C语言：Expression with side effects passed to repeated parameter

编译中遇到Expression with side effects passed to repeated parameter 1 in macro的警告。具体原因是：宏定义中变量替代之后，变量可能多次计算，https://stackoverflow.com/questions/32284073/what-are-expressions-with-side-effects-and-why-should-they-be-not-passed-to-a-ma