Bit field definition ?

[Dan Nelson]

In the last episode (Oct 08), Li, Qing said:
> 	The bit fields "th_x2" and "th_off" in "struct tcphdr",
> 	even though defined as "u_int", actually occupies 1 byte.

    u_int   th_x2:4,        /* (unused) */
        th_off:4;       /* data offset */

The :4 after each variable means 4 bits long, so both fields together
take up 8 bits = 1 byte.  That's the whole purpose of bitfields :)

-- 
	Dan Nelson
	dnelson at allantgroup.com