A simple program to grab virtual core keyboard & pointer for 3 seconds.

grab-x11.c

/* -*- coding: utf-8; indent-tabs-mode: nil; tab-width: 4; c-basic-offset: 4; -*- */
/**
 * Copyright (C) 2013 Shih-Yuan Lee (FourDollars) <fourdollars@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <gdk/gdk.h>
#include <gdk/gdkx.h>

static const char *
grab_string (int status)
{
    switch (status) {
        case GDK_GRAB_SUCCESS:          return "GrabSuccess";
        case GDK_GRAB_ALREADY_GRABBED:  return "AlreadyGrabbed";
        case GDK_GRAB_INVALID_TIME:     return "GrabInvalidTime";
        case GDK_GRAB_NOT_VIEWABLE:     return "GrabNotViewable";
        case GDK_GRAB_FROZEN:           return "GrabFrozen";
        default:
                                        {
                                            static char foo [255];
                                            sprintf (foo, "unknown status: %d", status);
                                            return foo;
                                        }
    }
}

static const char *
device_source (GdkDevice *device)
{
    switch (gdk_device_get_source (device)) {
        case GDK_SOURCE_MOUSE: return "Mouse";
        case GDK_SOURCE_PEN: return "Pen";
        case GDK_SOURCE_ERASER: return "Eraser";
        case GDK_SOURCE_CURSOR: return "Cursor";
        case GDK_SOURCE_KEYBOARD: return "Keyboard";
        case GDK_SOURCE_TOUCHSCREEN: return "Touchscreen";
        case GDK_SOURCE_TOUCHPAD: return "Touchpad";
        default: return "Unknown";
    }
}

int
main(int argc, char* argv[])
{
    GdkDisplay *display;
    GdkWindow  *window;
    GdkScreen  *screen;
    GdkGrabStatus status;
    GdkDeviceManager *manager;
    GList *list, *it;

    gdk_init (NULL, NULL);

    display = gdk_display_get_default ();
    screen = gdk_display_get_default_screen (display);
    window = gdk_screen_get_root_window (screen);
    manager = gdk_display_get_device_manager (display);

    list = gdk_device_manager_list_devices (manager, GDK_DEVICE_TYPE_MASTER);

    for (it = list; it; it = it->next) {
        GdkDevice *device = (GdkDevice*) it->data;
        printf ("name: %s\nsource: %s\n", gdk_device_get_name (device), device_source (device));
        status = gdk_device_grab (device, window, GDK_OWNERSHIP_NONE, TRUE, GDK_ALL_EVENTS_MASK, NULL, GDK_CURRENT_TIME);
        printf ("status: %s\n", grab_string (status));
    }

    sleep(3);

    for (it = list; it; it = it->next) {
        GdkDevice *device = (GdkDevice*) it->data;
        gdk_device_ungrab (device, GDK_CURRENT_TIME);
    }

    g_list_free (list);

    return 0;
}

/* vim:set fileencodings=utf-8 tabstop=4 expandtab shiftwidth=4 softtabstop=4: */