list/vector iterator not incrementable - c++

Question

So I have an issue trying to iterate through my container in c++ with visual studio Community 2015.
I'm trying to write a server/client on windows using select() and I get the error:
vector iterator not incrementable
I'm not calling a vector::erase() or such, although I do use a vector::push_back()
void MGKServer::mainLoop()
{
MGKServerSocket *mgk;
std::vector<User *> users;
int actual = 0;
char buffer[1024];
mgk = new WindowsServerSocket();
mgk->init("127.0.0.1", 4242, "TCP");
int sock = mgk->getSock();
std::cout << "sock is: " << mgk->getSock() << std::endl;
while (1)
{
this->setFd(sock, &users); // FD_ZERO(&_readfd) and FD_SET for each user's socket and the server socket
std::cout << "there is currently " << users.size() << " user(s) connected" << std::endl;
if (select(FD_SETSIZE + 1, &this->_readfd, NULL, NULL, NULL) == -1)
exit(errno);
// When a user connects
if (FD_ISSET(sock, &this->_readfd))
{
// addNewUser creates a pointer to an object User , set his socket to the given one and push it in the vector
if (this->addNewUser(sock, &users) == -1)
std::cout << "Can't add newUser" << std::endl;
}
// When a user sends a message to the server
else
{
int debug = 0;
std::vector<User *>::iterator it = users.begin();
while (it != users.end())
{
if (it == users.end())
std::cout << "Test if something went wrong with iterations" << std::endl;
if (FD_ISSET((*it)->getSocket(), &this->_readfd))
{
// RecvUser will just call recv with the client socket and store the message in buffer.
int c = mgk->recvUser((*it)->getSocket(), buffer);
// Means the user disconnected so i close his socket
if (c == 0)
{
std::cout << "user with socket: " << (*it)->getSocket() << "disconnected" << std::endl;
closesocket((*it)->getSocket());
}
// Means he sends an instruction
else
std::cout << "ok" << std::endl;
}
std::cout << "Debug = " << debug << std::endl;
++debug;
it++; // <- This small line seems to be the problem
}
std::cout << "Out of For loop" << std::endl;
}
std::cout << "found something on socket" << std::endl;
}
}
here is what i do in addNewUser:
int MGKServer::addNewUser(int socket, std::vector<User *> *users)
{
std::cout << "----NEW USER----" << std::endl;
SOCKADDR_IN usin = { 0 };
User *u;
int size;
int usock;
size = sizeof(usin);
std::cout << "New user is trying to connect, socket is: ";
usock = accept(socket, (SOCKADDR *)&usin, &size);
if (usock == SOCKET_ERROR)
{
std::cout << "socket error occured" << std::endl;
return (-1);
}
std::cout << usock << std::endl;
FD_SET(usock, &this->_readfd);
u = new User();
u->setSocket(usock);
users->push_back(u);
return (0);
}
My object User only contains a socket with get&set methods for now.
My MGKServerSocket is just an abstration for windows/linux socket. It contain basic function for initializing my socket and send & recv data to users.
So at first I had a list container but I've got the same error. So I switched to try with vector instead but nothing changed.
In the beginning, I also used a for loop instead of my current while loop but, once again, nothing changed.
I know that there's already many questions for this error, but they usually use erase, insert inside the for loop or create the iterator when the list is empty which I don't. So my question is, why do I get this error ?