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Add a way to remove a single event listener (#20983) (#25535)
Fixes: #20983
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‎ChangeLog.md‎

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@@ -20,6 +20,8 @@ See docs/process.md for more on how version tagging works.
2020

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4.0.20 (in development)
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-----------------------
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- Added `emscripten_html5_remove_event_listener` function in `html5.h` in order to be
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able to remove a single callback. (#25535)
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- The standalone `file_packager.py` script no longer supports `--embed` with JS
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output (use `--obj-output` is now required for embedding data). This usage
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has been producing a warning since #16050 which is now an error. (#25049)

‎site/source/docs/api_reference/html5.h.rst‎

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@@ -90,6 +90,54 @@ The ``useCapture`` parameter maps to ``useCapture`` in `EventTarget.addEventLis
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Most functions return the result using the type :c:data:`EMSCRIPTEN_RESULT`. Zero and positive values denote success. Negative values signal failure. None of the functions fail or abort by throwing a JavaScript or C++ exception. If a particular browser does not support the given feature, the value :c:data:`EMSCRIPTEN_RESULT_NOT_SUPPORTED` will be returned at the time the callback is registered.
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Unregister function
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-------------------
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In order to unregister a single event handler callback, call the following function:
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.. code-block:: cpp
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EMSCRIPTEN_RESULT emscripten_html5_remove_event_listener(
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const char *target, // ID of the target HTML element.
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void *userData, // User-defined data (passed to the callback).
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int eventTypeId, // The event type ID (EMSCRIPTEN_EVENT_XXX).
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void *callback // Callback function.
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);
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The ``target``, ``userData`` and ``callback`` parameters are the same parameters provided in ``emscripten_set_some_callback`` with the only difference being that, since this function applies to all types of callbacks, the type of ``callback`` is ``void *``.
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Note in particular that the value of ``userData`` will need to match with the call that was used to register the callback. If you are having trouble, double check the value of ``userData``.
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The ``eventTypeId`` represents the event type, the same Id received in the callback functions.
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The function returns ``EMSCRIPTEN_RESULT_SUCCESS`` when the event handler callback is removed and ``EMSCRIPTEN_RESULT_INVALID_PARAM`` otherwise.
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.. code-block:: cpp
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// Example
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bool my_mouse_callback_1(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData) {
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// ...
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}
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bool my_mouse_callback_2(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData) {
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// ...
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}
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void main() {
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// 1. set callbacks for mouse down and mouse move
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emscripten_set_mousedown_callback("#mydiv", 0, my_mouse_callback_1);
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emscripten_set_mousedown_callback("#mydiv", (void *) 34, my_mouse_callback_2);
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emscripten_set_mousemove_callback("#mydiv", 0, my_mouse_callback_1);
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// 2. remove these callbacks
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emscripten_html5_remove_event_listener("#mydiv", 0, EMSCRIPTEN_EVENT_MOUSEDOWN, my_mouse_callback_1);
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emscripten_html5_remove_event_listener("#mydiv", (void *) 34, EMSCRIPTEN_EVENT_MOUSEDOWN, my_mouse_callback_2);
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emscripten_html5_remove_event_listener("#mydiv", 0, EMSCRIPTEN_EVENT_MOUSEMOVE, my_mouse_callback_1);
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}
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Callback functions
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------------------

