diff -bu Digest-BLAKE2-0.01-7N4L0h/in/src/BLAKE2x.xs~ Digest-BLAKE2-0.01-7N4L0h/in/src/BLAKE2x.xs
--- Digest-BLAKE2-0.01-7N4L0h/in/src/BLAKE2x.xs~	2013-02-09 21:47:42.000000000 -0600
+++ Digest-BLAKE2-0.01-7N4L0h/in/src/BLAKE2x.xs	2014-03-22 14:40:25.000000000 -0500
@@ -24,7 +24,7 @@
 };
 
 inline static SV *
-encode_string(const char *src, enum encode_type type) {
+encode_string(pTHX_ const char *src, enum encode_type type) {
     int encoded_len;
 
     switch (type) {
@@ -154,5 +154,5 @@
     }
     blake2x_final(state, out, BLAKE2x_OUTBYTES);
     Safefree(state);
-    ST(0) = encode_string((char *)out, ix);
+    ST(0) = encode_string(aTHX_ (char *)out, ix);
     XSRETURN(1);