diff --git a/ChangeLog b/ChangeLog
index babd5e3f..9706f878 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -19,7 +19,8 @@ May 2023
     on automatic selection by TLS library.
     HTTPS tests: changed certificate hash algorithm from SHA-1 to SHA-256
     as SHA-1 is already blocked by some libs/OSes.
-    W32 VS projects: supported ARM and ARM64. -EG
+    W32 VS projects: supported ARM and ARM64.
+    Fixed compiler warning on x32. -EG
 
 April 2023
     Fixed processing of folded headers.
diff --git a/src/microhttpd/response.c b/src/microhttpd/response.c
index 41665754..99a7f188 100644
--- a/src/microhttpd/response.c
+++ b/src/microhttpd/response.c
@@ -1248,8 +1248,10 @@ MHD_create_response_from_data (size_t size,
 
   if ((NULL == data) && (size > 0))
     return NULL;
+#if SIZEOF_SIZE_T >= SIZEOF_UINT64_T
   if (MHD_SIZE_UNKNOWN == size)
     return NULL;
+#endif /* SIZEOF_SIZE_T >= SIZEOF_UINT64_T */
   if (NULL == (response = MHD_calloc_ (1, sizeof (struct MHD_Response))))
     return NULL;
   response->fd = -1;