trace_pid_list_first
int trace_pid_list_first(struct trace_pid_list *pid_list, unsigned int *pid);
if (!trace_pid_list_first(pid_list, &first) ||
!trace_pid_list_first(no_pid_list, &first))
if (trace_pid_list_first(pid_list, &first) < 0)
ret = trace_pid_list_first(filtered_pids, &pid);