diff -r fcfe8c5e9fe1 -r 27e67e725d35 ucx/dlist.c
--- a/ucx/dlist.c	Thu Oct 11 08:42:56 2012 +0200
+++ b/ucx/dlist.c	Thu Oct 11 11:42:31 2012 +0200
@@ -1,6 +1,7 @@
 #include "dlist.h"
 
-UcxDlist *ucx_dlist_clone(UcxDlist *l, copy_func fnc, void *data) {
+UcxDlist *restrict ucx_dlist_clone(UcxDlist *restrict l,
+        copy_func fnc, void *data) {
     UcxDlist *ret = NULL;
     while (l != NULL) {
         if (fnc != NULL) {
@@ -13,7 +14,8 @@
     return ret;
 }
 
-int ucx_dlist_equals(UcxDlist *l1, UcxDlist *l2, cmp_func fnc, void* data) {
+int ucx_dlist_equals(const UcxDlist *l1, const UcxDlist *l2,
+        cmp_func fnc, void* data) {
     if (l1 == l2) return 1;
     
     while (l1 != NULL && l2 != NULL) {
@@ -66,7 +68,7 @@
     return nl;
 }
 
-UcxDlist *ucx_dlist_concat(UcxDlist *l1, UcxDlist *l2) {
+UcxDlist *ucx_dlist_concat(UcxDlist *restrict l1, UcxDlist *restrict l2) {
     if (l1 == NULL) {
         return l2;
     } else {
@@ -77,32 +79,32 @@
     }
 }
 
-UcxDlist *ucx_dlist_last(UcxDlist *l) {
+UcxDlist *ucx_dlist_last(const UcxDlist *l) {
     if (l == NULL) return NULL;
     
-    UcxDlist *e = l;
+    const UcxDlist *e = l;
     while (e->next != NULL) {
         e = e->next;
     }
-    return e;
+    return (UcxDlist*)e;
 }
 
-UcxDlist *ucx_dlist_get(UcxDlist *l, int index) {
+UcxDlist *ucx_dlist_get(const UcxDlist *l, int index) {
     if (l == NULL) return NULL;
 
-    UcxDlist *e = l;
+    const UcxDlist *e = l;
     while (e->next != NULL && index > 0) {
         e = e->next;
         index--;
     }
     
-    return index == 0 ? e : NULL;
+    return (UcxDlist*)(index == 0 ? e : NULL);
 }
 
-size_t ucx_dlist_size(UcxDlist *l) {
+size_t ucx_dlist_size(const UcxDlist *l) {
     if (l == NULL) return 0;
     
-    UcxDlist *e = l;
+    const UcxDlist *e = l;
     size_t s = 1;
     while (e->next != NULL) {
         e = e->next;
@@ -113,14 +115,14 @@
 }
 
 UcxDlist *ucx_dlist_sort_merge(int length,
-        UcxDlist* ls, UcxDlist* rs, UcxDlist* le, UcxDlist* re,
+        UcxDlist* restrict ls, UcxDlist* restrict le, UcxDlist* restrict re,
         cmp_func fnc, void* data) {
     UcxDlist *sorted[length];
     UcxDlist *rc, *lc;
 
-    lc = ls; rc = rs;
+    lc = ls; rc = le;
     int n = 0;
-    while (lc != le && rc != re) {
+    while (lc && lc != le && rc != re) {
         if (fnc(lc->data, rc->data, data) <= 0) {
             sorted[n] = lc;
             lc = lc->next;
@@ -130,12 +132,12 @@
         }
         n++;
     }
-    while (lc != le) {
+    while (lc && lc != le) {
         sorted[n] = lc;
         lc = lc->next;
         n++;
     }
-    while (rc != re) {
+    while (rc && rc != re) {
         sorted[n] = rc;
         rc = rc->next;
         n++;
@@ -160,7 +162,7 @@
     UcxDlist *lc;
     int ln = 1;
 
-    UcxDlist *ls = l, *le;
+    UcxDlist *restrict ls = l, *restrict le, *restrict re;
     lc = ls;
     while (lc->next != NULL && fnc(lc->next->data, lc->data, data) > 0) {
         lc = lc->next;
@@ -168,13 +170,12 @@
     }
     le = lc->next;
 
-    UcxDlist *rs = le, *re;
-    if (rs == NULL) {
+    if (le == NULL) {
         return l; // this list is already sorted :)
     } else {
         UcxDlist *rc;
         int rn = 1;
-        rc = rs;
+        rc = le;
         while (rc->next != NULL && fnc(rc->next->data, rc->data, data) > 0) {
             rc = rc->next;
             rn++;
@@ -190,27 +191,26 @@
 
         // {ls,...,le->prev} and {rs,...,re->prev} are sorted - merge them
         UcxDlist *sorted = ucx_dlist_sort_merge(ln+rn,
-                ls, rs, le, re,
+                ls, le, re,
                 fnc, data);
 
         // merge sorted list with (also sorted) remainder
         l = ucx_dlist_sort_merge(ln+rn+remainder_length,
-                sorted, remainder, NULL, NULL,
-                fnc, data);
+                sorted, remainder, NULL, fnc, data);
 
         return l;
     }
 }
 
 /* dlist specific functions */
-UcxDlist *ucx_dlist_first(UcxDlist *l) {
+UcxDlist *ucx_dlist_first(const UcxDlist *l) {
     if (l == NULL) return NULL;
     
-    UcxDlist *e = l;
+    const UcxDlist *e = l;
     while (e->prev != NULL) {
         e = e->prev;
     }
-    return e;
+    return (UcxDlist *)e;
 }
 
 UcxDlist *ucx_dlist_remove(UcxDlist *l, UcxDlist *e) {