verify_fdinfo
ret = verify_fdinfo(fd, &err, "eventfd-semaphore: ", 19, "1\n");
r = verify_fdinfo(pidfd, &err, "NSpid:", 6, "\t0\n");
verify_fdinfo(a.fd, &err, "NSpid:", 6, "\t%d\t%d\n", a.pid, 1);
verify_fdinfo(b.fd, &err, "NSpid:", 6, "\t%d\t%d\n", b.pid, 1);
verify_fdinfo(a.fd, &err, "Pid:", 4, "\t-1\n");
verify_fdinfo(a.fd, &err, "NSpid:", 6, "\t-1\n");