X programming tutorial

[Jan Stary]

Dear all,

the day has come when I need to do some elementary  programming
(open a window and draw pixels into it). I started with chapter 27
from Stevens: Advanced UNIX Programming, being my favourite author,
but the examples seem to be a bit outdated, at least the manpages
of the X functions describe a slightly different interface.
At any rate, the example below does not open a window.

I am looking at
https://www.x.org/releases/current/doc/libX11/libX11/libX11.html
next, but do people have a favourite X programming intro?

BTW, the manpage for XSetStandardProperties()
doesn't seem to exist on my current/arm64.

        Jan



#include <unistd.h>
#include <stdio.h>
#include <err.h>

#include <X11/Xlib.h>
#include <X11/Xutil.h>

int
main(int argc, char** argv)
{
        Display* display;
        XSizeHints hints;
        Window window;

        int screen;
        unsigned long white;
        unsigned long black;

        if ((display = XOpenDisplay(NULL)) == NULL) {
                /* err() is not usefull here, these are not system errors.
                 * Does X11 have any arror reporting framework? */
                errx(1, "Error getting Display");
        }

        screen = DefaultScreen(display);
        white = WhitePixel(display, screen);
        black = BlackPixel(display, screen);

        hints.x = 300;
        hints.y = 500;
        hints.width = 200;
        hints.height = 100;
        hints.flags = PPosition | PSize;

        window = XCreateSimpleWindow(display, DefaultRootWindow(display),
                hints.x, hints.y, hints.width, hints.height, 10, white, black);

        XSetStandardProperties(display, window, "wname", "iname", None,
                NULL, 0, &hints);

        /*XMapWindow(display, window);*/
        XMapRaised(display, window);

        while (1) {
                sleep(1);
        }

        XDestroyWindow(display, window);
        XCloseDisplay(display);

        return 0;
}