diff --git a/mdbx.h b/mdbx.h
index ae9e5ca5..1ecfcef3 100644
--- a/mdbx.h
+++ b/mdbx.h
@@ -1728,7 +1728,7 @@ LIBMDBX_API int mdbx_env_pgwalk(MDB_txn *txn, MDBX_pgvisitor_func *visitor,
 typedef struct mdbx_canary { uint64_t x, y, z, v; } mdbx_canary;
 
 LIBMDBX_API int mdbx_canary_put(MDB_txn *txn, const mdbx_canary *canary);
-LIBMDBX_API size_t mdbx_canary_get(MDB_txn *txn, mdbx_canary *canary);
+LIBMDBX_API int mdbx_canary_get(MDB_txn *txn, mdbx_canary *canary);
 
 /* Returns:
  *	- MDBX_RESULT_TRUE	when no more data available
diff --git a/src/mdbx.c b/src/mdbx.c
index 003ef5ed..3ed4c46d 100644
--- a/src/mdbx.c
+++ b/src/mdbx.c
@@ -9792,14 +9792,14 @@ int mdbx_canary_put(MDB_txn *txn, const mdbx_canary *canary) {
   return MDB_SUCCESS;
 }
 
-size_t mdbx_canary_get(MDB_txn *txn, mdbx_canary *canary) {
-  if (unlikely(!txn || txn->mt_signature != MDBX_MT_SIGNATURE))
-    return 0;
+int mdbx_canary_get(MDB_txn *txn, mdbx_canary *canary) {
+  if (unlikely(txn == NULL || canary == NULL))
+    return EINVAL;
+  if (unlikely(txn->mt_signature != MDBX_MT_SIGNATURE))
+    return MDBX_EBADSIGN;
 
-  if (likely(canary))
-    *canary = txn->mt_canary;
-
-  return txn->mt_txnid;
+  *canary = txn->mt_canary;
+  return MDB_SUCCESS;
 }
 
 int mdbx_cursor_on_first(MDB_cursor *mc) {