We then use the def macro to define a constant called big-num-str.

之后，使用def宏来定义一个常量，称为big - num - str。

youdao

Otherwise, if the expression is not a constant, another macro function is called to round up the value to a power of two.

如果表达式不是常量，就调用另一个宏函数把值向上取整到2的幂。

youdao

If you do not define this macro, the usual case, GCC will output the constant pool before the function.

如果没有定义这个宏，在通常情况下，GCC会在函数之前输出。

youdao