In one of my project I managed to fix a bug switching from a std::vector of objects to a std::vector of pointers to the object. Using the debugger I found that the error occurred when I was calling the std::vector<T,Allocator>::clear that it is supposed to destroy the objects stored in the vector. I am happy I solved the issue but I would like to know why I was able to! Here I attach the code incriminated:
#include <vector>
#include <memory>
#include <string>
class Base
{
public:
Base(int a);
Base(const Base& o)=default;
Base& operator=(const Base& o)=default;
Base(Base&& o)=default;
Base& operator=(Base&& o)=default;
virtual ~Base()=default;
virtual void Do();
};
class Derived: public Base
{
private:
std::string b;
public:
Derived(int a, std::string& b) : Base(a), b(b) {}
};
//Other derived classes from Base overriding Do
class Main{
private:
std::vector<Derived> v;
public:
Main();
void Do(int i, std::string& b){
/*
if something happens
v.emplace_back(a, b);// push_back equivalently for our purpose
if something else happens
v.erase(iterator)
*/
}
void reset(){
v.clear();
}
};
class Main1{
private:
std::vector<std::unique_ptr<Derived>> v;
public:
Main1();
void Do(int i, std::string& b){
/*
if something happens
v.push_back(std::unique_ptr<Derived>(new Derived(i, b)));
if something else happens
v.erase(iterator)
*/
}
void reset(){
v.clear();
}
};
int main()
{
Main m;
for(int i=0; i<101; ++i){
//something
m.Do(i, b);
//something
if(i%10==0)
m.reset(); //The bug is here. If I use Main1 everything runs smoothly
}
return 0;
}
This is a simplified version of the code that creates me problem. I hope that the detail are enough to give the correct contest for the answer. The debugger points me deep in the code defining what a deconstructor does reporting a segmentation fault, and personally I cannot understand what that code does. The compiler I am using is g++ 10.1 with the std=c++17 flag.
