diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0098e752..e01a3a3a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,213 +1,85 @@
-name: ci
+name: nix_gcc_clang
 
 on: [push, pull_request]
 
 jobs:
-#  # -----------------------------------------------------------------------
-#  # Linux build matrix
-#  # -----------------------------------------------------------------------
-#  build_linux:
-#    runs-on: ubuntu-latest
-#    defaults:
-#      run:
-#        shell: bash
-#    strategy:
-#      fail-fast: false
-#      matrix:
-#        config:
-#          - { compiler: gcc, version: 7, build_type: Release, cppstd: 11 }
-#          - { compiler: gcc, version: 9, build_type: Release, cppstd: 17 }
-#          - { compiler: gcc, version: 11, build_type: Debug, cppstd: 20 }
-#          - { compiler: gcc, version: 12, build_type: Release, cppstd: 20 }
-#          - { compiler: clang, version: 12, build_type: Debug, cppstd: 17, asan: OFF }
-#          - { compiler: clang, version: 15, build_type: Release, cppstd: 20, asan: OFF }
-#    container:
-#      image: ${{ matrix.config.compiler == 'clang' && 'teeks99/clang-ubuntu' || matrix.config.compiler }}:${{ matrix.config.version }}
-#    name: "${{ matrix.config.compiler}} ${{ matrix.config.version }} (C++${{ matrix.config.cppstd }}, ${{ matrix.config.build_type }})"
-#    steps:
-#      - uses: actions/checkout@main
-#      - name: Setup
-#        run: |
-#          apt-get update
-#          apt-get install -y curl git pkg-config libsystemd-dev
-#          CMAKE_VERSION="3.24.2"
-#          curl -sSL https://github.com/Kitware/CMake/releases/download/v${CMAKE_VERSION}/cmake-${CMAKE_VERSION}-linux-x86_64.sh -o install-cmake.sh
-#          chmod +x install-cmake.sh
-#          ./install-cmake.sh --prefix=/usr/local --skip-license
-#      - name: Setup Compiler
-#        if: matrix.config.compiler == 'clang'
-#        run: |
-#          if [[ "${{ matrix.config.version }}" -ge 4 ]]; then
-#            scripts/ci_setup_clang.sh "${{ matrix.config.version }}"
-#            echo "CXXFLAGS=-stdlib=libc++" >> $GITHUB_ENV
-#          fi
-#          echo "CC=clang-${{ matrix.config.version }}" >> $GITHUB_ENV
-#          echo "CXX=clang++-${{ matrix.config.version }}" >> $GITHUB_ENV
-#      - name: Build
-#        run: |
-#          mkdir -p build && cd build
-#          cmake .. \
-#            -DCMAKE_BUILD_TYPE=${{ matrix.config.build_type }} \
-#            -DCMAKE_CXX_STANDARD=${{ matrix.config.cppstd }} \
-#            -DSPDLOG_BUILD_EXAMPLE=${{ matrix.config.examples || 'ON' }} \
-#            -DSPDLOG_BUILD_EXAMPLE_HO=${{ matrix.config.examples || 'ON' }} \
-#            -DSPDLOG_BUILD_WARNINGS=ON \
-#            -DSPDLOG_BUILD_BENCH=OFF \
-#            -DSPDLOG_BUILD_TESTS=ON \
-#            -DSPDLOG_BUILD_TESTS_HO=OFF \
-#            -DSPDLOG_SANITIZE_ADDRESS=${{ matrix.config.asan || 'ON' }}
-#          make -j2
-#          ctest -j2 --output-on-failure
-#
