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Fixed in 2020.1.X

Fixed in 2019.2.X, 2019.3.X



Found in





Issue ID




[WebGL] Building fails with Emscripten's Python failure



To reproduce:
1) Open the attached project
2) Build it for WebGL

It fails with the following error: Failed running "E:\Stale Unities\2019.1\2019.1.0f2_f38a641b93e7\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten_Win\python\\python.exe" -E "E:\Stale Unities\2019.1\2019.1.0f2_f38a641b93e7\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\emcc" @"E:\Downloads\case_1161712-Snail_Paradise\Assets\..\Temp\emcc_arguments.resp"

stderr:warning: unexpected number of arguments 1 in call to '__cxa_pure_virtual', should be 0warning: unexpected number of arguments 2 in call to '_ZN6il2cpp6icalls8mscorlib6System6String22RedirectToCreateStringEv' <..>

Not reproduced in 2019.2.0a3, 2019.1.0b4, 2018.4.2f1
Reproduced in 2019.2.0a6, 2019.1.0b5, 2019.3.0a6

  1. Resolution Note (fix version 2020.1):

    Fixed in 2020.1.0a17, 2019.3.0f1, 2019.2.15f1

Comments (7)

  1. otis5842

    Aug 01, 2022 07:32

    EMSCRIPTEN can be buggy. And it's not just the new web GL version which is causing issues, but also the legacy version of EMSCRIPTEN. The latest versions (1.1 and higher) of EMSCRIPTEN have a built-in support for web GL, but this does not mean that other versions will work. In fact, it can even break your build!

  2. Gnoktade

    Dec 26, 2020 13:48

    I'm using 2019.2.1 but I've had a problem Uncaught abort("To use dlopen, you need to use Emscripten's linking support, see") at Error

  3. aklyuchev

    Nov 21, 2019 14:49

    i don't use PlayFab SDK
    but have similar issue on unity 2019.2.12f1

  4. jukka_j

    Oct 05, 2019 08:17

    This bug report does not reference PlayFab SDK, but based on and, I assume this bug report is about the detected breakage with respect to PlayFab SDK.

    A proper fix is being worked on. Meanwhile, when this error occurs with respect to using the PlayFab SDK, there is a potential workaround that one can add an Editor script to the build that executes

    PlayerSettings.WebGL.emscriptenArgs = "-s ERROR_ON_UNDEFINED_SYMBOLS=0";

    before running the build.

    If your project is not using the PlayFab SDK, and you are receiving an Emscripten python failure, please open a different bug report, since the root cause is definitely something else. (receiving a python error from Emscripten is a general "compiler aborted" message, that does not yet identify the actual cause of the abort)

  5. goldbug

    Sep 30, 2019 18:07

    It has been 3 months, this particular bug causes playfab webgl not to work on 2019.2.x

    Can we get an update please? Why such large lead time?

  6. toddbellMSFT

    Sep 25, 2019 23:04

    Reproduced in 2019.2.6f1

  7. irfan_qvady

    Jul 18, 2019 07:49

    Reproduced in 2019.1.1f1

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