实例方法中的静态变量 [英] Static variables in instance methods

问题描述

假设我有这个程式：

class Foo {
 public:
    unsigned int bar () {
        static unsigned int counter = 0;
        return counter++;
    }
};

int main ()
{
    Foo a;
    Foo b;
}

（当然这个例子没有意义，因为我明显声明counter 作为私有属性，但它只是为了说明问题）。

(Of course this example makes no sense since I'd obviously declare "counter" as a private attribute, but it's just to illustrate the problem).

我想知道C ++在这种情况下的行为：将变量counter

I'd like to know how C++ behaves in this kind of situation: will the variable "counter" in the bar() method be the same for every instance?

推荐答案

是， code>将在您的可执行文件中的 Foo 类型的所有实例之间共享。

Yes, counter will be shared across all instances of objects of type Foo in your executable. As long as you're in a singlethreaded environment, it'll work as expected as a shared counter.

在多线程环境中，你会有一些有趣的竞态条件， debug：）。

In a multithreaded environment, you'll have interesting race conditions to debug :).

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