unsigned long tt;
static void swap_screen (int which) {    int t;    unsigned long tt;    tree234 *ttr;    if (which == alt_which)	return;    alt_which = which;    ttr = alt_screen; alt_screen = screen; screen = ttr;    t = curs.x; curs.x = alt_x; alt_x = t;    t = curs.y; curs.y = alt_y; alt_y = t;    t = marg_t; marg_t = alt_t; alt_t = t;    t = marg_b; marg_b = alt_b; alt_b = t;    t = dec_om; dec_om = alt_om; alt_om = t;    t = wrap; wrap = alt_wrap; alt_wrap = t;    t = wrapnext; wrapnext = alt_wnext; alt_wnext = t;    t = insert; insert = alt_ins; alt_ins = t;    t = cset; cset = alt_cset; alt_cset = t;    fix_cpos;}