[PATCH v4 3/3] doc: add deprecation marker usage

[Ferruh Yigit <ferruh.yigit@intel.com>]

Define '__rte_deprecated' usage process.

Suggests keeping old API with '__rte_deprecated' marker including
next LTS, they will be removed just after the LTS release.

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: Luca Boccassi <bluca@debian.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
---
Cc: Luca Boccassi <bluca@debian.org>
Cc: Kevin Traynor <ktraynor@redhat.com>
Cc: Yongseok Koh <yskoh@mellanox.com>
Cc: Neil Horman <nhorman@tuxdriver.com>

v2:
* Rephrased as commented

v3:
* changed when to remove the deprecated API. It is now just after
an LTS release, the motivation is to keep changes small in LTS.
Based on techboard discussion:
http://mails.dpdk.org/archives/dev/2019-January/123519.html

v4:
change working around 'active':
s/active/non-experimental/
s/become active/be able to replace old API
---
 doc/guides/contributing/versioning.rst | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/doc/guides/contributing/versioning.rst b/doc/guides/contributing/versioning.rst
index bfc27fbe0..491fae438 100644
--- a/doc/guides/contributing/versioning.rst
+++ b/doc/guides/contributing/versioning.rst
@@ -125,6 +125,15 @@ added to the Release Notes:
   these changes. Binaries using this library built prior to version 2.1 will
   require updating and recompilation.
 
+New API replacing previous one
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If a new API proposed functionally replaces an existing one, when the new API
+becomes non-experimental then the old one is marked with ``__rte_deprecated``.
+Deprecated APIs removed completely just after the next LTS.
+
+Reminder that new API should follow deprecation process to be able to replace old API.
+
 
 Experimental APIs
 -----------------
-- 
2.17.2