re.c:1438
int
rb_kcode()
{
    switch (reg_kcode) {
      case KCODE_EUC:
	return MBCTYPE_EUC;
      case KCODE_SJIS:
	return MBCTYPE_SJIS;
      case KCODE_UTF8:
	return MBCTYPE_UTF8;
      case KCODE_NONE:
	return MBCTYPE_ASCII;
    }
    rb_bug("wrong reg_kcode value (0x%x)", reg_kcode);
}