-#  # -----------------------------------------------------------------------
-#  # OS X build matrix
-#  # -----------------------------------------------------------------------
-#  build_osx:
-#    runs-on: macOS-latest
-#    name: "OS X Clang (C++11, Release)"
-#    steps:
-#      - uses: actions/checkout@main
-#      - name: Build
-#        run: |
-#          mkdir -p build && cd build
-#          cmake .. \
-#            -DCMAKE_BUILD_TYPE=Release \
-#            -DCMAKE_CXX_STANDARD=11 \
-#            -DSPDLOG_BUILD_EXAMPLE=ON \
-#            -DSPDLOG_BUILD_EXAMPLE_HO=ON \
-#            -DSPDLOG_BUILD_WARNINGS=ON \
-#            -DSPDLOG_BUILD_BENCH=OFF \
-#            -DSPDLOG_BUILD_TESTS=ON \
-#            -DSPDLOG_BUILD_TESTS_HO=OFF \
-#            -DSPDLOG_SANITIZE_ADDRESS=OFF
-#          make -j2
-#          ctest -j2 --output-on-failure
+  # -----------------------------------------------------------------------
+  # Linux build matrix
+  # -----------------------------------------------------------------------
+  build_linux:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    strategy:
+      fail-fast: false
+      matrix:
+        config:
+          - { compiler: gcc, version: 7, build_type: Release, cppstd: 11 }
+          - { compiler: gcc, version: 9, build_type: Release, cppstd: 17 }
+          - { compiler: gcc, version: 11, build_type: Debug, cppstd: 20 }
+          - { compiler: gcc, version: 12, build_type: Release, cppstd: 20 }
+          - { compiler: clang, version: 12, build_type: Debug, cppstd: 17, asan: OFF }
+          - { compiler: clang, version: 15, build_type: Release, cppstd: 20, asan: OFF }
+    container:
+      image: ${{ matrix.config.compiler == 'clang' && 'teeks99/clang-ubuntu' || matrix.config.compiler }}:${{ matrix.config.version }}
+    name: "${{ matrix.config.compiler}} ${{ matrix.config.version }} (C++${{ matrix.config.cppstd }}, ${{ matrix.config.build_type }})"
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup
+        run: |
+          apt-get update
+          apt-get install -y curl git pkg-config libsystemd-dev
+          CMAKE_VERSION="3.24.2"
+          curl -sSL https://github.com/Kitware/CMake/releases/download/v${CMAKE_VERSION}/cmake-${CMAKE_VERSION}-linux-x86_64.sh -o install-cmake.sh
+          chmod +x install-cmake.sh
+          ./install-cmake.sh --prefix=/usr/local --skip-license
+      - name: Setup Compiler
+        if: matrix.config.compiler == 'clang'
+        run: |
+          if [[ "${{ matrix.config.version }}" -ge 4 ]]; then
+            scripts/ci_setup_clang.sh "${{ matrix.config.version }}"
+            echo "CXXFLAGS=-stdlib=libc++" >> $GITHUB_ENV
+          fi
+          echo "CC=clang-${{ matrix.config.version }}" >> $GITHUB_ENV
+          echo "CXX=clang++-${{ matrix.config.version }}" >> $GITHUB_ENV
+      - name: Build
+        run: |
+          mkdir -p build && cd build
+          cmake .. \
