Binary flag is needed on windows.
diff --git a/Doc/library/mmap.rst b/Doc/library/mmap.rst
index 09ec73b..a6e9bdc 100644
--- a/Doc/library/mmap.rst
+++ b/Doc/library/mmap.rst
@@ -99,10 +99,10 @@
import mmap
# write a simple example file
- with open("hello.txt", "w") as f:
+ with open("hello.txt", "wb") as f:
f.write("Hello Python!\n")
- with open("hello.txt", "r+") as f:
+ with open("hello.txt", "r+b") as f:
# memory-map the file, size 0 means whole file
map = mmap.mmap(f.fileno(), 0)
# read content via standard file methods