diff --git a/example/ex11-use-pool.c b/example/ex11-use-pool.c
index 81a93c27..c56a0dff 100644
--- a/example/ex11-use-pool.c
+++ b/example/ex11-use-pool.c
@@ -52,22 +52,22 @@ int f(string_t x, bitset_t b, bstring_t y)
 #include "m-array.h"
 
 ARRAY_DEF(array, int)
-ARRAY_DEF(array_str, string_t, M_STRING_POOL_OPLIST)
+ARRAY_DEF(array_str, string_t)
 
 #include "m-prioqueue.h"
 
 PRIOQUEUE_DEF(prio, int)
-PRIOQUEUE_DEF(prio_str, string_t, M_STRING_POOL_OPLIST)
+PRIOQUEUE_DEF(prio_str, string_t)
 
 #include "m-rbtree.h"
 
 RBTREE_DEF(rbtree, int)
-RBTREE_DEF(rbtree_str, string_t, M_STRING_POOL_OPLIST)
+RBTREE_DEF(rbtree_str, string_t)
 
 #include "m-list.h"
 
 LIST_DEF(list, int)
-LIST_DEF(list_str, string_t, M_STRING_POOL_OPLIST)
+LIST_DEF(list_str, string_t)
 
 #include "m-bptree.h"
 
@@ -76,10 +76,10 @@ BPTREE_DEF2(bptree, 5, int, int)
 #include "m-dict.h"
 
 DICT_DEF2(dict, int, int)
-DICT_DEF2(dict_str, string_t, M_STRING_POOL_OPLIST, string_t, M_STRING_POOL_OPLIST)
+DICT_DEF2(dict_str, string_t, string_t)
 
 DICT_SET_DEF(set, int)
-DICT_SET_DEF(set_str, string_t, M_STRING_POOL_OPLIST)
+DICT_SET_DEF(set_str, string_t)
 
 static inline bool oor_equal_p(int k, char n)
 {
@@ -94,11 +94,11 @@ static inline int  oor_set(char n)
 DICT_OA_DEF2(dict_oa,
     int, M_OPEXTEND(M_BASIC_OPLIST, OOR_EQUAL(oor_equal_p), OOR_SET(API_4(oor_set))),
     int, M_BASIC_OPLIST)
-DICT_OA_DEF2(dict2_str, string_t, M_STRING_POOL_OPLIST, string_t, M_STRING_POOL_OPLIST)
+DICT_OA_DEF2(dict2_str, string_t, string_t)
 
 DICT_OASET_DEF(set_oa,
     int, M_OPEXTEND(M_BASIC_OPLIST, OOR_EQUAL(oor_equal_p), OOR_SET(API_4(oor_set))) )
-DICT_OASET_DEF(set2_str, string_t, M_STRING_POOL_OPLIST)
+DICT_OASET_DEF(set2_str, string_t)
 
 #include "m-buffer.h"
 
@@ -108,16 +108,16 @@ BUFFER_DEF(buffer2, int, 0, M_BUFFER_STACK)
 M_QUEUE_MPMC_DEF(queue1, int, M_BUFFER_STACK)
 M_QUEUE_SPSC_DEF(queue2, int, M_BUFFER_STACK)
 
-BUFFER_DEF(buffer11, string_t, 10, M_BUFFER_QUEUE, M_STRING_POOL_OPLIST)
-BUFFER_DEF(buffer22, string_t, 0, M_BUFFER_STACK, M_STRING_POOL_OPLIST)
+BUFFER_DEF(buffer11, string_t, 10, M_BUFFER_QUEUE)
+BUFFER_DEF(buffer22, string_t, 0, M_BUFFER_STACK)
 
-M_QUEUE_MPMC_DEF(queue11, string_t, M_BUFFER_STACK, M_STRING_POOL_OPLIST)
-M_QUEUE_SPSC_DEF(queue22, string_t, M_BUFFER_STACK, M_STRING_POOL_OPLIST)
+M_QUEUE_MPMC_DEF(queue11, string_t, M_BUFFER_STACK)
+M_QUEUE_SPSC_DEF(queue22, string_t, M_BUFFER_STACK)
 
