Merge pull request #202 from fastfloat/cxx20ci

Adding C++20 tests in CI.

Author: lemire

.github/workflows/ubuntu20-cxx20.yml

@@ -13,7 +13,7 @@ jobs:
         run: |
           mkdir build &&
           cd build &&
-          cmake -DCMAKE_CXX_STANDARD=20 -DFASTFLOAT_TEST=ON -DCMAKE_INSTALL_PREFIX:PATH=destination ..  &&
+          cmake -DFASTFLOAT_CXX_STANDARD=20 -DFASTFLOAT_TEST=ON -DCMAKE_INSTALL_PREFIX:PATH=destination ..  &&
           cmake --build .   &&
           ctest --output-on-failure  &&
           cmake --install .

.github/workflows/ubuntu22-clang.yml

@@ -20,6 +20,6 @@ jobs:
         run: |
           mkdir build20 &&
           cd build20 &&
-          CXX=clang++-14 cmake -DFASTFLOAT_CONSTEXPR_TESTS=ON -DCMAKE_CXX_STANDARD=20 -DFASTFLOAT_TEST=ON  ..  &&
+          CXX=clang++-14 cmake -DFASTFLOAT_CONSTEXPR_TESTS=ON -DFASTFLOAT_CXX_STANDARD=20 -DFASTFLOAT_TEST=ON  ..  &&
           cmake --build .   &&
           ctest --output-on-failure

.github/workflows/ubuntu22-gcc12.yml

@@ -18,6 +18,6 @@ jobs:
         run: |
           mkdir build20 &&
           cd build20 &&
-          CXX=g++-12 CXXFLAGS=-Werror cmake -DFASTFLOAT_CONSTEXPR_TESTS=ON -DCMAKE_CXX_STANDARD=20 -DFASTFLOAT_TEST=ON  ..  &&
+          CXX=g++-12 CXXFLAGS=-Werror cmake -DFASTFLOAT_CONSTEXPR_TESTS=ON -DFASTFLOAT_CXX_STANDARD=20 -DFASTFLOAT_TEST=ON  ..  &&
           cmake --build .   &&
           ctest --output-on-failure

.github/workflows/vs17-cxx20.yml

@@ -20,7 +20,7 @@ jobs:
       - name: configure
         run: >-
           cmake -S . -B build -G "${{matrix.gen}}" -A ${{matrix.arch}}
-          -DCMAKE_CXX_STANDARD=20
+          -DFASTFLOAT_CXX_STANDARD=20
           -DFASTFLOAT_TEST=ON
           -DFASTFLOAT_CONSTEXPR_TESTS=ON
           -DCMAKE_INSTALL_PREFIX:PATH=destination

tests/installation_tests/find/CMakeLists.txt

@@ -2,6 +2,8 @@ cmake_minimum_required(VERSION 3.15)
 
 project(test_install VERSION 0.1.0 LANGUAGES CXX)
 
+set(FASTFLOAT_CXX_STANDARD 17 CACHE STRING "the C++ standard to use for fastfloat")
+set(CMAKE_CXX_STANDARD ${FASTFLOAT_CXX_STANDARD})
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 if(MSVC_VERSION GREATER 1910)