ret = Xalloc (amount); if (ret) bzero ((char *) ret, (int) amount); else if ((long)amount > 0)
if (amount == 0) return NULL;  ret = Xalloc(amount); if (!ret)
XNFcalloc(unsigned long amount){    unsigned long   *ret;    ret = Xalloc (amount);    if (ret)	bzero ((char *) ret, (int) amount);    else if ((long)amount > 0)        FatalError("Out of memory");    return ret;}