/**
 * Exit status for "our output pipe is gone". 128 + SIGPIPE(13), the shell
 * convention for death by broken pipe, so a supervisor can tell this apart
 * from an ordinary crash.
 */
export declare const BROKEN_PIPE_EXIT_CODE = 141;
/** Structural subset of `process.stdout` the safety net inspects and watches. */
type StdioStream = {
    destroyed?: boolean;
    writableEnded?: boolean;
    on?: (event: "error", listener: (err: unknown) => void) => unknown;
    off?: (event: "error", listener: (err: unknown) => void) => unknown;
};
export interface SafetyNetOptions {
    /** Emits the non-fatal diagnostic line. Routed through the LogStore. */
    log: (line: string) => void;
    /** Terminates the process. Defaults to `process.exit`. */
    exit?: (code: number) => void;
    /** Stream whose death makes logging pointless. Defaults to `process.stdout`. */
    stdout?: StdioStream;
    /**
     * Exit when the output pipe dies. Default `true` here, but the caller
     * decides: only code that owns the process should pass `true`. See
     * `ServeOptions.exitOnBrokenPipe`, which defaults to `false` for that
     * reason. Silencing the sinks is unaffected either way.
     */
    exitOnBrokenPipe?: boolean;
}
export type SafetyNetHandler = (label: "uncaughtException" | "unhandledRejection", err: unknown) => void;
/**
 * Build the handler shared by both process-level listeners.
 *
 * Exposed separately from {@link installProcessSafetyNet} so its policy can be
 * tested without registering real listeners on the test runner's process.
 */
export declare function createSafetyNetHandler(opts: SafetyNetOptions): SafetyNetHandler;
/**
 * Claim the output stream's `error` event. Returns an uninstall function.
 *
 * This is its sole owner — sinks stay passive readers of the shared
 * broken-stream mark, because claiming the event suppresses Node's fatal-EPIPE
 * exit and a CLI piped into `head` still needs it. Claiming it here is what
 * keeps the failure out of `uncaughtException`, and so out of the log sink
 * that raised it. Install as early as there is a stream to watch: it carries
 * the whole broken-pipe guarantee on its own.
 */
export declare function watchOutputStream(opts: Omit<SafetyNetOptions, "log">): () => void;
/**
 * Register the `uncaughtException` / `unhandledRejection` listeners, which
 * downgrade a stray async error from fatal to logged. Returns an uninstall
 * function; call it when the server shuts down, or an in-process host that
 * starts several servers accumulates listener sets.
 *
 * Install this only once startup has succeeded. Downgrading during boot means
 * a failure before the transport listens no longer stops the process, and it
 * would go on reporting healthy (the process targets check liveness by pid)
 * for a server that never came up.
 */
export declare function installProcessSafetyNet(opts: SafetyNetOptions): () => void;
export {};
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