+#define array_len(array) (array).len
+#define array_size(array) (array).size
+#define array_elt_len(array) sizeof(*(array).data)
+#define array_byte_len(array) ((array).len * array_elt_len(array))
+
+#define array_lock(array) \
+ ((array).locked \
+ || (mlock((array).data, array_byte_len(array)) == 0 \
+ && ((array).locked = true)))
+#define array_unlock(array) \
+ if ((array).locked) { \
+ (void)munlock((array).data, array_byte_len(array)); \
+ (array).locked = false; \
+ }
+