关于STM32CubeMx printf重定向，及报错。"FILE" is undefined

/* USER CODE BEGIN PFP */

#ifdef __GNUC__
/* With GCC, small printf (option LD Linker->Libraries->Small printf
   set to 'Yes') calls __io_putchar() */
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
#else
#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
#endif /* __GNUC__ */

/* USER CODE END PFP */

/* USER CODE BEGIN 0 */
PUTCHAR_PROTOTYPE
{
    HAL_UART_Transmit(&huart1 , (uint8_t *)&ch, 1, 0xFFFF);
    return ch;
}
/* USER CODE END 0 */
 

这样写会报错"FILE" is undefined  添加头文件 stdio.h即可