diff --git a/src/main/java/org/lmdbjava/Env.java b/src/main/java/org/lmdbjava/Env.java
@@ -41,6 +41,7 @@
import java.util.List;

import jnr.ffi.Pointer;
import jnr.ffi.byref.PointerByReference;
import org.lmdbjava.Library.MDB_envinfo;
import org.lmdbjava.Library.MDB_stat;
@@ -500,6 +501,15 @@ private void validatePath(final File path) {
    validateDirectoryEmpty(path);
  }

  /**
   * Object has already been closed and the operation is therefore prohibited.
   */
@@ -530,6 +540,7 @@ public AlreadyOpenException() {
    }
  }

  /**
   * Builder for configuring and opening Env.
   *
@@ -595,6 +606,7 @@ public Env<T> open(final File path, final EnvFlags... flags) {
      return open(path, 0664, flags);
    }

    /**
     * Sets the map size.
     *

diff --git a/src/main/java/org/lmdbjava/Library.java b/src/main/java/org/lmdbjava/Library.java
@@ -291,7 +291,7 @@ int mdb_put(@In Pointer txn, @In Pointer dbi, @In Pointer key,
                @In Pointer data,
                int flags);

-    int mdb_reader_check(@In Pointer env, int dead);

    int mdb_set_compare(@In Pointer txn, @In Pointer dbi, ComparatorCallback cb);