Test in 32-bit mode on linux (#263)

Author: jeremy-rifkin

.github/workflows/ci.yml

@@ -678,6 +678,35 @@ jobs:
            ninja
            ./unittest_module
 
+  unittest-linux-32-bit:
+    runs-on: ubuntu-24.04
+    needs: unittest-linux
+    strategy:
+      fail-fast: false
+      matrix:
+        compiler: [g++-10, clang++-18]
+    steps:
+    - uses: actions/checkout@v4
+    - name: dependencies
+      run: |
+           sudo apt install gcc-10 g++-10 libgcc-10-dev clang-19 clang-tools-19 ninja-build gcc-multilib g++-multilib g++-10-multilib
+    - name: build and test
+      run: |
+           mkdir build
+           cd build
+           cmake .. \
+             -GNinja \
+             -DCMAKE_BUILD_TYPE=Debug \
+             -DCMAKE_CXX_COMPILER=${{matrix.compiler}} \
+             -DCMAKE_C_COMPILER=${{matrix.compiler == 'clang++-18' && 'clang' || 'gcc'}} \
+             -DCPPTRACE_WERROR_BUILD=On \
+             -DCPPTRACE_STD_FORMAT=Off \
+             -DCPPTRACE_BUILD_TESTING=On \
+             -DCMAKE_C_FLAGS=-m32 \
+             -DCMAKE_CXX_FLAGS=-m32
+           ninja
+           ./unittest_module
+
   unittest-windows-32-bit:
     runs-on: windows-2022
     needs: unittest-windows

src/ctrace.cpp

@@ -342,7 +342,7 @@ extern "C" {
         const auto green   = use_color ? ESC "32m" : "";
         const auto yellow  = use_color ? ESC "33m" : "";
         const auto blue    = use_color ? ESC "34m" : "";
-        const auto frame_number_width = cpptrace::detail::n_digits(unsigned(trace->count - 1));
+        const auto frame_number_width = cpptrace::detail::n_digits(cpptrace::detail::to<unsigned>(trace->count - 1));
         ctrace_stacktrace_frame* frames = trace->frames;
         for(std::size_t i = 0; i < trace->count; ++i) {
             static constexpr auto ptr_len = 2 * sizeof(cpptrace::frame_ptr);