如何推迟shared_ptr的删除操作? [英] how to defer delete operation of shared_ptr?

问题描述

我在main中创建了sample类的指针.我正在将此指针传递给函数function1().该函数必须使用指针作为共享指针，并使用该指针执行一些操作.在function1()退出期间，由于shared_ptr而调用了sample的析构函数.当我将相同的指针传递给不同的函数时，该指针不再有效，并且程序崩溃.

I have created a pointer of sample class in main. I am passing this pointer to a function function1(). This function has to use pointer as shared pointer and do some operations using this pointer. During exit of function1() destructor of sample in invoked due to shared_ptr. When I pass the same pointer to different function, this pointer is no more valid and program crashes.

1.如何延迟function1()中的删除操作(销毁调用)?

1.How do I defer delete operation ( destruction invocation) in function1()?

2.另一种方法是什么，以便我可以将指针传递给不同的函数并安全地使用它，尽管某些函数将指针用作shared_ptr?

2.What is the alternative way, so that I can pass pointer to different functions and use it safely, though some of the function are using pointer as shared_ptr?

这里有示例代码和输出.

Here I have sample code and output.

#include <memory>
#include <iostream>
#include <string.h>

using namespace std;

class sample
{
    private:
        char * data;

    public:
        sample( char * data )
        { 
            cout << __FUNCTION__ << endl;
            this->data = new char[strlen( data)];
            strcpy( this->data, data ); 

        }
        ~sample()
        {
            cout << __FUNCTION__ << endl; 
            delete this->data; 
        }
        void print_data()
        { 
            cout << __FUNCTION__ << endl;
            cout << "data = " << this->data << endl;
        }
};

void function1( sample * ptr )
{
    shared_ptr<sample> samp( ptr );
    /* do something with samp */
    ptr->print_data();
}

void function2( sample * ptr )
{
    ptr->print_data();
}

int main()
{
    char data[10] = "123456789";
    data[10] = '\0';
    sample * s = new sample( data );

    function1( s );
    function2( s );

    return 0;
}

输出:

sample
print_data
data = 123456789
~sample
print_data
data = 

推荐答案

更改

sample * s = new sample( data );

进入

shared_ptr<sample> s(new sample( data ));

，并将共享的Poiter传递给所有函数.当此变量超出范围时，它将被删除，因此为您的目的已经足够晚了

and pass the shared poiter to all functions. It will be deleted when this variable gets out of scope, so late enough for your purposes

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