In contexts where comma is given a special meaning, for example in lists of function arguments and lists of initializers, the required syntactic unit is an assignment expression, so ...

• 这几句话从一个侧面表现出，在某些特定的场合下逗号有特殊含义，比如函数参数列表、初始化列表等等，这时候需要加上一个括号以便区别。例如，