diff --git a/c_src/jiffy.h b/c_src/jiffy.h
index 6d869a5..6a7d73a 100644
--- a/c_src/jiffy.h
+++ b/c_src/jiffy.h
@@ -8,10 +8,22 @@
 
 #define DEFAULT_BYTES_PER_ITER 2048
 
+#ifndef UNUSED
+#define UNUSED  __attribute__((unused))
+#endif
+
 #define MAP_TYPE_PRESENT \
     ((ERL_NIF_MAJOR_VERSION == 2 && ERL_NIF_MINOR_VERSION >= 6) \
     || (ERL_NIF_MAJOR_VERSION > 2))
 
+static int UNUSED should_yield(size_t used, size_t limit) {
+    if(limit == 0 || used < limit) {
+        return 0;
+    }
+
+    return 1;
+}
+
 typedef struct {
     ERL_NIF_TERM    atom_ok;
     ERL_NIF_TERM    atom_error;
@@ -44,7 +56,6 @@ ERL_NIF_TERM make_error(jiffy_st* st, ErlNifEnv* env, const char* error);
 ERL_NIF_TERM make_obj_error(jiffy_st* st, ErlNifEnv* env, const char* error,
         ERL_NIF_TERM obj);
 int get_bytes_per_iter(ErlNifEnv* env, ERL_NIF_TERM val, size_t* bpi);
-int should_yield(size_t used, size_t limit);
 int consume_timeslice(ErlNifEnv* env, size_t used, size_t limit);
 
 ERL_NIF_TERM decode_init(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
diff --git a/c_src/util.c b/c_src/util.c
index c30a6d7..f9f3bfc 100644
--- a/c_src/util.c
+++ b/c_src/util.c
@@ -62,16 +62,6 @@ get_bytes_per_iter(ErlNifEnv* env, ERL_NIF_TERM val, size_t* bpi)
     return 1;
 }
 
-int
-should_yield(size_t used, size_t limit)
-{
-    if(limit == 0 || used < limit) {
-        return 0;
-    }
-
-    return 1;
-}
-
 int
 consume_timeslice(ErlNifEnv* env, size_t used, size_t limit)
 {