/** Record the independent Linux process group created for one managed Pi turn. */
export declare function managedProcessGroupStart(pid: number): string | null;
/** A recycled leader PID must never target a new process group. */
export declare function signalManagedProcessGroup(pid: number, start: string, signal: NodeJS.Signals): boolean;
export declare function forgetManagedProcessGroup(pid: number, start: string): void;