def _init():#初始化
    global _globalDict
    _globalDict = {}
    _globalDict['ModBusTcp'] = 0
    _globalDict['ModBusRtu'] = 1
    _globalDict['currentPro'] = -1     # 当前工程名
    _globalDict['currentProDB'] = 0   # 当前工程的数据库连接
    _globalDict['varTable'] = 0       # 变量表
    _globalDict['userTable'] = 0      # 用户表
    _globalDict['popen'] = 0          # 通讯进程
    _globalDict['beatPopen'] = 0      # 通讯定时进程
    _globalDict['forceVars'] = set()
    _globalDict['currentProType'] = -1 # 当前工程类型   0 : MODBUSTCP 主站模式
    _globalDict['SearchWidget'] = 0                  # 1 : MODBUSTCP 从站模式
                                                    # 2 : MODBUSRTU 主站模式
                                                    # 3 : MODBUSRTU 从站模式
    _globalDict['FFThread'] = 0
    _globalDict['RTDTCThread'] = 0
    _globalDict['AnalogThread'] = 0
    _globalDict['FFSimulateThread'] = 0
    _globalDict['HartSimulateThread'] = 0
    _globalDict['HistoryWidget'] = 0
    _globalDict['projectNumber'] = None
    _globalDict['username'] = None
    _globalDict['MainWindow'] = None
def setValue(key,value):
    """ 定义一个全局变量 """
    _globalDict[key] = value

def getValue(key,defValue=None):
    """ 获得一个全局变量,不存在则返回默认值 """
    try:
        return _globalDict[key]
    except KeyError:
        print('没有这个变量')
        return False
def clearValue(key):
    _globalDict[key].clear()