diff --git a/hgext/logtoprocess.py b/hgext/logtoprocess.py
--- a/hgext/logtoprocess.py
+++ b/hgext/logtoprocess.py
@@ -36,11 +36,13 @@
 
 import itertools
 import os
-import platform
 import subprocess
 import sys
 
-from mercurial import encoding
+from mercurial import (
+    encoding,
+    pycompat,
+)
 
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
@@ -49,7 +51,7 @@
 testedwith = 'ships-with-hg-core'
 
 def uisetup(ui):
-    if platform.system() == 'Windows':
+    if pycompat.osname == 'nt':
         # no fork on Windows, but we can create a detached process
         # https://msdn.microsoft.com/en-us/library/windows/desktop/ms684863.aspx
         # No stdlib constant exists for this value