Implement fallback for systems without qsort_r

.github/workflows/freebsd.yml

@@ -0,0 +1,78 @@
+name: FreeBSD CI
+
+# Triggers the workflow on push or pull request or on demand
+on:
+  workflow_dispatch:
+  push:
+  pull_request:
+    branches: [ develop ]
+    paths-ignore:
+      - '.github/CODEOWNERS'
+      - '.github/FUNDING.yml'
+      - 'doc/**'
+      - 'release_docs/**'
+      - 'ACKNOWLEDGEMENTS'
+      - 'LICENSE**'
+      - '**.md'
+
+# Using concurrency to cancel any in-progress job or run
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref && github.ref || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  freebsd-build-and-test:
+    runs-on: ubuntu-latest
+    name: FreeBSD 14.2 Build and Test
+
+    # Don't run the action if the commit message says to skip CI
+    if: "!contains(github.event.head_commit.message, 'skip-ci')"
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v5
+
+      - name: Build and test on FreeBSD
+        uses: vmactions/freebsd-vm@v1
+        with:
+          release: '14.2'
+          usesh: true
+          prepare: |
+            pkg install -y cmake ninja pkgconf bash curl
+          run: |
+            set -e
+
+            # Configure the build
+            mkdir build
+            cd build
+            cmake -C ../config/cmake/cacheinit.cmake \
+              -G Ninja \
+              --log-level=VERBOSE \
+              -DCMAKE_BUILD_TYPE=Release \
+              -DBUILD_SHARED_LIBS:BOOL=ON \
+              -DHDF5_ENABLE_ALL_WARNINGS:BOOL=ON \
+              -DHDF5_ENABLE_PARALLEL:BOOL=OFF \
+              -DHDF5_BUILD_CPP_LIB:BOOL=ON \
+              -DHDF5_BUILD_FORTRAN:BOOL=OFF \
+              -DHDF5_BUILD_JAVA:BOOL=OFF \
+              -DHDF5_BUILD_DOC:BOOL=OFF \
+              -DHDF5_ENABLE_ZLIB_SUPPORT:BOOL=ON \
+              -DHDF5_ENABLE_SZIP_SUPPORT:BOOL=ON \
+              -DLIBAEC_USE_LOCALCONTENT:BOOL=OFF \
+              -DZLIB_USE_LOCALCONTENT:BOOL=OFF \
+              -DHDF5_TEST_API:BOOL=ON \
+              -DHDF5_TEST_SHELL_SCRIPTS:BOOL=OFF \
+              -DENABLE_EXTENDED_TESTS:BOOL=OFF \
+              ..
+            echo ""
+
+            # Build
+            cmake --build . --parallel 3 --config Release
+            echo ""
+
+            # Run tests
+            ctest . --parallel 2 -C Release -V
+            echo ""

config/ConfigureChecks.cmake

@@ -443,6 +443,15 @@ CHECK_FUNCTION_EXISTS (asprintf          ${HDF_PREFIX}_HAVE_ASPRINTF)
 CHECK_FUNCTION_EXISTS (vasprintf         ${HDF_PREFIX}_HAVE_VASPRINTF)
 CHECK_FUNCTION_EXISTS (waitpid           ${HDF_PREFIX}_HAVE_WAITPID)
 
+# Check for reentrant qsort variants (qsort_r on Unix/BSD, qsort_s on Windows)
+# Note: qsort_r has different signatures on GNU/Linux vs BSD/macOS, but we just
+# check for existence here. Signature differences will be handled in the code.
+CHECK_FUNCTION_EXISTS (qsort_r _HAVE_QSORT_R_TMP)
+CHECK_FUNCTION_EXISTS (qsort_s _HAVE_QSORT_S_TMP)
+if (_HAVE_QSORT_R_TMP OR _HAVE_QSORT_S_TMP)
+  set (${HDF_PREFIX}_HAVE_QSORT_REENTRANT 1)
+endif ()
+
 #-----------------------------------------------------------------------------
 # sigsetjmp is special; may actually be a macro
 #-----------------------------------------------------------------------------

src/H5private.h

@@ -654,6 +654,11 @@ H5_DLL void HDqsort_context(void *base, size_t nel, size_t size,
                             int (*compar)(const void *, const void *, void *), void *arg);
 #endif
 
+#ifndef H5_HAVE_QSORT_REENTRANT
+H5_DLL void HDqsort_fallback(void *base, size_t nel, size_t size,
+                             int (*compar)(const void *, const void *, void *), void *arg);
+#endif
+
 #ifndef HDfseek
 #define HDfseek(F, O, W) fseeko(F, O, W)
 #endif
@@ -770,11 +775,16 @@ H5_DLL void HDqsort_context(void *base, size_t nel, size_t size,
 #define HDunsetenv(S) unsetenv(S)
 #endif
 #ifndef HDqsort_r
+#ifdef H5_HAVE_QSORT_REENTRANT
 #ifdef H5_HAVE_DARWIN
 #define HDqsort_r(B, N, S, C, A) HDqsort_context(B, N, S, C, A)
 #else
 #define HDqsort_r(B, N, S, C, A) qsort_r(B, N, S, C, A)
 #endif
+#else
+/* No native qsort_r/qsort_s available - use fallback implementation */
+#define HDqsort_r(B, N, S, C, A) HDqsort_fallback(B, N, S, C, A)
+#endif
 #endif
 #ifndef HDvasprintf
 #ifdef H5_HAVE_VASPRINTF

src/H5pubconf.h.in

@@ -258,6 +258,9 @@
 /* Define to 1 if you have the <pwd.h> header file. */
 #cmakedefine H5_HAVE_PWD_H @H5_HAVE_PWD_H@
 
