#define _GNU_SOURCE #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <inttypes.h> int main(void) { struct { struct file_handle fh; uint64_t cgroup_id; } handle; int mount_id; name_to_handle_at(AT_FDCWD, "/", &handle.fh, &mount_id, 0); return 0; }