Add esqlite3:changes/3 function to get nr of affected rows

src/esqlite3.erl

@@ -23,8 +23,9 @@
 %% higher-level export
 -export([open/1, open/2, 
          exec/2, exec/3,
+         changes/1, changes/2,
          insert/2,
-         prepare/2, prepare/3, 
+         prepare/2, prepare/3,
          step/1, step/2, 
          bind/2, bind/3, 
          fetchone/1,
@@ -200,6 +201,16 @@ exec(Sql, {connection, _Ref, Connection}, Timeout) ->
     ok = esqlite3_nif:exec(Connection, Ref, self(), Sql),
     receive_answer(Ref, Timeout).
 
+%% @doc Return the number of affected rows of last statement.
+changes(Connection) ->
+    changes(Connection, ?DEFAULT_TIMEOUT).
+
+%% @doc Return the number of affected rows of last statement.
+changes({connection, _Ref, Connection}, Timeout) ->
+    Ref = make_ref(),
+    ok = esqlite3_nif:changes(Connection, Ref, self()),
+    receive_answer(Ref, Timeout).
+
 %% @doc Insert records, returns the last rowid.
 %%
 %% @spec insert(iolist(), connection()) -> {ok, integer()} |  {error, error_message()}

src/esqlite3_nif.erl

@@ -24,6 +24,7 @@
 -export([start/0,
     open/4,
     exec/4,
+    changes/3,
     insert/4,
     prepare/4,
     step/3,
@@ -70,6 +71,14 @@ open(_Db, _Ref, _Dest, _Filename) ->
 exec(_Db, _Ref, _Dest, _Sql) ->
     exit(nif_library_not_loaded).
 
+%% @doc Get the number of affected rows of last statement
+%% 
+%% When the statement is executed Dest will receive message {Ref, answer()}
+%% with answer() integer | {error, reason()}
+%%
+changes(_Db, _Ref, _Dest) ->
+    exit(nif_library_not_loaded).
+
 %% @doc
 %%
 %% @spec prepare(connection(), reference(), pid(), string()) -> ok | {error, message()}