Cleanups of cmake build use support.

.travis.yml

@@ -48,11 +48,9 @@ matrix:
   exclude:
     - env: TRAVIS_EMPTY_JOB_WORKAROUND=true
   include:
-    # cmake self-test
-    - env: TEST_CMAKE=TRUE #Only for easier identification in travis web gui
-      os: linux
-
-      # skip all the unneeded steps from the normal unit test jobs
+    # Check CMake project use support.
+    - env: TEST_CMAKE
+      # Skip all the unneeded steps from the normal unit test jobs
       install: true
       before_script: true
       before_cache: true
@@ -60,6 +58,7 @@ matrix:
       after_success: true
       after_failure: true
       after_script: true
+      # Build CMake simple test project that uses Predef.
       script:
         - mkdir __build__ && cd __build__
         - cmake ../test/test_cmake

CMakeLists.txt

@@ -1,9 +1,12 @@
-# Copyright 2018 Mike Dev
+# Copyright Mike Dev 2018
+# Copyright Rene Rivera 2018
 # Distributed under the Boost Software License, Version 1.0.
-# See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt
-#
-# NOTE: CMake support for Boost.Predef is currently experimental at best
-#       and the interface is likely to change in the future
+# See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt
+
+# NOTE:
+#   CMake support for Boost.Predef is currently experimental at best and the
+#   interface is likely to change in the future
 #
 # This file provides mininmal cmake support (no unit-tests,
 # no installation) for integration into a "host" cmake project
@@ -14,13 +17,22 @@
 # on this library. I.e:
 #
 # target_link_libraries( <my-exe/lib> PUBLIC Boost::predef )
-#
 
-cmake_minimum_required( VERSION 3.5 )
+# Only need the basic minimum of project, add_library, and
+# target_include_directories commands.
+cmake_minimum_required( VERSION 3.0 )
+
+# Don't set VERSION, as that's a pita to keep up to date with the version
+# header. And don't set LANGUAGES as we are multi-language and header
+# only, so it's irrelevant.
 project( BoostPredef )
 
+# Simple INTERFACE, and header only, library target.
 add_library( boost_predef INTERFACE )
+
+# The only usage requirement is include dir for consumers.
 target_include_directories( boost_predef INTERFACE include )
 
+# Add an alias to be compatible with consumers that may have used the
+# FindBoost script.
 add_library( Boost::predef ALIAS boost_predef )
-

test/test_cmake/CMakeLists.txt

@@ -1,21 +1,29 @@
-# Copyright 2018 Mike Dev
+# Copyright Mike Dev 2018
+# Copyright Rene Rivera 2018
 # Distributed under the Boost Software License, Version 1.0.
-# See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt
-#
-# NOTE: This does NOT run the unit tests for Boost.Predef.
-#       It only tests, if the CMakeLists.txt file in predef's
-#       root directory works as expected (i.e. it provides the
-#       target Boost::predef which in turn provides the
-#       correct include directory )
+# See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt
 
-cmake_minimum_required( VERSION 3.5 )
+# NOTE:
+#   This does NOT run the unit tests for Boost.Predef.
+#   It only tests, if the CMakeLists.txt file in predef's
+#   root directory works as expected (i.e. it provides the
+#   target Boost::predef which in turn provides the
+#   correct include directory )
+
+# We have very simple cmake requirements we we still require the new style
+# declarative targets.
+cmake_minimum_required( VERSION 3.0 )
 
 project( BoostPredefCMakeSelfTest )
 
-# Process cmake file at root of library and use ${CMAKE_CURRENT_BINARY_DIR}/libs/boost_predef as workspace
+# Process cmake file at root of library and use
+# ${CMAKE_CURRENT_BINARY_DIR}/libs/boost_predef as workspace
 add_subdirectory( ../.. ${CMAKE_CURRENT_BINARY_DIR}/libs/boost_predef )
 
+# The executable just includes a predef header to verify that it's used.
 add_executable( boost_predef_cmake_test_prj main.cpp )
 
+# The executable needs to "use" the Predef "library" to get the usage
+# requirements added to the executable build.
 target_link_libraries( boost_predef_cmake_test_prj Boost::predef )
-

test/test_cmake/main.cpp

@@ -1,7 +1,19 @@
-// Dummy executable, just to make sure
-// that we can find the Boost.predef header files
+/*
+Copyright Mike Dev 2018
+Copyright 2018 Rene Rivera
+Distributed under the Boost Software License, Version 1.0.
+See accompanying file LICENSE_1_0.txt or copy at
+http://www.boost.org/LICENSE_1_0.txt
+*/
+
+/*
+Dummy executable, just to make sure that we can find the Boost.predef header
+files.
+*/
+
 #include <boost/predef.h>
 
-int main() {
-
+int main()
+{
+    return 0;
 }