diff --git a/include/polarssl/error.h b/include/polarssl/error.h
index ab3d632..a64960c 100644
--- a/include/polarssl/error.h
+++ b/include/polarssl/error.h
@@ -53,6 +53,7 @@
  * MPI       7  0x0002-0x0010
  * GCM       2  0x0012-0x0014
  * BLOWFISH  2  0x0016-0x0018
+ * THREADING 3  0x001A-0x001E
  * AES       2  0x0020-0x0022
  * CAMELLIA  2  0x0024-0x0026
  * XTEA      1  0x0028-0x0028