}

#endif /* _WIN32 */

/* ------------------------------------------------------------------------ */

int main ()
{
  GLuint err;
  if (GL_TRUE == glewCreateContext())
  {
    fprintf(stderr, "Error: glewCreateContext failed\n");
    glewDestroyContext();
    return 1;
  }
  glewExperimental = GL_TRUE;
  err = glewInit();
  if (GLEW_OK != err)
  {
    fprintf(stderr, "Error [main]: glewInit failed: %s\n", glewGetErrorString(err));
    glewDestroyContext();
    return 1;
  }
#ifdef _WIN32
  f = fopen("glewinfo.txt", "w");
  if (f == NULL) f = stdout;
#else
  f = stdout;
#endif
  fprintf(f, "---------------------------\n");
  fprintf(f, "    GLEW Extension Info\n");
  fprintf(f, "---------------------------\n\n");
  fprintf(f, "Running on a %s from %s\n", 
	  glGetString(GL_RENDERER), glGetString(GL_VENDOR));
  fprintf(f, "OpenGL version %s is supported\n", glGetString(GL_VERSION));
  fprintf(f, "GLEW version %s is supported\n", glewGetString(GLEW_VERSION));
  glewInfo();
#ifdef _WIN32
  wglewInfo();
#else
  glxewInfo();
#endif
  if (f != stdout) fclose(f);
  glewDestroyContext();
  return 0;
}

/* ------------------------------------------------------------------------ */

#ifdef _WIN32

HWND wnd = NULL;
HDC dc = NULL;
HGLRC rc = NULL;

GLboolean glewCreateContext ()
{
  WNDCLASS wc;
  PIXELFORMATDESCRIPTOR pfd;
  int pf;
  /* register window class */
  ZeroMemory(&wc, sizeof(WNDCLASS));
  wc.hInstance = GetModuleHandle(NULL);
  wc.lpfnWndProc = DefWindowProc;
  wc.lpszClassName = "GLEW";
  if (0 == RegisterClass(&wc)) return GL_TRUE;
  /* create window */
  wnd = CreateWindow("GLEW", "GLEW", 0, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, GetModuleHandle(NULL), NULL);
  if (NULL == wnd) return GL_TRUE;
  /* get the device context */
  dc = GetDC(wnd);
  if (NULL == dc) return GL_TRUE;
  /* find pixel format */
  ZeroMemory(&pfd, sizeof(PIXELFORMATDESCRIPTOR));
  pfd.nSize = sizeof(PIXELFORMATDESCRIPTOR);
  pfd.nVersion = 1;
  pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL;
  pf = ChoosePixelFormat(dc, &pfd);
  if (pf == 0) return GL_TRUE;
  /* set the pixel format for the dc */
  if (FALSE == SetPixelFormat(dc, pf, &pfd)) return GL_TRUE;
  /* create rendering context */
  rc = wglCreateContext(dc);
  if (NULL == rc) return GL_TRUE;
  if (FALSE == wglMakeCurrent(dc, rc)) return GL_TRUE;
  return GL_FALSE;
}

void glewDestroyContext ()
{
  if (NULL != rc) wglMakeCurrent(NULL, NULL);
  if (NULL != rc) wglDeleteContext(wglGetCurrentContext());
  if (NULL != wnd && NULL != dc) ReleaseDC(wnd, dc);
  if (NULL != wnd) DestroyWindow(wnd);
  UnregisterClass("GLEW", GetModuleHandle(NULL));
}

#else

/* ------------------------------------------------------------------------ */

#  ifdef __APPLE__

GLboolean glewCreateContext ()
{
}

void glewDestroyContext ()
{
}

#  else /* __linux || __sgi */

/* ------------------------------------------------------------------------ */

Display* dpy = NULL;
XVisualInfo* vi = NULL;
GLXContext ctx = NULL;
Window wnd;
Colormap cmap;

GLboolean glewCreateContext ()
{
  int attrib[] = { GLX_RGBA, None };
  int erb, evb;
  XSetWindowAttributes swa;
  /* open display */
  dpy = XOpenDisplay(NULL);
  if (NULL == dpy) return GL_TRUE;
  /* query for glx */
  if (!glXQueryExtension(dpy, &erb, &evb)) return GL_TRUE;
  /* choose visual */
  vi = glXChooseVisual(dpy, DefaultScreen(dpy), attrib);
  if (NULL == vi) return GL_TRUE;
  /* create context */
  ctx = glXCreateContext(dpy, vi, None, True);
  if (NULL == ctx) return GL_TRUE;
  /* create window */
  //wnd = XCreateSimpleWindow(dpy, RootWindow(dpy, vi->screen), 0, 0, 1, 1, 1, 0, 0);
  cmap = XCreateColormap(dpy, RootWindow(dpy, vi->screen), vi->visual, AllocNone);
  //swa.colormap = cmap;
  swa.border_pixel = 0;
  swa.colormap = cmap;
  wnd = XCreateWindow(dpy, RootWindow(dpy, vi->screen), 0, 0, 256, 256, 0, vi->depth,
		      InputOutput, vi->visual, CWBorderPixel | CWColormap, &swa);
 /* make context current */
  if (!glXMakeCurrent(dpy, wnd, ctx)) return GL_TRUE;
  return GL_FALSE;
}

void glewDestroyContext ()
{
  if (NULL != dpy && NULL != ctx) glXDestroyContext(dpy, ctx);
  if (NULL != dpy) XDestroyWindow(dpy, wnd);
  if (NULL != dpy) XFreeColormap(dpy, cmap);
  if (NULL != vi) XFree(vi);
  if (NULL != dpy) XCloseDisplay(dpy);
}

#  endif /* __linux || __sgi */

#endif