segfault on XSelectInput

x11.c

#include <X11/Xlib.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <math.h>

#define NANOSECONDS_MULTIPLIER 1000000

void run(Display *display, Window *window, XEvent *event, int *screen);

const long interval = 500 * NANOSECONDS_MULTIPLIER;
int frame = 0;

typedef struct Engine {
	Display *display;
	Window window;
	XEvent event;
	int screen;
} Engine;

int main(int argc, char** argv, char** env) {

    // Initialization
    Engine *engine = calloc(1, sizeof(Engine));
    engine->display = XOpenDisplay(NULL);
    if (engine->display == NULL) {
        fprintf(stderr, "Cannot open display\n");
        exit(1);
    }
    engine->screen = XDefaultScreen(engine->display);
    engine->window = XRootWindow(engine->display, 0);

    XSelectInput(engine->display, engine->window, KeyReleaseMask | KeyPressMask);

    run(engine->display, (Window *) engine->window, &engine->event, &engine->screen);

    XCloseDisplay(engine->display);
    free(engine);
    return 0;
}

void run(Display *display, Window *window, XEvent *event, int *screen) {
    while(event->type != KeyPress) {
	double x = 1000 * cos(frame);
	double y = 1000 * sin(frame);
        XWarpPointer(display, None, *window, 0, 0, 0, 0, x, y);

        if (frame > XDisplayWidth(display, *screen))
            frame = 0;

        frame++;
	fprintf(stdout, "Running! -- frame: %d\n", frame);

	nanosleep((const struct timespec[]){{0, interval}}, NULL);

        XFlush(display);
    }
}