GLboolean GLEWAPIENTRY glewGetExtension (const char* name)
{    
  const GLubyte* start;
  const GLubyte* end;
  start = (const GLubyte*)glGetString(GL_EXTENSIONS);
  if (start == 0)
    return GL_FALSE;
  end = start + _glewStrLen(start);
  return _glewSearchExtension(name, start, end);
}
GLboolean glxewGetExtension (const char* name)
{    
  const GLubyte* start;
  const GLubyte* end;

  if (glXGetCurrentDisplay == NULL) return GL_FALSE;
  start = (const GLubyte*)glXGetClientString(glXGetCurrentDisplay(), GLX_EXTENSIONS);
  if (0 == start) return GL_FALSE;
  end = start + _glewStrLen(start);
  return _glewSearchExtension(name, start, end);
}