+/* Define to 1 if you have a reentrant qsort function (qsort_r or qsort_s). */
+#cmakedefine H5_HAVE_QSORT_REENTRANT @H5_HAVE_QSORT_REENTRANT@
+
 /* Define whether the Read-Only S3 virtual file driver (VFD) should be
    compiled */
 #cmakedefine H5_HAVE_ROS3_VFD @H5_HAVE_ROS3_VFD@

src/H5system.c

@@ -1456,3 +1456,99 @@ HDqsort_context(void *base, size_t nel, size_t size, int (*compar)(const void *,
 #endif
 }
 #endif
+
+/*
+ * HDqsort_fallback - Fallback qsort implementation for platforms without qsort_r/qsort_s
+ *
+ * For platforms that don't provide any reentrant qsort variant, this fallback uses
+ * thread-local storage (when thread-safety is
+ * enabled) or a global variable to store the comparator context, then uses standard qsort().
+ *
+ * The threadsafe version uses thread-local storage but does not support recursive sorting (a
+ * comparator calling HDqsort_r) as it would overwrite the previous context.
+ */
+#ifndef H5_HAVE_QSORT_REENTRANT
+
+typedef struct HDqsort_fallback_context_t {
+    int (*gnu_compar)(const void *, const void *, void *);
+    void *gnu_arg;
+} HDqsort_fallback_context_t;
+
+#ifdef H5_HAVE_THREADSAFE
+/* Thread-local storage approach for thread-safe builds */
+static H5TS_key_t  HDqsort_fallback_key;
+static H5TS_once_t HDqsort_fallback_key_once = H5TS_ONCE_INITIALIZER;
+
+static void
+HDqsort_fallback_key_init(void)
+{
+    /* Create the thread-local storage key (no destructor needed) */
+    H5TS_key_create(&HDqsort_fallback_key, NULL);
+}
+
+static int
+HDqsort_fallback_wrapper(const void *a, const void *b)
+{
+    HDqsort_fallback_context_t *ctx = NULL;
+
+    /* Retrieve the context from thread-local storage
+     * This should never fail since we just set it in HDqsort_fallback() */
+    if (H5_UNLIKELY(H5TS_key_get_value(HDqsort_fallback_key, (void **)&ctx) < 0))
+        return 0; /* Should never happen, but return 0 (equal) if it does */
+
+    /* Call the original GNU-style comparator with context */
+    return ctx->gnu_compar(a, b, ctx->gnu_arg);
+}
+
+void
+HDqsort_fallback(void *base, size_t nel, size_t size, int (*compar)(const void *, const void *, void *),
+                 void *arg)
+{
+    HDqsort_fallback_context_t ctx;
+
+    /* Ensure the TLS key is initialized */
+    H5TS_once(&HDqsort_fallback_key_once, HDqsort_fallback_key_init);
+
+    ctx.gnu_compar = compar;
+    ctx.gnu_arg    = arg;
+
+    /* Store context in thread-local storage */
+    H5TS_key_set_value(HDqsort_fallback_key, &ctx);
+
+    qsort(base, nel, size, HDqsort_fallback_wrapper);
+
+    /* Clear the thread-local storage */
+    H5TS_key_set_value(HDqsort_fallback_key, NULL);
+}
+
+#else
+/* Non-threadsafe: use global variable */
+static HDqsort_fallback_context_t *HDqsort_fallback_global_ctx = NULL;
+
+static int
+HDqsort_fallback_wrapper(const void *a, const void *b)
+{
+    /* Call the original GNU-style comparator with context from global */
+    return HDqsort_fallback_global_ctx->gnu_compar(a, b, HDqsort_fallback_global_ctx->gnu_arg);
+}
+
+void
+HDqsort_fallback(void *base, size_t nel, size_t size, int (*compar)(const void *, const void *, void *),
+                 void *arg)
+{
+    HDqsort_fallback_context_t ctx;
+
+    ctx.gnu_compar = compar;
+    ctx.gnu_arg    = arg;
+
+    /* Store context in global variable */
+    HDqsort_fallback_global_ctx = &ctx;
+
+    qsort(base, nel, size, HDqsort_fallback_wrapper);
+
+    /* Clear the global pointer */
+    HDqsort_fallback_global_ctx = NULL;
+}
+#endif /* H5_HAVE_THREADSAFE */
+
+#endif /* !H5_HAVE_QSORT_REENTRANT */