Prefer HAVE_ALIGNED_ALLOC when available in zng_alloc

Added some more helpful comments for people who come across this code.

diff --git a/zutil_p.h b/zutil_p.h
index caec91d50d364c887d5b430d156ff0084377cc11..bc6f9698d261ae7d65a8a51d181f4d94a3f03f32 100644 (file)
--- a/zutil_p.h
+++ b/zutil_p.h
@@ -16,15 +16,17 @@
 
 /* Function to allocate 16 or 64-byte aligned memory */
 static inline void *zng_alloc(size_t size) {
-#ifdef HAVE_POSIX_MEMALIGN
+#ifdef HAVE_ALIGNED_ALLOC
+    return (void *)aligned_alloc(64, size);  /* Defined in C11 */
+#elif defined(HAVE_POSIX_MEMALIGN)
     void *ptr;
     return posix_memalign(&ptr, 64, size) ? NULL : ptr;
 #elif defined(_WIN32)
     return (void *)_aligned_malloc(size, 64);
 #elif defined(__APPLE__)
-    return (void *)malloc(size);     /* MacOS always aligns to 16 bytes */
-#elif defined(HAVE_ALIGNED_ALLOC)
-    return (void *)aligned_alloc(64, size);
+    /* Fallback for when posix_memalign and aligned_alloc are not available.
+     * On macOS, it always aligns to 16 bytes. */
+    return (void *)malloc(size);
 #else
     return (void *)memalign(64, size);
 #endif