diff --git a/calmwm.h b/calmwm.h
index e80f5d0..07e223c 100644
--- a/calmwm.h
+++ b/calmwm.h
@@ -512,7 +512,7 @@ void			 xev_loop(void);
 
 void			 xu_btn_grab(Window, int, u_int);
 void			 xu_btn_ungrab(Window, int, u_int);
-int			 xu_getprop(Window, Atom, Atom, long, u_char **);
+int			 xu_getprop(Window, Atom, Atom, long, unsigned char **);
 int			 xu_get_wm_state(Window, int *);
 int			 xu_getstrprop(Window, Atom, char **);
 void			 xu_key_grab(Window, u_int, KeySym);
diff --git a/client.c b/client.c
index 9a90588..ee069c5 100644
--- a/client.c
+++ b/client.c
@@ -841,7 +841,7 @@ client_getmwmhints(struct client_ctx *cc)
 	struct mwm_hints	*mwmh;
 
 	if (xu_getprop(cc->win, cwmh[_MOTIF_WM_HINTS], cwmh[_MOTIF_WM_HINTS],
-	    PROP_MWM_HINTS_ELEMENTS, (u_char **)&mwmh) == MWM_NUMHINTS)
+	    PROP_MWM_HINTS_ELEMENTS, (unsigned char **)&mwmh) == MWM_NUMHINTS)
 		if (mwmh->flags & MWM_HINTS_DECORATIONS &&
 		    !(mwmh->decorations & MWM_DECOR_ALL) &&
 		    !(mwmh->decorations & MWM_DECOR_BORDER))
diff --git a/group.c b/group.c
index e025be6..9e388fd 100644
--- a/group.c
+++ b/group.c
@@ -419,7 +419,7 @@ group_update_names(struct screen_ctx *sc)
 	int		 i = 0, j = 0, nstrings = 0, n = 0, setnames = 0;
 
 	if ((j = xu_getprop(sc->rootwin, ewmh[_NET_DESKTOP_NAMES],
-	    cwmh[UTF8_STRING], 0xffffff, (u_char **)&prop_ret)) > 0) {
+	    cwmh[UTF8_STRING], 0xffffff, (unsigned char **)&prop_ret)) > 0) {
 		prop_ret[j - 1] = '\0'; /* paranoia */
 		while (i < j) {
 			if (prop_ret[i++] == '\0')
diff --git a/xutil.c b/xutil.c
index 7912cb8..543b8b0 100644
--- a/xutil.c
+++ b/xutil.c
@@ -106,7 +106,7 @@ xu_key_grab(Window win, u_int mask, KeySym keysym)
 }
 
 int
-xu_getprop(Window win, Atom atm, Atom type, long len, u_char **p)
+xu_getprop(Window win, Atom atm, Atom type, long len, unsigned char **p)
 {
 	Atom	 realtype;
 	u_long	 n, extra;
@@ -160,7 +160,7 @@ xu_get_wm_state(Window win, int *state)
 	long	*p = NULL;
 
 	if (xu_getprop(win, cwmh[WM_STATE], cwmh[WM_STATE], 2L,
-	    (u_char **)&p) <= 0)
+	    (unsigned char **)&p) <= 0)
 		return (-1);
 
 	*state = (int)*p;
@@ -331,7 +331,7 @@ xu_ewmh_get_net_wm_state(struct client_ctx *cc, int *n)
 	Atom	*state, *p = NULL;
 
 	if ((*n = xu_getprop(cc->win, ewmh[_NET_WM_STATE], XA_ATOM, 64L,
-	    (u_char **)&p)) <= 0)
+	    (unsigned char **)&p)) <= 0)
 		return (NULL);
 
 	state = xcalloc(*n, sizeof(Atom));