[RESOLVED] Error on destruction of boost::shared_ptr

[simps7b2]

I have an stl vector of boost::shared_ptr's declared like so:
vector< shared_ptr<delim_list> > row_data;

delim_list is a custom class encapsulating a vector of strings.

The container is filled like this:
shared_ptr<delim_list> insert_list(new delim_list(line, ','));
row_data.push_back(insert_list);

When the row_data vector goes out of scope there is a access memory reading violation thrown from the std::string library.

I am using VS2005 and am quite at a loss. The code worked when I was using raw pointers, but am now trying to use smart pointers to save time and gain security.

PS: Are there any code tags for these posts?

Thanks,
Ian

[Lindley]

Yes there are code tags.

You probably corrupted an object somewhere with an out-of-bounds write.

I *have* seen a case where a shared pointer to an object containing another shared pointer and so on (basically a linked list) errored on destruction due to stack overflow trying to destroy all the shared_ptrs. But if that isn't your problem then it's probably some form of corruption.

[simps7b2]

Okay,

When you say corruption you mean something perhaps trying to destruct an object twice? Like perhaps the delim_list destructor of the elements of the vector get called before the shared_ptr goes out of scope, or vis-versa.

Just for clarity this is the delim_list classes declaration;

class delim_list
{
private:
	char delimiter;
	vector<string> delim_vec;
	string delim_str;
public:
	delim_list(const string& str, char delim);
	delim_list(vector<string>& vec, char delim);
	delim_list(char delim);
	const string& to_string(){return delim_str;}
	const vector<string>& to_vector(){return delim_vec;}
	void push_back(const string& str);
};

And here is the full code that loads it

//This is a virtual function called from the constructor of CSV_File.
void CSV_File::load_data(ifstream& csv_file)
{
	string line;
	string cell;
        
        //loop through lines in a file and add lines to row_data
	while (getline(csv_file,line))
	{
	    stringstream line_stream(line);
   	    counted_ptr<delim_list> insert_list(new delim_list(line, ','));
	    row_data.push_back(insert_list);
        }
}

So no shared pointer in whats being pointed to. So it must be some sort of corruption. I was a little worried about creating the string 'line' on the stack and then passing it by reference into the constructor for delim_list to create the vector elements, but I think its okay.

[simps7b2]

It looks like I misplaced the location of the error, but its still puzzling. I have a std::auto_ptr to that delim_list class that I declare as a class variable and set during construction. But it is inaccessible after that.

The part of the constructor that sets it looks like this.

//variables line and cell are local to the constructor
string line;
string cell;
getline(csv_file, line);

//load the line into a string stream
stringstream line_stream(line);

header = new delim_list(line, ',');

When I call the to_string method (posted earlier) of the delim_list object referenced by the auto_ptr, I get access memory violations. This same problem causes the code to throw an error when the auto_ptr goes out of scope.