diff --git a/glx-dbl-bare/glx-dbl-bare.c b/glx-dbl-bare/glx-dbl-bare.c
index bc595b6..87ccc80 100644
--- a/glx-dbl-bare/glx-dbl-bare.c
+++ b/glx-dbl-bare/glx-dbl-bare.c
@@ -1,9 +1,15 @@
 
-#include  <GL/glx.h>
-#include  <GL/gl.h>
-#include  <unistd.h>
+#include <GL/glx.h>
+#include <GL/gl.h>
+#include <unistd.h>
+#include <stdio.h>
 
-static int attributeList[] = { GLX_RGBA, None };
+static int attributeList[] = {
+    GLX_RGBA,
+    GLX_DOUBLEBUFFER,
+    GLX_DEPTH_SIZE, 24,
+    None
+};
 
 static Bool WaitForNotify(Display *d, XEvent *e, char *arg)
 {
@@ -21,11 +27,29 @@ int main(int argc, char **argv)
     XEvent event;
 
     /* get a connection */
-    dpy = XOpenDisplay(0);
+    dpy = XOpenDisplay(NULL);
+    if (dpy == NULL)
+    {
+        fprintf(stderr, "XOpenDisplay() returned NULL\n");
+        return 2;
+    }
+
     /* get an appropriate visual */
     vi = glXChooseVisual(dpy, DefaultScreen(dpy), attributeList);
+    if (vi == NULL)
+    {
+        fprintf(stderr, "glXChooseVisual() returned NULL\n");
+        return 2;
+    }
+
     /* create a GLX context */
-    cx = glXCreateContext(dpy, vi, 0, GL_FALSE);
+    cx = glXCreateContext(dpy, vi, NULL, GL_TRUE);
+    if (cx == NULL)
+    {
+        fprintf(stderr, "glXCreateContext() returned NULL\n");
+        return 2;
+    }
+
     /* create a color map */
     cmap = XCreateColormap(dpy, RootWindow(dpy, vi->screen),
             vi->visual, AllocNone);
@@ -36,15 +60,28 @@ int main(int argc, char **argv)
     swa.event_mask = StructureNotifyMask;
     win = XCreateWindow(dpy, RootWindow(dpy, vi->screen), 0, 0, 100, 100,
             0, vi->depth, InputOutput, vi->visual,
-            CWBorderPixel|CWColormap|CWEventMask, &swa);
+            CWBorderPixel | CWColormap | CWEventMask, &swa);
     XMapWindow(dpy, win);
     XIfEvent(dpy, &event, WaitForNotify, (char*)win);
     /* connect the context to the window */
-    glXMakeCurrent(dpy, win, cx);
+    if (glXMakeCurrent(dpy, win, cx) == GL_FALSE)
+    {
+        fprintf(stderr, "glXMakeCurrent() returned false\n");
+        return 2;
+    }
+
+    /* setup */
+    glEnable(GL_DEPTH_TEST);
+
     /* clear the buffer */
-    glClearColor(1,1,0,1);
-    glClear(GL_COLOR_BUFFER_BIT);
-    glFlush();
+    glClearColor(1, 1, 0, 1);
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+    glXSwapBuffers(dpy, win);
+
     /* wait a while */
-    sleep(10);
+    sleep(5);
+
+    /* teardown */
+    XFree(vi);
+    XCloseDisplay(dpy);
 }