diff --git a/RSSwizzle/RSSwizzle.m b/RSSwizzle/RSSwizzle.m
index 3145daa..e5403f1 100644
--- a/RSSwizzle/RSSwizzle.m
+++ b/RSSwizzle/RSSwizzle.m
@@ -337,7 +337,7 @@ static void swizzle(Class classToSwizzle,
 }
 
 
-static NSMutableDictionary *swizzledClassesDictionary(){
+static NSMutableDictionary *swizzledClassesDictionary(void){
     static NSMutableDictionary *swizzledClasses;
     static dispatch_once_t onceToken;
     dispatch_once(&onceToken, ^{