C++对象创建引起的奇怪分段错误

发布于 2024-09-30 14:51:04 字数 833 浏览 6 评论 0原文

我通过启动类对象遇到了一个奇怪的问题。这个问题既奇怪又不容易重现。不过我会尝试举一个有代表性的例子。我有继承类。

class BarClass {
public:
   BarClass() {
      ...
   }
   BarClass(int i, int j) {
      ...
   }
   void doSomething() { ... }
};
class FooClass : public BarClass {
public:
   FooClass() {
   }
   FooClass(int i, int j) : BarClass(i,j) {
      ...
   }
};

有时，如果我用以下方式启动对象，我会通过初始化得到分段错误错误。

FooClass foo1;
foo1.doSomething();
FooClass foo2(10, 20);
foo2.doSomething();

如果我使用显式指针 new，那么就可以了。

FooClass *foo1= new FooClass();
foo1->doSomething();
FooClass foo2(10, 20);
foo2.doSomething();

以下代码将在第 2 行给我一个编译器错误

FooClass foo1();
foo1.doSomething();
FooClass foo2(10, 20);
foo2.doSomething();

。我应该如何正确启动一个对象，特别是当它具有默认构造函数和带有参数的构造函数时。

原文

I have a strange problem by initiating a class object.
The problem is as strange as well not easily reproducible. However I will try to give an indicating example.
I have inheritance classes.

class BarClass {
public:
   BarClass() {
      ...
   }
   BarClass(int i, int j) {
      ...
   }
   void doSomething() { ... }
};
class FooClass : public BarClass {
public:
   FooClass() {
   }
   FooClass(int i, int j) : BarClass(i,j) {
      ...
   }
};

Sometime if I initiate objects with following manner, I will get segmentation fault error by initialization.

FooClass foo1;
foo1.doSomething();
FooClass foo2(10, 20);
foo2.doSomething();

If I use explicit pointer new, then it is OK..

FooClass *foo1= new FooClass();
foo1->doSomething();
FooClass foo2(10, 20);
foo2.doSomething();

The following code will give me a compiler error on line 2.

FooClass foo1();
foo1.doSomething();
FooClass foo2(10, 20);
foo2.doSomething();

how should I properly initiate a object, especially when it has default constructor and those with arguments.

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冷血 2024-10-07 14:51:04

首先，您的最后一个问题...

FooClass foo1();

不会创建 FooClass 类型的对象，而是声明一个名为 foo1() 的函数，该函数不带任何参数并返回 FooClass。删除括号以创建实例，就像在第一个代码示例中所做的那样。

为什么出现分段错误可能与我们看不到的析构函数有关，并且在第二个泄漏的示例中不会调用它。

Your last issue first...

FooClass foo1();

does not create an object of type FooClass but declares a function called foo1() that takes no parameters and returns a FooClass. Remove the parentheses to create the instance as you did in the first code sample.

why you get a segmmentation fault may have something to do with your destructor which we can't see, and this doesn't get invoked in your second example which leaks.

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