From ae7e928f88370124406da09ec9a2a410d3754656 Mon Sep 17 00:00:00 2001
From: Joseph Hunkeler <jhunkeler@gmail.com>
Date: Fri, 1 Aug 2025 17:28:04 -0400
Subject: Initial commit

---
 .github/workflows/cmake-multi-platform.yml | 39 ++++++++++++++++++++++++++++++
 main.c                                     | 19 +++++++++++++++
 2 files changed, 58 insertions(+)
 create mode 100644 .github/workflows/cmake-multi-platform.yml
 create mode 100644 main.c

diff --git a/.github/workflows/cmake-multi-platform.yml b/.github/workflows/cmake-multi-platform.yml
new file mode 100644
index 0000000..b4137b5
--- /dev/null
+++ b/.github/workflows/cmake-multi-platform.yml
@@ -0,0 +1,39 @@
+name: CMake on multiple platforms
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      fail-fast: false
+
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+        build_type: [RelWithDebInfo]
+        c_compiler: [gcc, clang]
+        include:
+          - os: macos-latest
+            c_compiler: clang
+          - os: ubuntu-latest
+            c_compiler: gcc
+          - os: ubuntu-latest
+            c_compiler: clang
+        exclude:
+          - os: macos-latest
+            c_compiler: gcc
+
+    steps:
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683  # v4.2.2
+
+    - name: Build
+      run: |
+        ${{ matrix.c_compiler }} -v -Wall -Wextra -o see_defs main.c
+
+    - name: Test
+      run: ./see_defs
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..95ff687
--- /dev/null
+++ b/main.c
@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <sys/cdefs.h>
+
+int main(int argc, char *argv[]) {
+#ifdef _XOPEN_SOURCE
+    printf("_XOPEN_SOURCE = %luL\n", _XOPEN_SOURCE);
+#endif
+
+#ifdef _POSIX_C_SOURCE
+    printf("_POSIX_C_SOURCE = %luL\n", _POSIX_C_SOURCE);
+#endif
+
+#ifdef __DARWIN_C_LEVEL
+    printf("__DARWIN_C_LEVEL = %luL\n", __DARWIN_C_LEVEL);
+#endif
+
+    return 0;
+}
+
-- 
cgit