programming question: u_char vs. uint32_t

[Andrew]

Hello all,

I'm reading through /usr/src/sys/dd/dd.h, and I noticed the following
lines:

39      u_char          *db;            /* buffer address */
40	u_char          *dbp;           /* current buffer I/O address */

Why was u_char used instead of uint32_t? Aren't pointers always 32 bits
on a 32 bit machine?

Thanks,
Andrew