Add a portability workflow beside the existing matrix

.github/workflows/portability.yml

@@ -0,0 +1,137 @@
+name: Portability
+
+# Dimensions cmake.yml does not reach: capability paths, 32-bit, non-x86, BSD.
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+
+  capability-paths:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: fork instead of posix_spawn
+            defs: -DSUBPROCESS_SPAWN_VIA_FORK=1
+          - name: no chdir file action, no exec error reporting
+            defs: -DSUBPROCESS_HAVE_CWD=0 -DSUBPROCESS_SPAWN_REPORTS_EXEC_ERRORS=0
+          - name: no chdir file action only
+            defs: -DSUBPROCESS_HAVE_CWD=0
+    name: ${{ matrix.name }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Build and test
+        run: |
+          cmake -S test -B build \
+            -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+            -DCMAKE_C_FLAGS="${{ matrix.defs }}" \
+            -DCMAKE_CXX_FLAGS="${{ matrix.defs }}"
+          cmake --build build -j
+          ctest --test-dir build --output-on-failure
+
+  linux-32-bit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install multilib
+        run: sudo apt-get update && sudo apt-get install -y gcc-multilib g++-multilib
+      - name: Build and test
+        run: |
+          cmake -S test -B build \
+            -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+            -DCMAKE_C_FLAGS=-m32 \
+            -DCMAKE_CXX_FLAGS=-m32 \
+            -DCMAKE_EXE_LINKER_FLAGS=-m32
+          cmake --build build -j
+          ctest --test-dir build --output-on-failure
+
+  windows-x86:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v4
+      - run: cmake -S test -B build -A Win32
+      - run: cmake --build build --config RelWithDebInfo
+      - run: ctest --test-dir build -C RelWithDebInfo --output-on-failure
+
+  musl:
+    runs-on: ubuntu-latest
+    container: alpine:3
+    steps:
+      - name: Install toolchain
+        run: apk add --no-cache gcc g++ musl-dev cmake make linux-headers git
+      - uses: actions/checkout@v4
+      - name: Build and test
+        run: |
+          cmake -S test -B build -DCMAKE_BUILD_TYPE=RelWithDebInfo
+          cmake --build build -j
+          ctest --test-dir build --output-on-failure
+
+  # Builds everything, runs only *divzero: qemu-user does not propagate the
+  # errno posix_spawn reports a failed exec with, so the rest fails here on
+  # every architecture regardless of target.
+  foreign-arch:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        arch: [ppc64le, riscv64, s390x, armv7]
+    name: linux ${{ matrix.arch }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: uraimo/run-on-arch-action@v3
+        with:
+          arch: ${{ matrix.arch }}
+          distro: ubuntu_latest
+          install: |
+            apt-get update -q
+            apt-get install -q -y build-essential cmake
+          run: |
+            cmake -S test -B build -DCMAKE_BUILD_TYPE=RelWithDebInfo
+            cmake --build build -j
+            cd build && ./subprocess_test '--filter=*divzero'
+
+  # NetBSD twice on purpose: addchdir arrived in 10.0, so 9.x takes another path.
+  bsd:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { os: freebsd, version: "14.3", pkg: "sudo pkg install -y cmake" }
+          - { os: netbsd,  version: "9.4",  pkg: "sudo pkgin -y install cmake" }
+          - { os: netbsd,  version: "10.1", pkg: "sudo pkgin -y install cmake" }
+          - { os: openbsd, version: "7.9",  pkg: "sudo pkg_add cmake" }
+    name: ${{ matrix.os }} ${{ matrix.version }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cross-platform-actions/action@v1.4.0
+        with:
+          operating_system: ${{ matrix.os }}
+          version: ${{ matrix.version }}
+          run: |
+            ${{ matrix.pkg }}
+            cmake -S test -B build -DCMAKE_BUILD_TYPE=RelWithDebInfo
+            cmake --build build
+            ctest --test-dir build --output-on-failure
+
+  macos-deployment-target:
+    runs-on: macos-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        target: ["10.14", "10.15", "11.0"]
+    name: macOS deployment target ${{ matrix.target }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Build and test
+        run: |
+          cmake -S test -B build \
+            -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+            -DCMAKE_OSX_DEPLOYMENT_TARGET=${{ matrix.target }}
+          cmake --build build -j
+          ctest --test-dir build --output-on-failure

subprocess.h

@@ -276,6 +276,11 @@ subprocess_weak int subprocess_alive(struct subprocess_s *const process);
 #endif
 
 #if defined(__NetBSD__)
+/* <sys/param.h> pulls in <sys/inttypes.h>, which hides the PRI macros from C++
+   before C++11 behind an include guard, so this has to be set before it. */
+#if defined(__cplusplus) && !defined(__STDC_FORMAT_MACROS)
+#define __STDC_FORMAT_MACROS 1
+#endif
 #include <sys/param.h>
 #endif
 

test/CMakeLists.txt

@@ -154,13 +154,17 @@ subprocess_set_cxx_flags(test98.cpp "-std=gnu++98")
 subprocess_set_cxx_flags(test11.cpp "-std=c++11" "-Wno-c++98-compat")
 subprocess_set_cxx_flags(test14.cpp "-std=c++14" "-Wno-c++98-compat")
 subprocess_set_cxx_flags(test17.cpp "-std=c++17" "-Wno-c++98-compat")
-# GCC 8 and clang 9 only accept the pre-release spelling -std=c++2a.
+# GCC 8 and clang 9 only accept the pre-release spelling -std=c++2a, and GCC 7
+# and older accept neither, so the file falls back to the compiler default.
 include(CheckCXXCompilerFlag)
 check_cxx_compiler_flag("-std=c++20" SUBPROCESS_CXX_HAS_STD_CXX20)
+check_cxx_compiler_flag("-std=c++2a" SUBPROCESS_CXX_HAS_STD_CXX2A)
 if(SUBPROCESS_CXX_HAS_STD_CXX20)
   subprocess_set_cxx_flags(test20.cpp "-std=c++20" "-Wno-c++98-compat")
-else()
+elseif(SUBPROCESS_CXX_HAS_STD_CXX2A)
   subprocess_set_cxx_flags(test20.cpp "-std=c++2a" "-Wno-c++98-compat")
+else()
+  subprocess_set_cxx_flags(test20.cpp "" "-Wno-c++98-compat")
 endif()
 subprocess_set_cxx_flags(pre_windows.cpp  "" "-Wno-c++98-compat")
 subprocess_set_cxx_flags(post_windows.cpp "" "-Wno-c++98-compat")