From: Jean-Paul Pelteret <jppelteret@gmail.com>
Date: Mon, 15 Jun 2020 12:11:57 +0000 (+0200)
Subject: Emit warning when AppleClang < 9.0 is detected
X-Git-Tag: v9.3.0-rc1~1354^2~3
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2ebae6508b7fee2278b03787f194ddc862d670e1;p=dealii.git

Emit warning when AppleClang < 9.0 is detected
---

diff --git a/cmake/setup_compiler_flags_gnu.cmake b/cmake/setup_compiler_flags_gnu.cmake
index 78a54771d9..28b00ed5b3 100644
--- a/cmake/setup_compiler_flags_gnu.cmake
+++ b/cmake/setup_compiler_flags_gnu.cmake
@@ -36,6 +36,18 @@ IF( CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND
     )
 ENDIF()
 
+# Correspondence between AppleClang version and upstream Clang version:
+# https://en.wikipedia.org/wiki/Xcode#Xcode_7.0_-_11.x_(since_Free_On-Device_Development)
+IF (POLICY CMP0025)
+  IF( CMAKE_CXX_COMPILER_ID MATCHES "AppleClang" AND
+      CMAKE_CXX_COMPILER_VERSION VERSION_LESS "9.0" )
+    MESSAGE(WARNING "\n"
+      "deal.II requires support for features of C++14 that are not present in\n"
+      "versions of AppleClang prior to 9.0."
+      )
+  ENDIF()
+ENDIF()
+
 
 ########################
 #                      #
diff --git a/doc/readme.html b/doc/readme.html
index 9ee9842e49..eecdd24ea1 100644
--- a/doc/readme.html
+++ b/doc/readme.html
@@ -63,7 +63,8 @@
     </p>
     <ul>
         <li>GNU/Linux: GCC version 4.9 or later; Clang version 4.0 or later; ICC versions 15 or later</li>
-        <li>Mac OS X: GCC version 4.9 or later; Clang version 4.0 or later. Please see the <a href="https://github.com/dealii/dealii/wiki/MacOSX" target="_top">deal.II Wiki</a> for installation instructions.</li>
+        <li>Mac OS X: GCC version 4.9 or later; Clang version 4.0 or later; <a href="https://en.wikipedia.org/wiki/Xcode#Xcode_7.0_-_11.x_(since_Free_On-Device_Development)">Apple Clang version 9.0</a>  or later. 
+            Please see the <a href="https://github.com/dealii/dealii/wiki/MacOSX" target="_top">deal.II Wiki</a> for installation instructions.</li>
         <li>Windows: experimental support for Visual Studio 2017. Please have a look at the
             <a href="https://github.com/dealii/dealii/wiki/Frequently-Asked-Questions#can-i-use-dealii-on-a-windows-platform">
       FAQ</a> and at the <a href="https://github.com/dealii/dealii/wiki/Windows" target="_top">deal.II Wiki</a> for more information and alternative solutions.</li>