/* query opengl extensions string */
  extStart = glGetString(GL_EXTENSIONS);
  if (extStart == 0)
    extStart = (const GLubyte*)"";
  extEnd = extStart + _glewStrLen(extStart);

  while (extStart < extEnd)
  {
    GLuint len = _glewStrCLen(extStart, ' ');
    struct initflag *ptr = in_word_set(extStart, len);

    if (ptr != NULL && ptr->flag != NULL) {
#ifdef GLEW_MX
      *(GLboolean *)((char *)ctx + (size_t)(ptr->flag)) = GL_TRUE;
#else
      *ptr->flag = GL_TRUE;
#endif
    }
    extStart += len + 1;
  }

  /* initialize extensions */