Refer to strftime(3) manpage for platform specific format codes.
Suggested by Skip Montanaro on docs@.
diff --git a/Doc/library/datetime.rst b/Doc/library/datetime.rst
index 4e922f0..0de7391 100644
--- a/Doc/library/datetime.rst
+++ b/Doc/library/datetime.rst
@@ -1603,7 +1603,8 @@
The full set of format codes supported varies across platforms, because Python
calls the platform C library's :func:`strftime` function, and platform
-variations are common.
+variations are common. To see the full set of format codes supported on your
+platform, consult the :manpage:`strftime(3)` documentation.
The following is a list of all the format codes that the C standard (1989
version) requires, and these work on all platforms with a standard C
diff --git a/Doc/library/time.rst b/Doc/library/time.rst
index a4de69f..1129ea4 100644
--- a/Doc/library/time.rst
+++ b/Doc/library/time.rst
@@ -350,8 +350,10 @@
>>> strftime("%a, %d %b %Y %H:%M:%S +0000", gmtime())
'Thu, 28 Jun 2001 14:17:15 +0000'
- Additional directives may be supported on certain platforms, but only the ones
- listed here have a meaning standardized by ANSI C.
+ Additional directives may be supported on certain platforms, but only the
+ ones listed here have a meaning standardized by ANSI C. To see the full set
+ of format codes supported on your platform, consult the :manpage:`strftime(3)`
+ documentation.
On some platforms, an optional field width and precision specification can
immediately follow the initial ``'%'`` of a directive in the following order;