Fix interface of Intrusive List

(Reported by Brian Sipos):
* incorrect clear operator usage
* useless prototype of _insert, inconsistent with the policy of other functions
* syntax error in _insert

README.md

@@ -4777,6 +4777,10 @@ It shall be put within the structure of the object to link, at the top
 level of the structure.
 See example of `ILIST_DEF`.
 
+#### `ILIST_INIT_FIELD(name, object)`
+
+Initialize the fields added by `ILIST_INTERFACE` of the object.
+
 #### `ILIST_DEF(name, type[, oplist])`
 #### `ILIST_DEF_AS(name, name_t, name_it_t, type[, oplist])`
 
@@ -4931,10 +4935,9 @@ or NULL if there is no more object.
 Return the object that is before the object `*obj` in the list
 or NULL if there is no more object.
 
-##### `void name_insert(name_t list, name_it_t it, type x)`
+##### `void name_insert(name_t list, name_it_t it, type *x)`
 
-This method is the same as the generic one,
+This method is the same as the generic one, except it is really `x` that is added in the list, not a copy.
-except it is only created if the `NEW` and `INIT_SET` methods are provided.
 
 ##### `void name_splice_back(name_t list1, name_t list2, name_it_t it)`
 

example/ex-i-list.c

@@ -0,0 +1,56 @@
+#include "m-i-list.h"
+
+typedef struct data_s {
+    M_ILIST_INTERFACE(list1, struct data_s);
+    char *ptr;
+    int  n;
+} data_t;
+
+static void
+data_init(data_t *p)
+{
+    M_ILIST_INIT_FIELD(list1, *p);
+    p->ptr = malloc(100);
+    p->n = 100;
+}
+
+static void
+data_clear(data_t *p)
+{
+    free(p->ptr);
+    p->n = 0;
+}
+
+static void
+data_init_set(data_t *p, data_t s)
+{
+    p->ptr = malloc(s.n);
+    p->n = s.n;
+    memcpy(p->ptr, s.ptr, s.n);
+}
+
+#define DATA_OP (INIT(API_2(data_init)), INIT_SET(API_2(data_init_set)), CLEAR(API_2(data_clear)) )
+
+M_ILIST_DEF(list1, data_t, DATA_OP)
+
+data_t pool[100];
+
+int main(void)
+{
+    list1_t l;
+
+    list1_init(l);
+    data_init(&pool[0]);
+    list1_push_back(l, &pool[0]);
+    data_init(&pool[1]);
+    list1_push_back(l, &pool[1]);
+
+    list1_it_t it;
+    list1_it(it, l);
+    data_init(&pool[2]);
+    list1_insert(l, it, &pool[2]);
+
+    list1_clear(l);
+
+    exit(0);
+}

m-i-list.h

@@ -71,6 +71,10 @@
                 ((__VA_ARGS__, M_BASIC_OPLIST),                               \
                  (__VA_ARGS__ )))
 
+#define M_ILIST_INIT_FIELD(name, obj) do {                                    \
+    (obj).name.next = NULL;                                                   \
+    (obj).name.prev = NULL;                                                   \
+  } while(0)
 
 /*****************************************************************************/
 /******************************** INTERNAL ***********************************/
@@ -117,7 +121,6 @@ typedef struct m_il1st_head_s {
    IT_REF(M_F(name,_ref)),                                                    \
    IT_CREF(M_F(name,_cref)),                                                  \
    IT_REMOVE(M_F(name,_remove)),                                              \
-   M_IF_METHOD(NEW, oplist)(IT_INSERT(M_F(name,_insert)),),                   \
    OPLIST(oplist),                                                            \
    SPLICE_BACK(M_F(name,_splice_back))                                        \
    )
@@ -517,30 +520,22 @@ typedef struct m_il1st_head_s {
     type *obj = M_TYPE_FROM_FIELD(type, it->current,                          \
                                   struct m_il1st_head_s, name);               \
     M_F(name, _unlink)(obj);                                                  \
-    M_CALL_CLEAR(oplist, obj);                                                \
+    M_CALL_CLEAR(oplist, *obj);                                               \
     M_IF_METHOD(DEL, oplist)(M_CALL_DEL(oplist, obj), (void) 0);              \
     M_F(name, _next)(it);                                                     \
   }                                                                           \
                                                                               \
-  M_IF_METHOD2(NEW, INIT_SET, oplist)(                                        \
   M_INLINE void                                                               \
-  M_F(name, _insert)(list_t list, it_t it, type x)                            \
+  M_F(name, _insert)(list_t list, it_t it, type *p)                           \
   {                                                                           \
     M_IL1ST_CONTRACT(name, list);                                             \
     M_IL1ST_NODE_CONTRACT(it->current);                                       \
-    type *p = M_CALL_NEW(oplist, type);                                       \
-    if (M_UNLIKELY_NOMEM (p == NULL)) {                                       \
-      M_MEMORY_FULL (sizeof (type));                                          \
-      return ;                                                                \
-    }                                                                         \
-    M_CALL_INIT_SET(oplist, *p, x);                                           \
     type *obj = M_F(name, _ref)(it);                                          \
     M_F(name, _push_after)(obj, p);                                           \
-    it->current = p;                                                          \
+    it->current = &p->name;                                                   \
     (void) list;                                                              \
     M_IL1ST_CONTRACT(name, list);                                             \
   }                                                                           \
-  , /* NEW & INIT_SET not defined */)                                         \
                                                                               \
   M_INLINE type *                                                             \
   M_F(name, _pop_back)(list_t list)                                           \