diff --git a/Modules/_io/winconsoleio.c b/Modules/_io/winconsoleio.c
index 30d1c76..b85c11b 100644
--- a/Modules/_io/winconsoleio.c
+++ b/Modules/_io/winconsoleio.c
@@ -964,6 +964,9 @@
     if (!self->writable)
         return err_mode("writing");
 
+    if (!b->len) {
+        return PyLong_FromLong(0);
+    }
     if (b->len > BUFMAX)
         len = BUFMAX;
     else