-#define memcached_string_length(A) (size_t)(A->end - A->string)
-#define memcached_string_set_length(A, B) A->end= A->string + B
-#define memcached_string_size(A) A->current_size
-#define memcached_string_value(A) A->string
+#define memcached_string_length(A) (size_t)((A)->end - (A)->string)
+#define memcached_string_set_length(A, B) (A)->end= (A)->string + B
+#define memcached_string_size(A) (A)->current_size
+#define memcached_string_value(A) (A)->string