/**
 * @file
 *
 * Cheap, synchronous "is this PID still running?" probe.
 *
 * Signal `0` performs the permission and existence checks without delivering a
 * signal, on Windows as well as POSIX, so it costs nothing at teardown-poll
 * frequency. `EPERM` means the process exists but is owned by another user —
 * still alive, and the distinction matters: reading it as dead is how a
 * teardown convinces itself a process it could not touch is gone.
 */
/**
 * Checks whether a process is still running.
 *
 * @param pid - The PID to probe.
 * @returns `true` when the process exists.
 */
export declare function checkIsProcessAlive(pid: number): boolean;