diff --git a/generator/ocaml.ml b/generator/ocaml.ml
index d2a4690d7..05c7456a2 100644
--- a/generator/ocaml.ml
+++ b/generator/ocaml.ml
@@ -132,6 +132,7 @@ val last_errno : t -> int
     which you can use to test the return value of {!Guestfs.last_errno}. *)
 
 module Errno : sig
+  val errno_EINVAL : int
   val errno_ENOTSUP : int
   val errno_EPERM : int
   val errno_ESRCH : int
@@ -286,6 +287,8 @@ external event_to_string : event list -> string
 external last_errno : t -> int = \"ocaml_guestfs_last_errno\"
 
 module Errno = struct
+  external einval : unit -> int = \"ocaml_guestfs_get_EINVAL\" \"noalloc\"
+  let errno_EINVAL = einval ()
   external enotsup : unit -> int = \"ocaml_guestfs_get_ENOTSUP\" \"noalloc\"
   let errno_ENOTSUP = enotsup ()
   external eperm : unit -> int = \"ocaml_guestfs_get_EPERM\" \"noalloc\"
diff --git a/ocaml/guestfs-c.c b/ocaml/guestfs-c.c
index f1a941c09..9603f041a 100644
--- a/ocaml/guestfs-c.c
+++ b/ocaml/guestfs-c.c
@@ -63,6 +63,7 @@ value ocaml_guestfs_set_event_callback (value gv, value closure, value events);
 value ocaml_guestfs_delete_event_callback (value gv, value eh);
 value ocaml_guestfs_event_to_string (value events);
 value ocaml_guestfs_last_errno (value gv);
+value ocaml_guestfs_get_EINVAL (value unitv);
 value ocaml_guestfs_get_ENOTSUP (value unitv);
 value ocaml_guestfs_get_EPERM (value unitv);
 value ocaml_guestfs_get_ESRCH (value unitv);
@@ -442,6 +443,13 @@ ocaml_guestfs_last_errno (value gv)
   CAMLreturn (rv);
 }
 
+/* NB: "noalloc" function. */
+value
+ocaml_guestfs_get_EINVAL (value unitv)
+{
+  return Val_int (EINVAL);
+}
+
 /* NB: "noalloc" function. */
 value
 ocaml_guestfs_get_ENOTSUP (value unitv)