 'struct f_owner_ex' declared inside parameter list will not be visible outside of this definition or declaration [-Werror]
 void foo(struct f_owner_ex* bar)
                 ^~~~~~~~~~
fcntl/struct-f_owner_ex-pid.c: In function 'foo':
fcntl/struct-f_owner_ex-pid.c:4:19: error: dereferencing pointer to incomplete type 'struct f_owner_ex'
  pid_t *qux = &bar->pid;
                   ^~
cc1: all warnings being treated as errors