+            -DCMAKE_BUILD_TYPE=${{ matrix.config.build_type }} \
+            -DCMAKE_CXX_STANDARD=${{ matrix.config.cppstd }} \
+            -DSPDLOG_BUILD_EXAMPLE=${{ matrix.config.examples || 'ON' }} \
+            -DSPDLOG_BUILD_EXAMPLE_HO=${{ matrix.config.examples || 'ON' }} \
+            -DSPDLOG_BUILD_WARNINGS=ON \
+            -DSPDLOG_BUILD_BENCH=OFF \
+            -DSPDLOG_BUILD_TESTS=ON \
+            -DSPDLOG_BUILD_TESTS_HO=OFF \
+            -DSPDLOG_SANITIZE_ADDRESS=${{ matrix.config.asan || 'ON' }}
+          make -j2
+          ctest -j2 --output-on-failure
 
   # -----------------------------------------------------------------------
-  # Windows build matrix
+  # OS X build matrix
   # -----------------------------------------------------------------------
-#  build_windows:
-#    runs-on: windows-latest
-#    strategy:
-#      fail-fast: true
-#      matrix:
-#        config:
-#          - GENERATOR: "Visual Studio 17 2022"
-#            BUILD_TYPE: Release
-#            BUILD_SHARED: 'ON'
-#            FATAL_ERRORS: 'ON'
-#            WCHAR: 'OFF'
-#            WCHAR_FILES: 'OFF'
-#            BUILD_EXAMPLE: 'OFF'
-#            USE_STD_FORMAT: 'ON'
-#            CXX_STANDARD: 20
-#          - GENERATOR: "Visual Studio 17 2022"
-#            BUILD_TYPE: Release
-#            BUILD_SHARED: 'ON'
-#            FATAL_ERRORS: 'ON'
-#            WCHAR: 'ON'
-#            WCHAR_FILES: 'ON'
-#            BUILD_EXAMPLE: 'OFF'
-#            USE_STD_FORMAT: 'ON'
-#            CXX_STANDARD: 20
-#          - GENERATOR: "Visual Studio 17 2022"
-#            BUILD_TYPE: Release
-#            BUILD_SHARED: 'ON'
-#            FATAL_ERRORS: 'ON'
-#            WCHAR: 'OFF'
-#            WCHAR_FILES: 'OFF'
-#            BUILD_EXAMPLE: 'ON'
-#            USE_STD_FORMAT: 'OFF'
-#            CXX_STANDARD: 17
-#
-#    steps:
-#      - name: Checkout code
-#        uses: actions/checkout@v4
-#
-#      - name: CMake ${{ matrix.config.GENERATOR }} CXX=${{matrix.config.CXX_STANDARD}} WCHAR=${{matrix.config.WCHAR_FILES}} STD_FORMAT=${{matrix.config.USE_STD_FORMAT}}
-#        shell: pwsh
-#        run: |
-#          mkdir build
-#          cd build
-#          cmake -G "${{ matrix.config.GENERATOR }}"  -A x64 `
-#            -D CMAKE_BUILD_TYPE=${{ matrix.config.BUILD_TYPE }} `
-#            -D BUILD_SHARED_LIBS=${{ matrix.config.BUILD_SHARED }} `
-#            -D SPDLOG_WCHAR_SUPPORT=${{ matrix.config.WCHAR }} `
-#            -D SPDLOG_WCHAR_FILENAMES=${{ matrix.config.WCHAR_FILES }} `
-#            -D SPDLOG_BUILD_EXAMPLE=${{ matrix.config.BUILD_EXAMPLE }} `
-#            -D SPDLOG_BUILD_EXAMPLE_HO=${{ matrix.config.BUILD_EXAMPLE }} `
-#            -D SPDLOG_BUILD_TESTS=ON `
-#            -D SPDLOG_BUILD_TESTS_HO=OFF `
-#            -D SPDLOG_BUILD_WARNINGS=${{ matrix.config.FATAL_ERRORS }} `
-#            -D SPDLOG_USE_STD_FORMAT=${{ matrix.config.USE_STD_FORMAT }} `
-#            -D CMAKE_CXX_STANDARD=${{ matrix.config.CXX_STANDARD }} ..
