commit ff5d21331ec6cefec6ba5b78d256d8dbcd67a069
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Sun Mar 11 11:42:37 2018 -0700
committer Antoine Pitrou <pitrou@free.fr> Sun Mar 11 19:42:37 2018 +0100
tree d4a2a35b1b17721171f87c3b5977246c5cb7173e
parent 04aadf23eac51fec2e436c5960c1362bbb7d03de

bpo-31804: Fix multiprocessing.Process with broken standard streams (GH-6079) (GH-6080)

In some conditions the standard streams will be None or closed in the child process (for example if using "pythonw" instead of "python" on Windows).  Avoid failing with a non-0 exit code in those conditions.

Report and initial patch by poxthegreat.
(cherry picked from commit e756f66c83786ee82f5f7d45931ae50a6931dd7f)

Co-authored-by: Antoine Pitrou <pitrou@free.fr>

Lib/multiprocessing/util.py

diff --git a/Lib/multiprocessing/util.py b/Lib/multiprocessing/util.py
index f0827f0..0c4eb24 100644
--- a/Lib/multiprocessing/util.py
+++ b/Lib/multiprocessing/util.py
@@ -392,6 +392,20 @@
         pass
 
 #
+# Flush standard streams, if any
+#
+
+def _flush_std_streams():
+    try:
+        sys.stdout.flush()
+    except (AttributeError, ValueError):
+        pass
+    try:
+        sys.stderr.flush()
+    except (AttributeError, ValueError):
+        pass
+
+#
 # Start a program with only specified fds kept open
 #