STM32F4 UCOSIII 外部中断配置问题

在 UCOSIII 再配置 GPIOC Pin13 为外部中断口

EXTI_InitTypeDef EXTI_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);  // SYSCFG
//GPIOC.13  
SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource13); //PC13  
EXTI_InitStructure.EXTI_Line=EXTI_Line13;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  
EXTI_Init(&EXTI_InitStructure);

编译时报 ..OBJTemplate.axf: Error: L6218E: Undefined symbol EXTI_Init (referred from usart.o).

请指教  UCOSIII下 如何配置GPIO外部中断，谢谢！！！