在代码中添加异常处理程序来捕获抛出的异常并防止程序失败。以下是一个示例：

import time
import subprocess
import re
import sys

import locale
locale.setlocale(locale.LC_ALL, '')

from Xlib import display, X
from Xlib.protocol import request

TITLE_RE = re.compile(b'^_NET_WM_NAME|^WM_NAME')

def get_active_window():
    root = display.Display().screen().root
    window_id = root.get_full_property(display.Display().intern_atom('_NET_ACTIVE_WINDOW').id, X.AnyPropertyType).value[0]
    window = None
    try:
        window = root.create_resource_object('window', window_id)
        title = None
        for attempt in range(100):
            title = get_window_title(window)
            if title == None:
                time.sleep(0.001)
            else:
                break
    finally:
        return title

def get_window_title(window):
    try:
        for atom in map(display.Display().intern_atom,('_NET_WM_NAME', 'WM_NAME')):
            reply = request.GetProperty(
                window,
                atom,
                request.GetProperty.dont_delete,
                0,
                2**32-1).reply()
            if reply and reply.type == Xlib.X.STRING:
                return reply.value
        return None
    except:
        return None

try:
    active_window_title = get_active_window().decode(locale.getpreferredencoding())
except Exception as e:
    active_window_title = ""

#异常处理
if active_window_title == "":
    active_window_title = "Error: " + str(e)

在这个示例中，当 get_active_window() 函数返回空时，程序会在标题中添加一条错误消息。