static void error_callback(int error, const char* description)
{
    fprintf(stderr, "Error: %s\n", description);
}

static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GLFW_TRUE);
}

static float nrand(void)
{
    return (float) rand() / (float) RAND_MAX;
}

int main(void)
{
    GLFWwindow* window;

    srand((unsigned int) time(NULL));

    glfwSetErrorCallback(error_callback);

    if (!glfwInit())
        exit(EXIT_FAILURE);

    window = glfwCreateWindow(640, 480, "Event Wait Timeout Test", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        exit(EXIT_FAILURE);
    }

    glfwMakeContextCurrent(window);
    gladLoadGL(glfwGetProcAddress);
    glfwSetKeyCallback(window, key_callback);

    while (!glfwWindowShouldClose(window))
    {
        int width, height;
        float r = nrand(), g = nrand(), b = nrand();
        float l = (float) sqrt(r * r + g * g + b * b);

        glfwGetFramebufferSize(window, &width, &height);

        glViewport(0, 0, width, height);
        glClearColor(r / l, g / l, b / l, 1.f);
        glClear(GL_COLOR_BUFFER_BIT);
        glfwSwapBuffers(window);

        glfwWaitEventsTimeout(1.0);
    }

    glfwDestroyWindow(window);

    glfwTerminate();
    exit(EXIT_SUCCESS);
}

