Index: src/interp/inter_cb.c
===================================================================
--- src/interp/inter_cb.c	(revision 40964)
+++ src/interp/inter_cb.c	(working copy)
@@ -299,6 +299,8 @@
     PMC     *sub;
     STRING  *sig_str;
     char    *p;
+    char     ch;
+    char    *sig_cstr;
     char     pasm_sig[4];
     INTVAL   i_param;
     PMC     *p_param;
@@ -311,7 +313,8 @@
     signature = VTABLE_getprop(interp, user_data, sc);
 
     sig_str   = VTABLE_get_string(interp, signature);
-    p         = sig_str->strstart;
+    sig_cstr  = Parrot_str_to_cstring(interp, sig_str);
+    p         = sig_cstr;
     ++p;     /* Skip return type */
 
     pasm_sig[0] = 'v';  /* no return value supported yet */
@@ -367,9 +370,12 @@
             param = Parrot_str_new(interp, external_data, 0);
             break;
         default:
+            ch = *p;
+            Parrot_str_free_cstring(sig_cstr);
             Parrot_ex_throw_from_c_args(interp, NULL, 1,
-                "unhandled signature char '%c' in run_cb", *p);
+                "unhandled signature char '%c' in run_cb", ch);
     }
+    Parrot_str_free_cstring(sig_cstr);
     pasm_sig[3] = '\0';
     Parrot_runops_fromc_args_event(interp, sub, pasm_sig,
             user_data, param);
Index: src/pmc/string.pmc
===================================================================
--- src/pmc/string.pmc	(revision 40964)
+++ src/pmc/string.pmc	(working copy)
@@ -734,17 +734,18 @@
                         enum_class_Integer));
 
         /* TODO verify encoding */
-        const STRING *me         = VTABLE_get_string(INTERP, SELF);
-        const char   *start      = me->strstart;
-        const char   * const end = start + me->bufused;
-        UINTVAL              i   = 0;
+        const STRING *me  = VTABLE_get_string(INTERP, SELF);
+        char         *str = Parrot_str_to_cstring(INTERP, me);
+        UINTVAL       i   = 0;
+        size_t        j   = 0;
+        size_t        len = strlen(str);
 
         if (base < 2 || base > 36)
             Parrot_ex_throw_from_c_args(INTERP, NULL, EXCEPTION_INVALID_OPERATION,
                     "invalid conversion to int - bad base %d", base);
 
-        while (start < end) {
-            const unsigned char c = *start;
+        while ( j < len) {
+            const unsigned char c = str[j];
             int dig;
 
             if (isdigit((unsigned char)c))
@@ -760,13 +761,17 @@
                 break;
 
             i = i * base + dig;
-            ++start;
+            j++;
         }
 
-        if (start < end)
+        if (j < len) {
+            char ch = str[j];
+            Parrot_str_free_cstring(str);
             Parrot_ex_throw_from_c_args(INTERP, NULL, EXCEPTION_INVALID_OPERATION,
-                    "invalid conversion to int - bad char %c", *start);
+                    "invalid conversion to int - bad char %c", ch);
+        }
 
+        Parrot_str_free_cstring(str);
         /* TODO: autopromote to BigInt instead of casting away the high bit */
         VTABLE_set_integer_native(INTERP, result, (INTVAL)i);
         RETURN(PMC *result);
Index: src/pmc/hash.pmc
===================================================================
--- src/pmc/hash.pmc	(revision 40964)
+++ src/pmc/hash.pmc	(working copy)
@@ -620,16 +620,20 @@
 
         for (j = 0; j < n; ++j) {
             STRING * const key       = VTABLE_shift_string(INTERP, iter);
+            char *         key_str;
+            size_t         i, str_len;
             int            all_digit = 1;
-            int            i;
             PMC           *val;
 
-            for (i = 0; i < (int)key->strlen; ++i) {
-                if (!isdigit((unsigned char)((const char *)key->strstart)[i])) {
+            key_str = Parrot_str_to_cstring(INTERP, key);
+            str_len = strlen(key_str);
+            for (i = 0; i < str_len; ++i) {
+                if (!isdigit(key_str[i])) {
                     all_digit = 0;
                     break;
                 }
             }
+            Parrot_str_free_cstring(key_str);
 
             if (all_digit) {
                 res = Parrot_str_append(INTERP, res, key);
Index: src/packdump.c
===================================================================
--- src/packdump.c	(revision 40964)
+++ src/packdump.c	(working copy)
@@ -224,9 +224,8 @@
                     ct_index = PackFile_find_in_const(interp, ct, key, PFC_STRING);
                     Parrot_io_printf(interp, "        PFC_OFFSET  => %ld\n", ct_index);
                     detail = ct->constants[ct_index];
-                    Parrot_io_printf(interp, "        DATA        => '%.*s'\n",
-                              (int)detail->u.string->bufused,
-                              (char *)detail->u.string->strstart);
+                    Parrot_io_printf(interp, "        DATA        => '%Ss'\n",
+                              detail->u.string);
                     Parrot_io_printf(interp, "       },\n");
                     }
                     break;