[英]Segmentation fault on using shared_ptr with vectors
如果是我犯了一個非常愚蠢的錯誤並幫助我克服了這種細分錯誤,我將第一次使用shared_ptr。
我希望有一個私有vector
,即使對象被破壞,也可以從不同的類中讀取它。 因此,我讀到有關std::shared_ptr
代碼在storeCounterData
函數中給出了段storeCounterData
在此先感謝您的幫助 !!!
main.cpp
#include <iostream>
#include "counter.hpp"
#include "getCounter.hpp"
const int max_ports = 3;
int main()
{
Counter *counter = new Counter(3);
counter->age = 1;
counter->id = 12;
counter->pincode = 123;
std::vector<Counter*> counterData;
std::cout<<"inside main"<<std::endl;
counter->storeCounterData(counter,0);
counter->storeCounterData(counter,1);
counter->storeCounterData(counter,2);
std::cout<<"inside main calling getCounterData"<<std::endl;
counter->getCounterData(counterData);
Counter countji(3);
countji.getCounterData(counterData);
//getCounterData class function
getCounter *gcount = new getCounter();
gcount->printCounterData();
return 0;
}
Counter.hpp
#ifndef COUNTERHPP
#define COUNTERHPP
#include <vector>
#include <memory>
class Counter
{
private:
typedef std::shared_ptr<Counter> sharedCtr;
std::vector<sharedCtr> vecData;
public:
Counter();
Counter(int vecSize);
int age, id, pincode;
void storeCounterData(Counter *counter,int user);
void getCounterData(std::vector<Counter*> &counter);
};
#endif
Counter.cpp
#include "counter.hpp"
#include <iostream>
#include <vector>
Counter::Counter()
{
}
Counter::Counter(int vecSize):vecData(vecSize)
{
}
void Counter::storeCounterData(Counter *counter,int user)
{
vecData[user]->age = counter->age;
vecData[user]->id = counter->id;
vecData[user]->pincode = counter->pincode;
std::cout<<"vector size inside storeCounterData = "<<vecData.size()<<std::endl;
}
void Counter::getCounterData(std::vector<Counter*> &counter)
{
std::cout<<"vector size inside getCounterData = "<<vecData.size()<<std::endl;
for (auto& c : vecData)
{
std::cout << c->age << std::endl;
std::cout << c->id << std::endl;
std::cout << c->pincode << std::endl;
}
}
輸出量
火箭筒〜/ VECTOR $ ./a.out
內部主要
分段故障(核心已轉儲)
在Counter
的構造方法中,您將創建一個由empty shared_ptr
的向量,即沒有Counter
的托管對象( 請參見此處的(1) )。
只需將行更改為:
Counter(int vecSize) : vecData(vecSize, std::make_shared<Counter>()) {}
編輯:您正在創建一個指針向量,所以我在這里看到兩個選項,您希望它起作用:
shared_ptr
實例化向量,但是每當您訪問指針時,都需要檢查指針是否已經創建。 也許這就是要走的路。 shared_ptr
也是指針,您應該這樣對待它們,並始終檢查其有效性。
Counter(int vecSize) : vecData(vecSize) {} // previous constructor
void storeCounterData(Counter* counter, int user) {
if (!vecData[user]) {
vecData[user] = std::make_shared<Counter>();
}
vecData[user]->age = counter->age;
vecData[user]->id = counter->id;
vecData[user]->pincode = counter->pincode;
std::cout << "vector size inside storeCounterData = " << vecData.size()
<< std::endl;
}
void getCounterData(std::vector<Counter*>& counter) {
std::cout << "vector size inside getCounterData = " << vecData.size()
<< std::endl;
for (auto& c : vecData) {
if (c) {
std::cout << c->age << std::endl;
std::cout << c->id << std::endl;
std::cout << c->pincode << std::endl;
}
}
}
std::vector::push_back
,以便在std::vector::push_back
只有“有效”(您永遠無法確定) shared_ptr
。
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