From 6d50d0197a50680466c075feeda338b3b9418e05 Mon Sep 17 00:00:00 2001 From: Stephen Kelly Date: Fri, 18 Oct 2013 19:22:09 +0200 Subject: [PATCH] Help: Add introduction section to cmake-policies manual Explain the concept behind policies. --- Help/manual/cmake-policies.7.rst | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/Help/manual/cmake-policies.7.rst b/Help/manual/cmake-policies.7.rst index 658620f8e..4fcc90b19 100644 --- a/Help/manual/cmake-policies.7.rst +++ b/Help/manual/cmake-policies.7.rst @@ -5,6 +5,26 @@ cmake-policies(7) .. contents:: +Introduction +============ + +Policies in CMake are used to preserve backward compatible behavior +across multiple releases. When a new policy is introduced, newer CMake +versions will begin to warn about the backward compatible behavior. It +is possible to disable the warning by explicitly requesting the OLD, or +backward compatible behavior using the :command:`cmake_policy` command. +It is also possible to request NEW, or non-backward compatible behavior +for a policy, also avoiding the warning. + +The :command:`cmake_minimum_required` command does more than report an +error if a too-old version of CMake is used to build a project. It +also sets all policies introduced in that CMake version or earlier to +NEW behavior. + +The :variable:`CMAKE_MINIMUM_REQUIRED_VERSION` variable may also be used +to determine whether to report an error on use of deprecated macros or +functions. + All Policies ============