diff --git a/src/threads.c b/src/threads.c
index c0509f7a468635f0d77c62ee59b2232e8dfe76d0..5c41e80ab95e9cbd5b46f629f71ac463af320a9f 100644
--- a/src/threads.c
+++ b/src/threads.c
@@ -149,7 +149,7 @@ PMOD_EXPORT int low_nt_create_thread(unsigned Pike_stack_size,
   }
   else
   {
-    return 1;
+    return errno;
   }
 }