Update to C++20

.github/actions/abi-compat/Dockerfile

@@ -1,6 +1,8 @@
 FROM ghcr.io/rse-ops/gcc-ubuntu-20.04:gcc-8.1.0
 
-RUN sudo apt-get -qq update && sudo apt-get install -y --no-install-recommends abigail-tools perl-base binutils libtool pkg-config elfutils libelf-dev
+RUN sudo apt-get -qq update && sudo apt-get install -y --no-install-recommends abigail-tools perl-base binutils libtool pkg-config elfutils libelf-dev python3-pip
+
+RUN sudo pip3 install cmake --upgrade
 
 RUN git clone https://github.com/lvc/vtable-dumper && cd vtable-dumper \
     && sudo make install

.github/workflows/build.yml

@@ -79,8 +79,8 @@ jobs:
             UMPIRE_ENABLE_TOOLS=Off
             UMPIRE_ENABLE_DEVELOPER_BENCHMARKS=On
             UMPIRE_ENABLE_BENCHMARKS=Off
-            BLT_CXX_STD="c++17"
-            CMAKE_CXX_STANDARD=17
+            BLT_CXX_STD="c++20"
+            CMAKE_CXX_STANDARD=20
             CMAKE_BUILD_TYPE=Release
             ${{ matrix.shared.args }}
           run-build: true

CMakeLists.txt

@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier: (MIT)
 ##############################################################################
-cmake_minimum_required(VERSION 3.23)
+cmake_minimum_required(VERSION 3.24.2)
 
 cmake_policy(SET CMP0025 NEW)
 cmake_policy(SET CMP0048 NEW)
@@ -26,33 +26,36 @@ set(UMPIRE_VERSION_RC "")
 
 include(cmake/SetupUmpireOptions.cmake)
 
-# Default to c++17 if not specified by the user.
-set(BLT_CXX_STD "c++17" CACHE STRING "Version of C++ standard")
+# Default to C++20 if not specified by the user.
+set(BLT_CXX_STD "c++20" CACHE STRING "Version of C++ standard")
 
-# If BLT_CXX_STD is set by the user, check that it is at least 17.
+# If BLT_CXX_STD is set by the user, check that it is at least 20.
 if("${BLT_CXX_STD}" STREQUAL "c++98" OR
    "${BLT_CXX_STD}" STREQUAL "c++03" OR
    "${BLT_CXX_STD}" STREQUAL "c++11" OR
-   "${BLT_CXX_STD}" STREQUAL "c++14")
-  message(FATAL_ERROR "Umpire requires a minimum C++ standard of c++17. Please set BLT_CXX_STD accordingly.")
+   "${BLT_CXX_STD}" STREQUAL "c++14" OR
+   "${BLT_CXX_STD}" STREQUAL "c++17")
+  message(FATAL_ERROR "Umpire requires a minimum C++ standard of c++20. Please set BLT_CXX_STD accordingly.")
 endif()
 
-# If CMAKE_CUDA_STANDARD is set by the user, check that it is at least 17.
+# If CMAKE_CUDA_STANDARD is set by the user, check that it is at least 20.
 # If it is not set, it will be set later by BLT to match BLT_CXX_STD.
 if ("${CMAKE_CUDA_STANDARD}" STREQUAL "98" OR
     "${CMAKE_CUDA_STANDARD}" STREQUAL "03" OR
     "${CMAKE_CUDA_STANDARD}" STREQUAL "11" OR
-    "${CMAKE_CUDA_STANDARD}" STREQUAL "14")
-  message(FATAL_ERROR "Umpire requires a minimum CUDA standard of 17. Please set BLT_CXX_STD and/or CMAKE_CUDA_STANDARD accordingly.")
+    "${CMAKE_CUDA_STANDARD}" STREQUAL "14" OR
+    "${CMAKE_CUDA_STANDARD}" STREQUAL "17")
+  message(FATAL_ERROR "Umpire requires a minimum CUDA standard of 20. Please set BLT_CXX_STD and/or CMAKE_CUDA_STANDARD accordingly.")
 endif()
 
-# If CMAKE_HIP_STANDARD is set by the user, check that it is at least 17.
+# If CMAKE_HIP_STANDARD is set by the user, check that it is at least 20.
 # If it is not set, it will be set later by BLT to match BLT_CXX_STD.
 if ("${CMAKE_HIP_STANDARD}" STREQUAL "98" OR
     "${CMAKE_HIP_STANDARD}" STREQUAL "03" OR
     "${CMAKE_HIP_STANDARD}" STREQUAL "11" OR
-    "${CMAKE_HIP_STANDARD}" STREQUAL "14")
-  message(FATAL_ERROR "Umpire requires a minimum HIP standard of 17. Please set BLT_CXX_STD and/or CMAKE_HIP_STANDARD accordingly.")
+    "${CMAKE_HIP_STANDARD}" STREQUAL "14" OR
+    "${CMAKE_HIP_STANDARD}" STREQUAL "17")
+  message(FATAL_ERROR "Umpire requires a minimum HIP standard of 20. Please set BLT_CXX_STD and/or CMAKE_HIP_STANDARD accordingly.")
 endif()
 
 if (UMPIRE_ENABLE_SYCL)
@@ -174,16 +177,6 @@ include(cmake/SetupCMakeBasics.cmake)
 include(cmake/SetupCompilerFlags.cmake)
 include(cmake/SetupUmpireThirdParty.cmake)
 
-if (WIN32)
-  if ((NOT UMPIRE_ENABLE_FILESYSTEM) OR (CMAKE_CXX_STANDARD LESS 17))
-    message(FATAL_ERROR "\
-    Windows builds require the FileSystem to be enabled \
-    and the C/C++ standard to be set to 17 or higher. \
-    Please re-configure with UMPIRE_ENABLE_FILESYSTEM=ON, \
-    with BLT_CXX_STD=c++17 or greater.")
-  endif()
-endif()
-
 add_subdirectory(src)
 
 configure_package_config_file(

examples/resource_aware_pool_example.cpp

@@ -53,7 +53,7 @@ __device__ void sleep(clock_value_t sleep_cycles)
 __global__ void do_sleep()
 {
   // sleep - works still at 1000, so keeping it at 100k
-  sleep(10000000);
+  sleep((clock_value_t)10000000);
 }
 #endif
 

src/tpl/umpire/CLI11/CLI11.hpp

@@ -6431,14 +6431,14 @@ struct AppFriend {
     /// Wrap _parse_short, perfectly forward arguments and return
     template <typename... Args>
     static auto parse_arg(App *app, Args &&... args) ->
-        typename std::result_of<decltype (&App::_parse_arg)(App, Args...)>::type {
+        typename std::invoke_result<decltype (&App::_parse_arg), App, Args...>::type {
         return app->_parse_arg(std::forward<Args>(args)...);
     }
 
     /// Wrap _parse_subcommand, perfectly forward arguments and return
     template <typename... Args>
     static auto parse_subcommand(App *app, Args &&... args) ->
-        typename std::result_of<decltype (&App::_parse_subcommand)(App, Args...)>::type {
+        typename std::invoke_result<decltype (&App::_parse_subcommand), App, Args...>::type {
         return app->_parse_subcommand(std::forward<Args>(args)...);
     }
     /// Wrap the fallthrough parent function to make sure that is working correctly