 #include "m-deque.h"
 
 M_DEQUE_DEF(deque, int)
-M_DEQUE_DEF(deque_str, string_t, M_STRING_POOL_OPLIST)
+M_DEQUE_DEF(deque_str, string_t)
 
 #include "m-snapshot.h"
 
@@ -128,27 +128,27 @@ M_SNAPSHOT_MPMC_DEF(snap3, int)
 #include "m-tree.h"
 
 M_TREE_DEF(tree, int)
-M_TREE_DEF(tree_str, string_t, M_STRING_POOL_OPLIST)
+M_TREE_DEF(tree_str, string_t)
 
 #include "m-tuple.h"
 
 M_TUPLE_DEF2(tuple1, (num, int) )
-M_TUPLE_DEF2(tuple2, (num, int), (name, string_t, M_STRING_POOL_OPLIST) )
+M_TUPLE_DEF2(tuple2, (num, int), (name, string_t) )
 
 #include "m-variant.h"
 
 M_VARIANT_DEF2(variant1, (num, int) )
-M_VARIANT_DEF2(variant2, (num, int), (name, string_t, M_STRING_POOL_OPLIST) )
+M_VARIANT_DEF2(variant2, (num, int), (name, string_t) )
 
 #include "m-worker.h"
 
 M_WORKER_SPAWN_DEF2(worker_int, (in, int) )
-M_WORKER_SPAWN_DEF2(worker_str, (str, string_t, M_STRING_POOL_OPLIST) )
+M_WORKER_SPAWN_DEF2(worker_str, (str, string_t) )
 
 #include "m-shared-ptr.h"
 
 M_SHARED_PTR_DEF(shared_int, int)
-M_SHARED_PTR_DEF(shared_str, string_t, M_STRING_POOL_OPLIST)
+M_SHARED_PTR_DEF(shared_str, string_t)
 
 int main(void)
 {
diff --git a/m-string.h b/m-string.h
index 10e24a15..fefef8b7 100644
--- a/m-string.h
+++ b/m-string.h
@@ -2142,6 +2142,7 @@ namespace m_lib {
 #endif
 
 /* Define the OPLIST of a STRING */
+#ifndef M_USE_POOL
 #define M_STRING_OPLIST                                                       \
   (INIT(m_string_init),INIT_SET(m_string_init_set), SET(m_string_set),        \
    INIT_WITH(M_STR1NG_INIT_WITH),                                             \
@@ -2166,8 +2167,8 @@ namespace m_lib {
    ,IT_CREF(m_string_cref), PUSH(m_string_push_u)                             \
    ,EMPLACE_TYPE(const char*)                                                 \
    )
-
-#define M_STRING_POOL_OPLIST                                                  \
+#else
+#define M_STRING_OPLIST                                                       \
    (INIT(m_string_init),INIT_SET(API_0P(m_string_init_set)), SET(API_0P(m_string_set)), \
     INIT_WITH(M_STR1NG_INIT_WITH),                                            \
     INIT_MOVE(m_string_init_move), MOVE(API_0P(m_string_move)),               \
@@ -2191,13 +2192,10 @@ namespace m_lib {
     ,IT_CREF(m_string_cref), PUSH(API_0P(m_string_push_u))                    \
     ,EMPLACE_TYPE(const char*)                                                \
     )
+#endif
 
 /* Register the OPLIST as a global one */
-#ifdef M_USE_POOL
-#define M_OPL_m_string_t() M_STRING_POOL_OPLIST
-#else
 #define M_OPL_m_string_t() M_STRING_OPLIST
-#endif
 
 /* Register the string_t oplist as a generic type */
 #define M_GENERIC_ORG_MLIB_COMP_CORE_OPLIST_1() M_STRING_OPLIST