使用 Rust 全局变量的注意事项

应当区分 static 和 const 关键字的作用, 正如其文档所言:

A static item is a value which is valid for the entire duration of your program (a 'static lifetime).

静态变量是一个在程序的整个生命周期内有效的值 (拥有 'static 的生命周期).

const items look remarkably similar to static items, which introduces some confusion as to which one should be used at which times. To put it simply, constants are inlined wherever they’re used, making using them identical to simply replacing the name of the const with its value. Static variables, on the other hand, point to a single location in memory, which all accesses share. This means that, unlike with constants, they can’t have destructors, and act as a single value across the entire codebase.

const 与 static 看起来非常相似, 可能在使用上引起困惑. 简单来说, 常量在使用的地方都会被内联, 这使得使用它们就像简单地用其值替换 const 的名称一样. 另一方面, 静态变量指向内存中的一个单一位置, 所有访问都共享该位置. 这意味着, 与常量不同, 它们不能有析构函数, 并且在整个代码库中充当一个单一值.

参考资料:

• reddit