x11 invisible window (for my i3 persistent workspace dirty workaround)

xcb-invis.cpp

#include <xcb/xcb.h>
#include <xcb/xcb_ewmh.h>

#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <cstdlib>

#define PROGRAM "xcb-invis"

int main(int argc, char *argv[]) {

	if (argv[1] == nullptr) {
		fprintf(stderr, "usage: %s <WM_NAME>", PROGRAM);
		return 2;
	}

	xcb_connection_t *connection = xcb_connect(NULL, NULL);

	const xcb_setup_t *setup = xcb_get_setup(connection);
	xcb_screen_t *screen = xcb_setup_roots_iterator(setup).data;
	
	xcb_ewmh_connection_t ewmh;
	xcb_intern_atom_cookie_t *ewmh_cookie = xcb_ewmh_init_atoms(connection, &ewmh);

	xcb_depth_iterator_t depth_iter = xcb_screen_allowed_depths_iterator(screen);
	xcb_depth_t *depth = NULL;

	for (; depth_iter.rem; xcb_depth_next(&depth_iter)) {
		/* printf("%i\n", depth_iter.data->depth); */
		if (depth_iter.data->depth == 32 && depth_iter.data->visuals_len) {
			depth = depth_iter.data;
			break;
		}
	}

	xcb_visualtype_iterator_t visual_iter = xcb_depth_visuals_iterator(depth);
	xcb_visualtype_t *visual = NULL;

	for (; visual_iter.rem; xcb_visualtype_next(&visual_iter)) {
		if (visual_iter.data->_class == XCB_VISUAL_CLASS_TRUE_COLOR) {
			visual = visual_iter.data;
			break;
		}
	}

	xcb_colormap_t colormapId = xcb_generate_id (connection);
	xcb_create_colormap (connection,
					 XCB_COLORMAP_ALLOC_NONE,
					 colormapId,
					 screen->root,
					 visual->visual_id );


	unsigned int cw_mask = XCB_CW_BACK_PIXEL | XCB_CW_BORDER_PIXEL | XCB_CW_COLORMAP;
	unsigned int cw_values[] = { 0x00000000, 0, colormapId };

	xcb_window_t window = xcb_generate_id(connection);
	auto cookie = xcb_create_window_checked(
		connection,
		depth->depth,
		window,
		screen->root,
		screen->width_in_pixels - 1, screen->height_in_pixels - 1,
		1, 1,
		0,
		XCB_WINDOW_CLASS_INPUT_OUTPUT,
		visual->visual_id,
		cw_mask,
		cw_values);

	auto error = xcb_request_check(connection, cookie);
	if (error) {
		fprintf(stderr, "ERROR: failed to create window: %i\n", error->error_code);
		xcb_disconnect(connection);
		return -1;
	}

	if (xcb_ewmh_init_atoms_replies(&ewmh, ewmh_cookie, NULL)) {
		xcb_change_property(connection, XCB_PROP_MODE_REPLACE, window, ewmh._NET_WM_STATE, XCB_ATOM_ATOM, 32, 1, &(ewmh._NET_WM_STATE_SKIP_TASKBAR));
	}

	size_t len = strlen(PROGRAM) + strlen(argv[1]) + 2;
	char* window_class = static_cast<char*>(malloc(len));

	if (window_class == NULL) {
		abort();
	}

	memcpy(window_class, argv[1], strlen(argv[1]) + 1);
	memcpy(window_class + strlen(argv[1]) + 1, PROGRAM, strlen(PROGRAM) + 1);

	xcb_change_property (connection, XCB_PROP_MODE_REPLACE, window,
		XCB_ATOM_WM_CLASS, XCB_ATOM_STRING, 8,
		len, window_class);

	xcb_change_property (connection, XCB_PROP_MODE_REPLACE, window,
		XCB_ATOM_WM_NAME, XCB_ATOM_STRING, 8,
		strlen(PROGRAM), PROGRAM);

	xcb_map_window(connection, window);

	xcb_flush(connection);

	pause();

	xcb_disconnect(connection);
	return 0;
}

See this instead: https://gist.github.com/Airblader/c59dd24d70095f813dd8183ef2e9f361