-#
-#      - name: Build
-#        shell: pwsh
-#        run: |
-#          cd build
-#          cmake --build  . --parallel --config ${{ matrix.config.BUILD_TYPE }}
-#
-#      - name: Run Tests
-#        shell: pwsh
-#        env:
-#          PATH: ${{ env.PATH }};${{ github.workspace }}\build\_deps\catch2-build\src\${{ matrix.config.BUILD_TYPE }};${{ github.workspace }}\build\${{ matrix.config.BUILD_TYPE }}
-#        run: |
-#          build\tests\${{ matrix.config.BUILD_TYPE }}\spdlog-utests.exe
-#
-# # -----------------------------------------------------------------------
-#  # Windows build matrix
-#  # -----------------------------------------------------------------------
-#  build_windos-2019:
-#    runs-on: windows-2019
-#    strategy:
-#      fail-fast: true
-#      matrix:
-#        config:
-#          - GENERATOR: "Visual Studio 16 2019"
-#            BUILD_TYPE: Release
-#            BUILD_SHARED: 'ON'
-#            FATAL_ERRORS: 'ON'
-#            WCHAR: 'OFF'
-#            WCHAR_FILES: 'OFF'
-#            BUILD_EXAMPLE: 'ON'
-#            USE_STD_FORMAT: 'OFF'
-#            CXX_STANDARD: 17
-#
-#    steps:
-#      - name: Checkout code
-#        uses: actions/checkout@v4
-#
-#      - name: CMake ${{ matrix.config.GENERATOR }} CXX=${{matrix.config.CXX_STANDARD}} WCHAR=${{matrix.config.WCHAR_FILES}} STD_FORMAT=${{matrix.config.USE_STD_FORMAT}}
-#        shell: pwsh
-#        run: |
-#          mkdir build
-#          cd build
-#          cmake -G "${{ matrix.config.GENERATOR }}"  -A x64 `
-#            -D CMAKE_BUILD_TYPE=${{ matrix.config.BUILD_TYPE }} `
-#            -D BUILD_SHARED_LIBS=${{ matrix.config.BUILD_SHARED }} `
-#            -D SPDLOG_WCHAR_SUPPORT=${{ matrix.config.WCHAR }} `
-#            -D SPDLOG_WCHAR_FILENAMES=${{ matrix.config.WCHAR_FILES }} `
-#            -D SPDLOG_BUILD_EXAMPLE=${{ matrix.config.BUILD_EXAMPLE }} `
-#            -D SPDLOG_BUILD_EXAMPLE_HO=${{ matrix.config.BUILD_EXAMPLE }} `
-#            -D SPDLOG_BUILD_TESTS=ON `
-#            -D SPDLOG_BUILD_TESTS_HO=OFF `
-#            -D SPDLOG_BUILD_WARNINGS=${{ matrix.config.FATAL_ERRORS }} `
-#            -D SPDLOG_USE_STD_FORMAT=${{ matrix.config.USE_STD_FORMAT }} `
-#            -D CMAKE_CXX_STANDARD=${{ matrix.config.CXX_STANDARD }} ..
-#
-#      - name: Build
-#        shell: pwsh
-#        run: |
-#          cd build
-#          cmake --build  . --parallel --config ${{ matrix.config.BUILD_TYPE }}
-#
-#      - name: Run Tests
-#        shell: pwsh
-#        env:
-#          PATH: ${{ env.PATH }};${{ github.workspace }}\build\_deps\catch2-build\src\${{ matrix.config.BUILD_TYPE }};${{ github.workspace }}\build\${{ matrix.config.BUILD_TYPE }}
-#        run: |
-#          build\tests\${{ matrix.config.BUILD_TYPE }}\spdlog-utests.exe
-#
-#
-#
+  build_osx:
+    runs-on: macOS-latest
+    name: "OS X Clang (C++11, Release)"
+    steps:
+      - uses: actions/checkout@v4
+      - name: Build
+        run: |
+          mkdir -p build && cd build
+          cmake .. \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_CXX_STANDARD=11 \
+            -DSPDLOG_BUILD_EXAMPLE=ON \
+            -DSPDLOG_BUILD_EXAMPLE_HO=ON \
+            -DSPDLOG_BUILD_WARNINGS=ON \
+            -DSPDLOG_BUILD_BENCH=OFF \
+            -DSPDLOG_BUILD_TESTS=ON \
+            -DSPDLOG_BUILD_TESTS_HO=OFF \
+            -DSPDLOG_SANITIZE_ADDRESS=OFF
+          make -j2
+          ctest -j2 --output-on-failure
+