diff --git a/config.go b/config.go
index 3921fe9..153fbd6 100644
--- a/config.go
+++ b/config.go
@@ -109,7 +109,7 @@ func (c *Conn) FileControl(schema string, op FcntlOpcode, arg ...any) (any, erro
 	default:
 		return nil, MISUSE
 
-	case FCNTL_RESET_CACHE:
+	case FCNTL_RESET_CACHE, FCNTL_NULL_IO:
 		rc = res_t(c.call("sqlite3_file_control",
 			stk_t(c.handle), stk_t(schemaPtr),
 			stk_t(op), 0))
diff --git a/const.go b/const.go
index 522f68b..e4fc829 100644
--- a/const.go
+++ b/const.go
@@ -280,6 +280,7 @@ const (
 	FCNTL_DATA_VERSION        FcntlOpcode = 35
 	FCNTL_RESERVE_BYTES       FcntlOpcode = 38
 	FCNTL_RESET_CACHE         FcntlOpcode = 42
+	FCNTL_NULL_IO             FcntlOpcode = 43
 )
 
 // LimitCategory are the available run-time limit categories.
diff --git a/tests/config_test.go b/tests/config_test.go
index 4272ad3..f8492d3 100644
--- a/tests/config_test.go
+++ b/tests/config_test.go
@@ -114,6 +114,7 @@ func TestConn_FileControl(t *testing.T) {
 			t.Errorf("got %v, want MISUSE", err)
 		}
 	})
+
 	t.Run("FCNTL_RESET_CACHE", func(t *testing.T) {
 		o, err := db.FileControl("", sqlite3.FCNTL_RESET_CACHE)
 		if err != nil {
@@ -237,6 +238,16 @@ func TestConn_FileControl(t *testing.T) {
 			t.Errorf("got %v, want LOCK_EXCLUSIVE", o)
 		}
 	})
+
+	t.Run("FCNTL_NULL_IO", func(t *testing.T) {
+		o, err := db.FileControl("", sqlite3.FCNTL_NULL_IO)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if o != nil {
+			t.Errorf("got %v, want nil", o)
+		}
+	})
 }
 
 func TestConn_Limit(t *testing.T) {
diff --git a/vfs/const.go b/vfs/const.go
index b789d12..11afb12 100644
--- a/vfs/const.go
+++ b/vfs/const.go
@@ -234,6 +234,7 @@ const (
 	_FCNTL_CKSM_FILE             _FcntlOpcode = 41
 	_FCNTL_RESET_CACHE           _FcntlOpcode = 42
 	_FCNTL_NULL_IO               _FcntlOpcode = 43
+	_FCNTL_BLOCK_ON_CONNECT      _FcntlOpcode = 44
 )
 
 // https://sqlite.org/c3ref/c_shm_exclusive.html
@@ -246,6 +247,6 @@ const (
 	_SHM_EXCLUSIVE _ShmFlag = 8
 
 	_SHM_NLOCK = 8
-	_SHM_BASE  = 120
+	_SHM_BASE  = (22 + _SHM_NLOCK) * 4
 	_SHM_DMS   = _SHM_BASE + _SHM_NLOCK
 )
diff --git a/vfs/shm_windows.go b/vfs/shm_windows.go
index 7cc5b2a..0be523a 100644
--- a/vfs/shm_windows.go
+++ b/vfs/shm_windows.go
@@ -26,7 +26,6 @@ type vfsShm struct {
 	ptrs     []ptr_t
 	stack    [1]stk_t
 	fileLock bool
-	blocking bool
 	sync.Mutex
 }
 
diff --git a/vfs/vfs.go b/vfs/vfs.go
index c70507c..2656ddb 100644
--- a/vfs/vfs.go
+++ b/vfs/vfs.go
@@ -381,6 +381,10 @@ func vfsFileControlImpl(ctx context.Context, mod api.Module, file File, op _Fcnt
 			file.SetDB(ctx.Value(util.ConnKey{}))
 			return _OK
 		}
+
+	case _FCNTL_NULL_IO:
+		file.Close()
+		return _OK
 	}
 
 	return _NOTFOUND