我的代码包含两个类。
class points{
char *p;
public: points(){cout<<"constructor points called"<<endl;p=new char();}
virtual ~points(){cout<<"destructor points called"<<endl;delete(p);}
};
class otherpoints: public points{
points x1;
public: otherpoints(){cout<<"constructor otherpoints called"<<endl;x1=points();}
~otherpoints(){cout<<"destructor otherpoints called"<<endl;}
};
int main(int argc, char *argv[])
{
otherpoints y1;
return 0;
}
这里我在基类构造函数中分配了一个指针,并在各自的基类析构函数中销毁了指针的内存。
当我使用 valgrind 运行二进制文件时,出现错误:-
constructor points called
constructor points called
constructor otherpoints called
constructor points called
destructor points called
destructor otherpoints called
destructor points called
==2209== Invalid free() / delete / delete[]
==2209== at 0x4024851: operator delete(void*) (vg_replace_malloc.c:387)
==2209== by 0x8048A36: points::~points() (in home/santosh/programs/c++/parent_child_conscall)
==2209== by 0x8048BB2: otherpoints::~otherpoints() (in /home/santosh/programs/c++/parent_child_conscall)
==2209== by 0x804889A: main (in /home/santosh/programs/c++/parent_child_conscall)
==2209== Address 0x42d5098 is 0 bytes inside a block of size 1 free'd
==2209== at 0x4024851: operator delete(void*) (vg_replace_malloc.c:387)
==2209== by 0x8048A36: points::~points() (in /home/santosh/programs/c++/parent_child_conscall)
==2209== by 0x8048B32: otherpoints::otherpoints() (in /home/santosh/programs/c++/parent_child_conscall)
==2209== by 0x8048889: main (in /home/santosh/programs/c++/parent_child_conscall)
==2209== destructor points called
==2209==
==2209== HEAP SUMMARY:
==2209== in use at exit: 1 bytes in 1 blocks
==2209== total heap usage: 3 allocs, 3 frees, 3 bytes allocated
==2209==
==2209== LEAK SUMMARY:
==2209== definitely lost: 1 bytes in 1 blocks
==2209== indirectly lost: 0 bytes in 0 blocks
==2209== possibly lost: 0 bytes in 0 blocks
==2209== still reachable: 0 bytes in 0 blocks
==2209== suppressed: 0 bytes in 0 blocks
==2209== Rerun with --leak-check=full to see details of leaked memory
==2209==
==2209== For counts of detected and suppressed errors, rerun with: -v
==2209== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 18 from 7)
无法知道我无法释放哪个 1 字节内存。
我必须发布回溯报告吗?
感谢任何帮助。
最佳答案
这里的问题是您创建了 points
类的两个实例。一个带有 points()
的临时值,当然还有一个带有 x1
的声明。
当您执行 x1 = points()
时,您使用 points()
构造创建一个临时对象,然后将其复制分配给 x1
,然后临时对象被销毁。由于您没有提供复制赋值运算符,编译器将为您创建一个,但它只是复制指针,而不分配新内存。这意味着你有一段时间有两个包含指向同一内存的指针的对象。当临时对象被销毁时,您释放析构函数中的内存,使 x1
中的指针悬空。当 x1
被销毁时,您尝试删除这个悬挂指针,导致双重释放错误。
解决此问题的最佳方法是实现复制赋值运算符,最好是复制构造函数,并在其中分配新内存并复制数据。
关于c++ - *** 检测到 glibc *** ./parent_child_conscall : double free or corruption (fasttop): 0x09d9e028 ***,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/18465048/