Unreliable errors while multithreading in SFML for C++ - c++

Question

I am trying to make a basic game in c++ using the SFML library. For this game, I want a thread
drawing at a fixed rate and another thread checking for input as often as possible. The first problem I encountered was that the SFML library does not allow for window to be active on multiple threads. A simple fix for this was found by just deactivating the window in the main thread. The next problem that I have not yet found a fix for is that I cannot seem to check for input on my main thread (In this scenario).
This code is very unreliable. I can get two different error messages, or an infinite loop. What should happen is an infinite loop that can be closed with the escape key, and if you press d it prints a message.
The library I am using is libsfml-dev
My compile arguments are as follows: g++ test.cpp -pthread -lsfml-graphics -lsfml-window -lsfml-system
#include <iostream>
#include <stdio.h>
#include <pthread.h>
#include <SFML/Graphics.hpp>
#include <SFML/System.hpp>
sf::RenderWindow window(sf::VideoMode(800, 800), "");
using namespace std;
void *func(void *threadid) {
cout << "New thread." << endl;
while (window.isOpen()) {
// In the actual implementation, this would be replaced with draw methods
if (sf::Keyboard::isKeyPressed(sf::Keyboard::Escape)) {
window.close();
}
}
pthread_exit(NULL);
}
int main() {
// Needed so that window is only active on a single thread
window.setActive(false);
// Create new thread
pthread_t threads[1];
int val;
val = pthread_create(&threads[0], NULL, func, (void *)1);
cout << "Main thread." << endl;
while (window.isOpen()) {
if (sf::Keyboard::isKeyPressed(sf::Keyboard::D)) {
cout << "D button pressed." << endl;
}
}
return 0;
}
Error Number 1
PS: XInitThreads doesn't help
Error Number 2
Looks like an error from my X server