获取 buf 里的 symbol 

cbuf = BufListCount()msg(cbuf)ibuf = 0while (ibuf < cbuf){    hbuf = BufListItem(ibuf)    isymMax = GetBufSymCount(hbuf)    msg(isymMax)    isym = 0    while (isym < isymMax)    {        symname = GetBufSymLocation(hbuf, isym)        msg(symname)        isym = isym + 1    }    ibuf = ibuf + 1}