Merge branch 'zandra/stdlib/optional-callbacks/OTP-13801'

* zandra/stdlib/optional-callbacks/OTP-13801:
  wx: make wx_object callbacks optional
  stdlib: Make gen_fsm callbacks optional
  stdlib: Make gen_event callbacks optional
  stdlib: Make gen_server callbacks optional

1 files changed, 40 insertions, 0 deletions

diff --git a/lib/stdlib/test/gen_event_SUITE_data/oc_event.erl b/lib/stdlib/test/gen_event_SUITE_data/oc_event.erl
new file mode 100644
index 0000000000..eb664ef550
--- /dev/null
+++ b/lib/stdlib/test/gen_event_SUITE_data/oc_event.erl
@@ -0,0 +1,40 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2017. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+-module(oc_event).
+
+-behaviour(gen_event).
+
+%% API
+-export([start/0]).
+
+%% gen_event callbacks
+-export([init/1]).
+
+-define(SERVER, ?MODULE).
+
+-record(state, {}).
+
+start() ->
+    {ok, Pid} = gen_event:start({local, ?SERVER}),
+    gen_event:add_handler(?SERVER, ?MODULE, []),
+    {ok, Pid}.
+
+init([]) ->
+    {ok, #state{}}.