Evaluating vector::empty() is crashing the program - c++

Question

I'm currently writing an extension of another program (Specificly, of a game) and i've been stuck on solving the following problem for hours now.
Any time a player (client) connects to the game server, the OnClientConnected(int client_number); function is called. In this function, i create an instance of a CPlayer class that stores player information, such as health, speed and any other data i might require. This instance, is then stored by the following class:
class CPlayerManager
{
std::vector<Player*> *player_list;
public:
CPlayerManager();
~CPlayerManager();
void AddPlayer(client_id)
*CPlayer GetPlayerInstance(client_id);
}
CPlayerManager()
{
player_list = new std::vector<Player*>;
}
~CPlayerManager()
{
delete player_list;
}
void CPlayerManager::AddPlayer(client_id)
{
CPlayer *player = new CPlayer(client_id);
player_list->push_back(player);
}
void *CPlayerManager::GetPlayerInstance(client_id)
{
if(player_list->empty())
{
return NULL;
}
for(std::vector<CPlayer*>::size_type i = 0; i != player_list->size(); i++)
{
int client = player_list->at(i)->GetClientId();
if(client_id == client)
{
return player_list->at(i);
}
}
return NULL;
}
Original game functions use a client indexes as arguments and return values, so i need to obtain player instances from client indexes all the time. The problem is in the GetPlayerInstance function. This function might be called when NO client has been yet initialized and stored by the CPlayerManager instance, so we might have an empty vector.
Anytime the GetPlayerInstance function is called when the vector is empty, the entire game server crashes. I've been debugging a bit, and i noticed that the program crashes right in:
//Code reaches here
if(player_list->empty())
{
//code does not reach here
return NULL;
}
Doing bool empty = player_list->empty()) works until i evaluate empty on the if statement.
What could be causing this strange crash?

Answer 1

Your CPlayerManager class has no copy assignment operator or copy constructor. So if you ever copy it, deleting one instance will delete the other instance's vector, leading to disaster. (Follow the rule of three.)
Really, this code should be nuked from orbit. You have no need for a pointer to a vector nor do you need a vector of pointers. Both of these things are just asking for trouble.