--- Compress-LZF/LZF.xs	2008/01/09 20:41:18	1.25
+++ Compress-LZF/LZF.xs	2008/09/22 02:15:43	1.26
@@ -285,6 +285,7 @@
                      && SvTYPE(sv) != SVt_PVMG)) /* mstore */
           {
             int deref = !SvROK (sv);
+            char *pv;
 
             if (!storable_mstore)
               {
@@ -306,11 +307,12 @@
             SPAGAIN;
 
             sv = POPs;
+            pv = SvPV_nolen (sv);
 
-            if (SvPVX (sv)[0] == MAGIC_R)
+            if (*pv == MAGIC_R)
               {
                 if (deref)
-                  SvPVX (sv)[0] = MAGIC_R_deref;
+                  *pv = MAGIC_R_deref;
               }
             else
               {