diff --git a/lib/dns/sec/openssl/include/openssl/stack.h b/lib/dns/sec/openssl/include/openssl/stack.h
index 8d57833339..80cf81c07a 100644
--- a/lib/dns/sec/openssl/include/openssl/stack.h
+++ b/lib/dns/sec/openssl/include/openssl/stack.h
@@ -70,7 +70,7 @@ typedef struct stack_st
 	int sorted;
 
 	int num_alloc;
-	int (*comp)();
+	int (*comp)(char **, char **);
 	} STACK;
 
 
diff --git a/lib/dns/sec/openssl/stack.c b/lib/dns/sec/openssl/stack.c
index 6aae5aa410..b4a212eb30 100644
--- a/lib/dns/sec/openssl/stack.c
+++ b/lib/dns/sec/openssl/stack.c
@@ -265,7 +265,7 @@ void sk_zero(STACK *st)
 	st->num=0;
 	}
 
-void sk_pop_free(STACK *st, void (*func)())
+void sk_pop_free(STACK *st, void (*func)(char *))
 	{
 	int i;