1 files changed, 1 insertions, 0 deletions
diff --git a/win32/win32.c b/win32/win32.c
index b16f595d55..fc6b587b20 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -1839,6 +1839,7 @@ setgid(rb_gid_t gid)
 int
 ioctl(int i, int u, ...)
 {
+    errno = EINVAL;
     return -1;
 }