diff --git a/library/entropy_poll.c b/library/entropy_poll.c
index 270eb86..a0c9b7b 100644
--- a/library/entropy_poll.c
+++ b/library/entropy_poll.c
@@ -50,6 +50,7 @@
                            size_t *olen )
 {
     HCRYPTPROV provider;
+    ((void) data);
     *olen = 0;
 
     if( CryptAcquireContext( &provider, NULL, NULL,