diff --git a/src/lib_json/json_value.cpp b/src/lib_json/json_value.cpp
index bbfa12c..e195594 100644
--- a/src/lib_json/json_value.cpp
+++ b/src/lib_json/json_value.cpp
@@ -157,7 +157,7 @@ static inline void releaseStringValue(char* value, unsigned length) {
 static inline void releasePrefixedStringValue(char* value) {
   free(value);
 }
-static inline void releaseStringValue(char* value, unsigned length) {
+static inline void releaseStringValue(char* value, unsigned) {
   free(value);
 }
 #endif // JSONCPP_USING_SECURE_MEMORY