If connected to a terminal, set stderr to be unbuffered

ocaml · Jul 24, 2021 · 972eae0 · 972eae0
1 parent 456afd1
commit 972eae0
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/stdlib/stdlib.ml b/stdlib/stdlib.ml
@@ -311,10 +311,17 @@ external open_descriptor_out : int -> out_channel
                              = "caml_ml_open_descriptor_out"
 external open_descriptor_in : int -> in_channel = "caml_ml_open_descriptor_in"
 
+external set_channel_unbuffered : out_channel -> unit = "caml_ml_set_channel_unbuffered"
+
 let stdin = open_descriptor_in 0
 let stdout = open_descriptor_out 1
 let stderr = open_descriptor_out 2
 
+external isatty : out_channel -> bool = "caml_sys_isatty"
+
+let () =
+  if isatty stderr then set_channel_unbuffered stderr
+
 (* General output functions *)
 
 type open_flag =