diff --git a/ssl/internal.h b/ssl/internal.h
index 937c9fe..b67637d 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -342,7 +342,7 @@
 };
 
 // CBBFinishArray behaves like |CBB_finish| but stores the result in an Array.
-bool CBBFinishArray(CBB *cbb, Array<uint8_t> *out);
+OPENSSL_EXPORT bool CBBFinishArray(CBB *cbb, Array<uint8_t> *out);
 
 
 // Protocol versions.