From f995e594231cb4796ed7ce0f3ee1bd437f03575d Mon Sep 17 00:00:00 2001
From: Kirill Kirilenko <kirill@ultracoder.org>
Date: Sat, 26 Nov 2016 03:01:12 +0300
Subject: [PATCH] Added CMake function RequireCXX14(). Fixed double compiler
 flags.

---
 CMakeLists.txt           | 25 ++-----------------------
 cmake/RequireCXX14.cmake | 26 ++++++++++++++++++++++++++
 src/CMakeLists.txt       |  3 +++
 tests/CMakeLists.txt     |  3 +++
 4 files changed, 34 insertions(+), 23 deletions(-)
 create mode 100644 cmake/RequireCXX14.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c116f48..7832f08 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,34 +1,13 @@
 cmake_minimum_required(VERSION 2.8)
 
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} cmake)
+
 if (NOT DEFINED CMAKE_BUILD_TYPE)
   set(CMAKE_BUILD_TYPE Release CACHE STRING "Type of build (Release, Debug, RelWithDebInfo, MinSizeRel)")
 endif()
 
 project(telebotxx CXX)
 
-message(STATUS "Checking compiler flags for C++14 support.")
-# Set C++14 support flags for various compilers
-include(CheckCXXCompilerFlag)
-check_cxx_compiler_flag("-std=c++14" COMPILER_SUPPORTS_CXX14)
-check_cxx_compiler_flag("-std=c++1y" COMPILER_SUPPORTS_CXX1Y)
-if(COMPILER_SUPPORTS_CXX14)
-  message(STATUS "C++14 is supported.")
-  if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14 -stdlib=libc++")
-  else()
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14")
-  endif()
-elseif(COMPILER_SUPPORTS_CXX1Y)
-  message(STATUS "C++1y is supported.")
-  if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++1y -stdlib=libc++")
-  else()
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++1y")
-  endif()
-else()
-  message(STATUS "The compiler ${CMAKE_CXX_COMPILER} has no C++14 support. Please use a different C++ compiler.")
-endif()
-
 option (TELEBOTXX_BUILD_TESTS   "Build unit tests using Boost.Test" ON)
 option (TELEBOTXX_GENERATE_DOC  "Generate API documentation with Doxygen" ON)
 
diff --git a/cmake/RequireCXX14.cmake b/cmake/RequireCXX14.cmake
new file mode 100644
index 0000000..6d4d575
--- /dev/null
+++ b/cmake/RequireCXX14.cmake
@@ -0,0 +1,26 @@
+cmake_minimum_required(VERSION 2.8)
+
+function(RequireCXX14)
+  message(STATUS "Checking compiler flags for C++14 support.")
+  # Set C++14 support flags for various compilers
+  include(CheckCXXCompilerFlag)
+  check_cxx_compiler_flag("-std=c++14" COMPILER_SUPPORTS_CXX14)
+  check_cxx_compiler_flag("-std=c++1y" COMPILER_SUPPORTS_CXX1Y)
+  if(COMPILER_SUPPORTS_CXX14)
+    message(STATUS "C++14 is supported.")
+    if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14 -stdlib=libc++" PARENT_SCOPE)
+    else()
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14" PARENT_SCOPE)
+    endif()
+  elseif(COMPILER_SUPPORTS_CXX1Y)
+    message(STATUS "C++1y is supported.")
+    if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++1y -stdlib=libc++" PARENT_SCOPE)
+    else()
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++1y" PARENT_SCOPE)
+    endif()
+  else()
+    message(ERROR "The compiler ${CMAKE_CXX_COMPILER} has no C++14 support. Please use a different C++ compiler.")
+  endif()
+endfunction()
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ef3bcdb..962f235 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -2,6 +2,9 @@ cmake_minimum_required(VERSION 2.8)
 
 message(STATUS "Configuring telebotxx")
 
+include(${CMAKE_SOURCE_DIR}/cmake/RequireCXX14.cmake)
+RequireCXX14()
+
 find_package(Boost REQUIRED)
 include_directories(${Boost_INCLUDE_DIRS})
 
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 938f666..6e54dbe 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -5,6 +5,9 @@ endif()
 
 message(STATUS "Configuring telebotxx-test")
 
+include(${CMAKE_SOURCE_DIR}/cmake/RequireCXX14.cmake)
+RequireCXX14()
+
 add_definitions(-DBOOST_TEST_DYN_LINK)
 find_package(Boost REQUIRED COMPONENTS unit_test_framework system)
 include_directories(${Boost_INCLUDE_DIRS})