+/**
+ * \def rerzalloc(ctx, ptr, type, count)
+ * Resize a ralloc-managed array, preserving data and initializing any newly
+ * allocated data to zero.
+ *
+ * Similar to \c realloc. Unlike C89, passing 0 for \p size does not free the
+ * memory. Instead, it resizes it to a 0-byte ralloc context, just like
+ * calling ralloc_size(ctx, 0). This is different from talloc.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \c sizeof(type) and \p count. This is necessary for security.
+ *
+ * \param ctx The context to use for new allocation. If \p ptr != NULL,
+ * it must be the same as ralloc_parent(\p ptr).
+ * \param ptr Pointer to the array to be resized. May be NULL.
+ * \param type The element type.
+ * \param old_count The number of elements in the previous allocation.
+ * \param new_count The number of elements to allocate.
+ */
+#define rerzalloc(ctx, ptr, type, old_count, new_count) \
+ ((type *) rerzalloc_array_size(ctx, ptr, sizeof(type), old_count, new_count))
+