import tty from 'tty';
/** The current keyboard stream (process.stdin by default). */
export declare const keyboard: () => tty.ReadStream;
/** The keyboard's file descriptor, for synchronous interrupt polls. */
export declare const keyboardFd: () => number;
export declare function openTtyKeyboard(): boolean;
/** A never-blocking tty fd for mid-scan interrupt polls, or null
 *  when the platform has no pollable terminal device. */
export declare function keyboardPollFd(): number | null;
/**
 * True when the terminal lacks cursor capabilities, like less's
 * missing_cap: on unix a missing $TERM loads the "unknown" termcap
 * entry (screen.c's DEFAULT_TERM), which turns up dumb. less's Windows
 * build never consults $TERM — it drives the console API directly —
 * so a Windows console only degrades when it predates the VT
 * processing that node enables on its tty streams (Windows 10 build
 * 10586), or when $TERM names dumb explicitly.
 */
export declare function dumbTerminal(): boolean;
/** Queues a polled key for after the blocking read (ungetcc_back). */
export declare function pushUngot(data: Buffer): void;
/** Queues a key that was typed with the current screen already up. */
export declare function pushUngotLive(data: Buffer): void;
/** Whether the queue holds a key typed against the current screen. */
export declare const ungotIsLive: () => boolean;
/** Takes all queued keys, oldest first; null when none wait. */
export declare function takeUngot(): Buffer | null;
/** less's ABORT_SIGS(). */
export declare const abortSigs: () => boolean;
/** less's `sigs |= S_INTERRUPT`, from wherever the ^C was noticed. */
export declare function raiseAbort(): void;
/** less's psignals clearing the flag once it has been handled. */
export declare function clearAbort(): void;
/**
 * Discards the queued keys, like less's iread on READ_INTR running
 * `getcc_clear()` (os.c): keys typed before the interrupt — the
 * aborting ^C included — never run as commands. Keys still unread
 * in the kernel's tty buffer survive, exactly like less's.
 */
export declare function consumeInterrupt(): void;
/** True while ungot input pends, less's prompt() early-return test. */
export declare function hasUngot(): boolean;
/**
 * less's error()/get_return inline gate: prints the message on the
 * prompt line, BLOCKS for one raw key (output.c:696 - RETURN, space
 * or an interrupt dismiss; any other key ungets to run as the next
 * command), then clears the line so the interrupted action continues.
 */
type GateRelease = 'dismiss' | 'unget' | 'winch';
/** The last gate's release kind. */
export declare function gateReleaseKind(): GateRelease;
/** Reads whether the last gate was released by a resize. */
export declare function gateReleasedByWinch(): boolean;
/** The column the last gate's message reached. */
export declare function gateEndColumn(): number;
export declare function gateReturn(message: string): void;
/** Emulates ISIG for a typed ^C: SIGINT to our process group. */
export declare function raiseSigint(): void;
/** Consumes the self-signal mark: true when the SIGINT now being
 *  handled came from raiseSigint (the ^C byte path already acted). */
export declare function wasSelfSigint(): boolean;
/**
 * The terminal size straight from the kernel, like less's scrsize
 * ioctl: node caches the winsize and refreshes it only in its own
 * SIGWINCH processing — a blocking scan delays that past less's
 * update_term moment, and a raw SIGWINCH handler can run before
 * the refresh. Returns [columns, rows], falling back to node's
 * cache when stty is unavailable (Windows).
 */
export declare function freshWindowSize(): [number, number] | null;
/**
 * Watches window changes like less's lwinch: the handler fires on the
 * SIGNAL itself — less's psignals runs screen_trashed() even when the
 * size did not change, and the longjmp dismisses get_return waits —
 * while node's 'resize' event only fires when the dimensions
 * differ. Windows has no SIGWINCH, so 'resize' covers it, like less
 * polling the console size.
 */
export declare function watchWinch(fn: () => void): void;
/** Removes a watchWinch handler. */
export declare function unwatchWinch(fn: () => void): void;
/**
 * Releases a /dev/tty keyboard, like close_getchr: the open tty
 * handle would otherwise keep the process alive after the pager
 * quits.
 */
export declare function closeTtyKeyboard(): void;
export {};