1 files changed, 10 insertions, 0 deletions
diff --git a/clib/cThread.ml b/clib/cThread.ml
index 0b7955aa28..9e0319e8f8 100644
--- a/clib/cThread.ml
+++ b/clib/cThread.ml
@@ -97,3 +97,13 @@ let thread_friendly_input_value ic =
     end
   with Unix.Unix_error _ | Sys_error _ -> raise End_of_file
 
+(* On the ocaml runtime used in some opam-for-windows version the
+ * [Thread.sigmask] API raises Invalid_argument "not implemented",
+ * hence we protect the call and turn the exception into a no-op *)
+let protect_sigalrm f x =
+  begin try ignore(Thread.sigmask Unix.SIG_BLOCK [Sys.sigalrm])
+  with Invalid_argument _ -> () end;
+  f x
+
+let create f x =
+  Thread.create (protect_sigalrm f) x