From: Matthias Maier <tamiko@43-1.org>
Date: Thu, 4 Feb 2021 18:46:28 +0000 (-0600)
Subject: CMake: Add a compatibility check for taskflow-3.0 onwards
X-Git-Tag: v9.3.0-rc1~511^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b07ca3ad78c686968888ac68cbc4a785796accd9;p=dealii.git

CMake: Add a compatibility check for taskflow-3.0 onwards
---

diff --git a/cmake/configure/configure_1_taskflow.cmake b/cmake/configure/configure_1_taskflow.cmake
index d4ed1d561b..1951a41a32 100644
--- a/cmake/configure/configure_1_taskflow.cmake
+++ b/cmake/configure/configure_1_taskflow.cmake
@@ -42,6 +42,26 @@ MACRO(FEATURE_TASKFLOW_FIND_EXTERNAL var)
       )
     SET(${var} FALSE)
   ENDIF()
+
+
+  IF(NOT TASKFLOW_VERSION VERSION_LESS "3.0" AND NOT DEAL_II_HAVE_CXX17)
+    # Clear the previously determined version numbers to avoid confusion
+    SET(TASKFLOW_VERSION "bundled")
+    SET(TASKFLOW_VERSION_MAJOR "")
+    SET(TASKFLOW_VERSION_MINOR "")
+
+    MESSAGE(STATUS
+      "The externally provided Taskflow library (version 3.0 onwards)
+      requires C++17 support, which has not been configured."
+      )
+    SET(TASKFLOW_ADDITIONAL_ERROR_STRING
+      "The externally provided Taskflow library (version 3.0 onwards) "
+      "requires C++17 support, but no C++17 support had been detected "
+      "during configuration.\n"
+      "Try to set -DDEAL_II_CXX_FLAGS=\"-std=c++17\" by hand.\n"
+      )
+    SET(${var} FALSE)
+  ENDIF()
 ENDMACRO()