(Merge 3.1) Issue #11277: mmap.mmap() calls fcntl(fd, F_FULLFSYNC) on Mac OS X
to get around a mmap bug with sparse files. Patch written by Steffen Daode
Nurpmeso.
diff --git a/Doc/library/mmap.rst b/Doc/library/mmap.rst
index 125b34f..f036a60 100644
--- a/Doc/library/mmap.rst
+++ b/Doc/library/mmap.rst
@@ -94,6 +94,10 @@
defaults to 0. *offset* must be a multiple of the PAGESIZE or
ALLOCATIONGRANULARITY.
+ To ensure validity of the created memory mapping the file specified
+ by the descriptor *fileno* is internally automatically synchronized
+ with physical backing store on Mac OS X and OpenVMS.
+
This example shows a simple way of using :class:`mmap`::
import mmap