‎src/lib/libhtml5.js‎

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@@ -201,6 +201,19 @@ var LibraryHTML5 = {
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return {{{ cDefs.EMSCRIPTEN_RESULT_SUCCESS }}};
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},
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removeSingleHandler(eventHandler) {
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for (var [i, handler] of JSEvents.eventHandlers.entries()) {
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if (handler.target === eventHandler.target
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&& handler.eventTypeId === eventHandler.eventTypeId
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&& handler.callbackfunc === eventHandler.callbackfunc
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&& handler.userData === eventHandler.userData) {
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JSEvents._removeHandler(i);
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return {{{ cDefs.EMSCRIPTEN_RESULT_SUCCESS }}};
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}
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}
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return {{{ cDefs.EMSCRIPTEN_RESULT_INVALID_PARAM }}};
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},
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#if PTHREADS
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getTargetThreadForEventCallback(targetThread) {
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switch (targetThread) {
@@ -291,6 +304,8 @@ var LibraryHTML5 = {
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var eventHandler = {
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target: findEventTarget(target),
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: keyEventHandlerFunc,
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useCapture
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},
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#endif
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emscripten_html5_remove_event_listener__proxy: 'sync',
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emscripten_html5_remove_event_listener__deps: ['$JSEvents', '$findEventTarget'],
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emscripten_html5_remove_event_listener: (target, userData, eventTypeId, callback) => {
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var eventHandler = {
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target: findEventTarget(target),
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userData,
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eventTypeId,
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callbackfunc: callback,
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};
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return JSEvents.removeSingleHandler(eventHandler);
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},
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emscripten_set_keypress_callback_on_thread__proxy: 'sync',
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emscripten_set_keypress_callback_on_thread__deps: ['$registerKeyEventCallback'],
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emscripten_set_keypress_callback_on_thread: (target, userData, useCapture, callbackfunc, targetThread) =>
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allowsDeferredCalls: eventTypeString != 'mousemove' && eventTypeString != 'mouseenter' && eventTypeString != 'mouseleave', // Mouse move events do not allow fullscreen/pointer lock requests to be handled in them!
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#endif
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: mouseEventHandlerFunc,
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useCapture
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allowsDeferredCalls: true,
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#endif
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: wheelHandlerFunc,
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useCapture
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var eventHandler = {
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target,
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: uiEventHandlerFunc,
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useCapture
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var eventHandler = {
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target: findEventTarget(target),
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: focusEventHandlerFunc,
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useCapture
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var eventHandler = {
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target: findEventTarget(target),
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: deviceOrientationEventHandlerFunc,
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useCapture
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var eventHandler = {
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target: findEventTarget(target),
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: deviceMotionEventHandlerFunc,
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useCapture
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var eventHandler = {
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target,
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: orientationChangeEventHandlerFunc,
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useCapture
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var eventHandler = {
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target,
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: fullscreenChangeEventhandlerFunc,
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useCapture
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var eventHandler = {
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target,
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: pointerlockChangeEventHandlerFunc,
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useCapture
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var eventHandler = {
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target,
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: pointerlockErrorEventHandlerFunc,
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useCapture
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var eventHandler = {
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target,
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: visibilityChangeEventHandlerFunc,
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useCapture
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allowsDeferredCalls: eventTypeString == 'touchstart' || eventTypeString == 'touchend',
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#endif
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: touchEventHandlerFunc,
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useCapture
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allowsDeferredCalls: true,
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#endif
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: gamepadEventHandlerFunc,
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useCapture
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var eventHandler = {
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target: findEventTarget(target),
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: beforeUnloadEventHandlerFunc,
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useCapture
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var eventHandler = {
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target: battery,
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: batteryEventHandlerFunc,
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useCapture

‎src/lib/libhtml5_webgl.js‎

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@@ -440,6 +440,8 @@ var LibraryHtml5WebGL = {
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var eventHandler = {
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target: findEventTarget(target),
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eventTypeString,
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eventTypeId,
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userData,
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callbackfunc,
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handlerFunc: webGlEventHandlerFunc,
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useCapture

‎src/lib/libsigs.js‎

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emscripten_has_threading_support__sig: 'i',
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emscripten_hide_mouse__sig: 'v',
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emscripten_html5_remove_all_event_listeners__sig: 'v',
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emscripten_html5_remove_event_listener__sig: 'ippip',
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emscripten_idb_async_clear__sig: 'vpppp',
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emscripten_idb_async_delete__sig: 'vppppp',
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emscripten_idb_async_exists__sig: 'vppppp',

‎system/include/emscripten/html5.h‎

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@@ -420,6 +420,8 @@ EMSCRIPTEN_RESULT emscripten_get_element_css_size(const char *target __attribute
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void emscripten_html5_remove_all_event_listeners(void);
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EMSCRIPTEN_RESULT emscripten_html5_remove_event_listener(const char *target __attribute__((nonnull)), void *userData, int eventTypeId, void *callback __attribute__((nonnull)));
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#define EM_CALLBACK_THREAD_CONTEXT_MAIN_RUNTIME_THREAD ((pthread_t)0x1)
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#define EM_CALLBACK_THREAD_CONTEXT_CALLING_THREAD ((pthread_t)0x2)
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‎test/codesize/test_codesize_hello_dylink_all.json‎

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{
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"a.out.js": 245421,
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"a.out.js": 245799,
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"a.out.nodebug.wasm": 574167,
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"total": 819588,
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"total": 819966,
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"sent": [
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"IMG_Init",
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"IMG_Load",
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"emscripten_has_asyncify",
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"emscripten_hide_mouse",
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"emscripten_html5_remove_all_event_listeners",
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"emscripten_html5_remove_event_listener",
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"emscripten_idb_async_clear",
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"emscripten_idb_async_delete",
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"emscripten_idb_async_exists",

‎test/test_browser.py‎

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self.cflags.append('--pre-js=pre.js')
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self.btest_exit('test_html5_core.c', cflags=opts)
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def test_html5_remove_event_listener(self):
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self.btest_exit('test_html5_remove_event_listener.c')
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@parameterized({
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'': ([],),
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'closure': (['-O2', '-g1', '--closure=1'],),

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