#include <X11/Xlib.h>

int main()

{

    Display * dsp = XOpenDisplay(NULL);

    int screenNum = DefaultScreen(dsp);

    unsigned long white = WhitePixel(dsp, screenNum);

    unsigned long black = BlackPixel(dsp, screenNum);

    Window win = XCreateSimpleWindow(dsp, DefaultRootWindow(dsp), 0, 0, 1024, 800, 0, black, white);

    XSelectInput(dsp, win, ExposureMask | KeyPressMask);

    GC gc = XCreateGC(dsp, win, 0, NULL);

    XMapWindow(dsp, win);

    XFlush(dsp);

    XEvent event;

    do

    {

        XNextEvent(dsp, &event);

        switch (event.type)

        {

            case Expose:

            for (int i = 0; i < 300; ++i)

            {

                XDrawPoint(dsp, win, gc, 400+i, 400);

            }

            break;

        default:

            break;

        }

    } while (event.type != MapNotify);

    return 0;

}