diff --git a/mdbx.h b/mdbx.h
index 96e6e63e..160bef64 100644
--- a/mdbx.h
+++ b/mdbx.h
@@ -1633,7 +1633,7 @@ LIBMDBX_API int mdbx_dbi_sequence(MDBX_txn *txn, MDBX_dbi dbi, uint64_t *result,
 
 /*----------------------------------------------------------------------------*/
 /* attribute support functions for Nexenta */
-typedef uint64_t mdbx_attr_t;
+typedef uint_fast64_t mdbx_attr_t;
 
 /* Store by cursor with attribute.
  *
@@ -1668,8 +1668,9 @@ typedef uint64_t mdbx_attr_t;
  *  - MDBX_TXN_FULL  - the transaction has too many dirty pages.
  *  - MDBX_EACCES    - an attempt was made to write in a read-only transaction.
  *  - MDBX_EINVAL    - an invalid parameter was specified. */
-int mdbx_cursor_put_attr(MDBX_cursor *cursor, MDBX_val *key, MDBX_val *data,
-                         mdbx_attr_t attr, unsigned flags);
+LIBMDBX_API int mdbx_cursor_put_attr(MDBX_cursor *cursor, MDBX_val *key,
+                                     MDBX_val *data, mdbx_attr_t attr,
+                                     unsigned flags);
 
 /* Store items and attributes into a database.
  *
@@ -1713,8 +1714,8 @@ int mdbx_cursor_put_attr(MDBX_cursor *cursor, MDBX_val *key, MDBX_val *data,
  *  - MDBX_TXN_FULL  - the transaction has too many dirty pages.
  *  - MDBX_EACCES    - an attempt was made to write in a read-only transaction.
  *  - MDBX_EINVAL    - an invalid parameter was specified. */
-int mdbx_put_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
-                  mdbx_attr_t attr, unsigned flags);
+LIBMDBX_API int mdbx_put_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key,
+                              MDBX_val *data, mdbx_attr_t attr, unsigned flags);
 
 /* Set items attribute from a database.
  *
@@ -1733,8 +1734,8 @@ int mdbx_put_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
  * possible errors are:
  *	 - MDBX_NOTFOUND   - the key-value pair was not in the database.
  *	 - MDBX_EINVAL     - an invalid parameter was specified. */
-int mdbx_set_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
-                  mdbx_attr_t attr);
+LIBMDBX_API int mdbx_set_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key,
+                              MDBX_val *data, mdbx_attr_t attr);
 
 /* Get items attribute from a database cursor.
  *
@@ -1753,8 +1754,9 @@ int mdbx_set_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
  * possible errors are:
  *  - MDBX_NOTFOUND  - no matching key found.
  *  - MDBX_EINVAL    - an invalid parameter was specified. */
-int mdbx_cursor_get_attr(MDBX_cursor *mc, MDBX_val *key, MDBX_val *data,
-                         mdbx_attr_t *attrptr, MDBX_cursor_op op);
+LIBMDBX_API int mdbx_cursor_get_attr(MDBX_cursor *mc, MDBX_val *key,
+                                     MDBX_val *data, mdbx_attr_t *attrptr,
+                                     MDBX_cursor_op op);
 
 /* Get items attribute from a database.
  *
@@ -1782,8 +1784,8 @@ int mdbx_cursor_get_attr(MDBX_cursor *mc, MDBX_val *key, MDBX_val *data,
  * possible errors are:
  *  - MDBX_NOTFOUND  - the key was not in the database.
  *  - MDBX_EINVAL   - an invalid parameter was specified. */
-int mdbx_get_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
-                  mdbx_attr_t *attrptr);
+LIBMDBX_API int mdbx_get_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key,
+                              MDBX_val *data, mdbx_attr_t *attrptr);
 
 #ifdef __cplusplus
 }
diff --git a/src/mdbx.c b/src/mdbx.c
index df7bec11..63c4b958 100644
--- a/src/mdbx.c
+++ b/src/mdbx.c
@@ -11151,9 +11151,9 @@ int mdbx_get_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
 
 int mdbx_put_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
                   mdbx_attr_t attr, unsigned flags) {
-  MDBX_val reserve = {.iov_base = NULL,
-                      .iov_len =
-                          (data ? data->iov_len : 0) + sizeof(mdbx_attr_t)};
+  MDBX_val reserve;
+  reserve.iov_base = NULL;
+  reserve.iov_len = (data ? data->iov_len : 0) + sizeof(mdbx_attr_t);
 
   int rc = mdbx_put(txn, dbi, key, &reserve, flags | MDBX_RESERVE);
   if (unlikely(rc != MDBX_SUCCESS))
@@ -11164,9 +11164,9 @@ int mdbx_put_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
 
 int mdbx_cursor_put_attr(MDBX_cursor *cursor, MDBX_val *key, MDBX_val *data,
                          mdbx_attr_t attr, unsigned flags) {
-  MDBX_val reserve = {.iov_base = NULL,
-                      .iov_len =
-                          (data ? data->iov_len : 0) + sizeof(mdbx_attr_t)};
+  MDBX_val reserve;
+  reserve.iov_base = NULL;
+  reserve.iov_len = (data ? data->iov_len : 0) + sizeof(mdbx_attr_t);
 
   int rc = mdbx_cursor_put(cursor, key, &reserve, flags | MDBX_RESERVE);
   if (unlikely(rc != MDBX_SUCCESS))
@@ -11177,12 +11177,6 @@ int mdbx_cursor_put_attr(MDBX_cursor *cursor, MDBX_val *key, MDBX_val *data,
 
 int mdbx_set_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
                   mdbx_attr_t attr) {
-  MDBX_cursor mc;
-  MDBX_xcursor mx;
-  MDBX_val old_data;
-  mdbx_attr_t old_attr;
-  int rc;
-
   if (unlikely(!key || !txn))
     return EINVAL;
 
@@ -11195,8 +11189,11 @@ int mdbx_set_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
   if (unlikely(txn->mt_flags & (MDBX_TXN_RDONLY | MDBX_TXN_BLOCKED)))
     return (txn->mt_flags & MDBX_TXN_RDONLY) ? EACCES : MDBX_BAD_TXN;
 
+  MDBX_cursor mc;
+  MDBX_xcursor mx;
+  MDBX_val old_data;
   mdbx_cursor_init(&mc, txn, dbi, &mx);
-  rc = mdbx_cursor_set(&mc, key, &old_data, MDBX_SET, NULL);
+  int rc = mdbx_cursor_set(&mc, key, &old_data, MDBX_SET, NULL);
   if (unlikely(rc != MDBX_SUCCESS)) {
     if (rc == MDBX_NOTFOUND && data) {
       mc.mc_next = txn->mt_cursors[dbi];
@@ -11207,6 +11204,7 @@ int mdbx_set_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
     return rc;
   }
 
+  mdbx_attr_t old_attr;
   rc = mdbx_attr_peek(&old_data, &old_attr);
   if (unlikely(rc != MDBX_SUCCESS))
     return rc;