类对象和动态内存分配的 C++ 向量 [英] C++ vector of class objects and dynamic memory allocation
问题描述
这是我想要做的简化版本,它在调用 push_back 时崩溃,特别是在调用析构函数时.如果我删除析构函数的主体,它可以工作,但我想确保它被删除.我尝试使用 new/delete 代替 calloc/free,结果相同.我在这里做错了什么?
This is a simplified version of what I want to do, it crushes when push_back is called, specifically when the destructor is called. If I delete the body of the destructor it works, but I want to be sure that it is deleted. Instead of calloc/free I tried new/delete with the same result. What do I do wrong here?
#include <cstdlib>
#include <vector>
using namespace std;
class Buffer
{
public:
float *DATA;
Buffer(int length) {DATA = (float*) calloc (length,sizeof(float));};
virtual ~Buffer(){free (DATA);};
private:
};
int main(int argc, char** argv)
{
vector <Buffer> v;
for (int i =0; i<10; i++)
v.push_back(Buffer(1000));
return 0;
}
推荐答案
这是一个工作代码:https://Godbolt.org/z/ex9oMG.
#include <cstdlib>
#include <vector>
using namespace std;
class Buffer
{
public:
float *DATA;
Buffer(int length) {DATA = (float*) calloc (length,sizeof(float));};
Buffer(const Buffer &buffer) = delete;
Buffer(Buffer&& buffer) {
DATA = buffer.DATA;
buffer.DATA = nullptr;
}
~Buffer(){
if (DATA) free(DATA);
};
private:
};
int main(int argc, char** argv)
{
vector <Buffer> v;
for (int i =0; i<10; i++)
v.push_back(Buffer(1000));
return 0;
}
你需要在这里定义一个移动构造函数,主要是因为v.push_back(Buffer(1000))
需要一个移动操作,否则删除原始副本会释放资源.
You need to define a move constructor here, primarily because v.push_back(Buffer(1000))
requires a move op otherwise the deletion of the original copy would free the resource.
我已经明确删除了复制构造函数,因为在处理此类资源时 - 不应允许复制.
I've explicitly deleted the copy ctor because when handling such resources - copy should not be allowed.
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