会员字段，施工顺序 [英] Member fields, order of construction

问题描述

在C ++中，当执行类似下面所示的操作时，结构的顺序是否得到保证？

In C++, when doing something like what you see below, is the order of construction guaranteed?

Logger::Logger()
    : kFilePath_("../logs/runtime.log"), logFile_(kFilePath_)
{
    // ...
}

推荐答案

是的，施工的顺序总是得到保证。但是，它并不保证与对象在初始化器列表中出现的顺序相同。

Yes, the order of construction is always guaranteed. It is not, however, guaranteed to be the same as the order in which the objects appear in the initializer list.

成员变量按照它们的顺序构造在类的正文中声明。例如：

Member variables are constructed in the order in which they are declared in the body of the class. For example:

struct A { };
struct B { };

struct S {
    A a;
    B b;

    S() : b(), a() { }
};

首先构建 c $ c> b 。成员变量在初始化程序列表中显示的顺序与此无关。

a is constructed first, then b. The order in which member variables appear in the initializer list is irrelevant.

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