/**
 * base class for all known argv errors.
 *  - ideally, argv will only throw errors that are subclasses of this.
 */
export declare class ArgvError extends Error {
    constructor(message: string);
}
/** developer error configuring argv. */
export declare class ConfigError extends ArgvError {
    constructor(message: string);
}
/** user error in supplying command line inputs. */
export declare class MistakeError extends ArgvError {
    constructor(message: string);
}
/** devs should throw this error in an `execute` function, if they want argv to pretty-print the error. */
export declare class ExecutionError extends ArgvError {
}
/** happens when user-provided onExit doesn't actually end the process (also useful in testing). */
export declare class ExitFail extends ArgvError {
}