diff --git a/Include/httpClient/pal.h b/Include/httpClient/pal.h
index 0c3c4f7e..bd3e65e7 100644
--- a/Include/httpClient/pal.h
+++ b/Include/httpClient/pal.h
@@ -374,6 +374,10 @@ typedef struct _LIST_ENTRY {
 #define _Deref_out_opt_
 #endif
 
+#ifndef _Writable_elements_
+#define _Writable_elements_(size)
+#endif
+
 #ifndef __analysis_assume
 #define __analysis_assume(condition)
 #endif