double free ERR:
容易发生在含有指针的类等于“=”操作之后(几个类的指针成员这是其实指向了同一个地址),当每个类析构函数delete指针的时候其实对同一个地址进行了free,那么就导致double free的错误。
所以类中含有指针成员的时候尽量不要进行类的等于操作。
如果类非得用等于操作,那么就类不能用含有指针成员
/*double free ERR test ,when class operate = ,add by ygx ,2021.05.21*/
class Tool
{
private :
int a{0};
};
class A
{
public:
A()
{
pTool = new Tool();
}
~A()
{
if(pTool)
{
delete pTool;
pTool = NULL;
}
}
private:
Tool * pTool;
};
class Test_copy
{
public:
Test_copy() =default;
void test()
{
cur_A = pre_A;// this time ,cur_A->pTool was set to pre_A->pTool ,they point to the same adress ,so when in A::~A() ,in fact, free the same adress twice, caused double free ERR,
}
private:
A cur_A;
A pre_A;
};
inline void double_free_test()
{
//
Test_copy test1;
test1.test();
}