WebGL build fails in Unity 6000.5: undefined symbols saveSetjmp and testSetjmp

[shlafin]

Environment

• UniText: 1.0.0
• Unity: 6000.5.2f1
• Platform: WebGL
• Operating system: macOS
• Native library: Plugins/WebGL/libunitext_native.a

Problem

A WebGL build fails during the final Emscripten linking stage because libunitext_native.a references legacy setjmp/longjmp symbols that are unavailable in the Emscripten toolchain bundled with Unity 6000.5.

The original error is:

Library/Bee/artifacts/WebGL/build/debug_WebGL_wasm/build.js:
undefined symbol: saveSetjmp
(referenced by root reference (e.g. compiled C/C++ code))

Library/Bee/artifacts/WebGL/build/debug_WebGL_wasm/build.js:
undefined symbol: testSetjmp
(referenced by root reference (e.g. compiled C/C++ code))

Aborting compilation due to previous errors

I verified that libunitext_native.a contains references to both saveSetjmp and testSetjmp.

Tests performed

Unity 6000.5 with WebAssembly 2023 enabled

The build fails with:

undefined symbol: saveSetjmp
undefined symbol: testSetjmp

Adding:

-sSUPPORT_LONGJMP=emscripten

results in:

emcc: error: SUPPORT_LONGJMP=emscripten is not compatible with -fwasm-exceptions

Unity enables native WebAssembly exceptions when WebAssembly 2023 is enabled, while the supplied UniText library appears to depend on the legacy Emscripten setjmp/longjmp implementation.

Unity 6000.5 with WebAssembly 2023 disabled

Using:

-sSUPPORT_LONGJMP=emscripten

still fails with:

undefined symbol: saveSetjmp
undefined symbol: testSetjmp

Therefore, disabling WebAssembly 2023 is not sufficient in Unity 6000.5.

Unity 6000.3

The project builds successfully in Unity 6000.3 with:

Enable WebAssembly 2023: Disabled
Emscripten Arguments: -sSUPPORT_LONGJMP=emscripten

This suggests that the Emscripten/LLVM update between Unity 6000.3 and Unity 6000.5 removed or changed the legacy internal functions used by the current precompiled library.

Expected behavior

UniText 1.0.0 should build for WebGL using current Unity 6 versions, including Unity 6000.5, without requiring deprecated internal Emscripten symbols.

Request

Could you please provide a version of libunitext_native.a rebuilt with the Emscripten toolchain bundled with Unity 6000.5, preferably using the current WebAssembly exception and longjmp model?

It would also be helpful to document:

• which Unity versions the supplied WebGL library supports;
• whether WebAssembly 2023 should be enabled or disabled;
• whether any custom Emscripten arguments are required.

Thank you.

[LightSideMeowshop]

Hi! Thank you for your report! UniText 1.0.0 is not supported by me it's supporting by community.

the free version (this GitHub open-source version) is positioned as a bare-bones text engine without the huge number of additional features and improvements. It's simply impossible to list everything, but as of right now, UniText 3.0.0 is the most up-to-date, actively maintained product

all changes can be viewed here:
https://unity.lightside.media/en/unitext/changelog - changes between 1.0.0 and 2.12.12
https://unity.lightside.media/en/unitext/changelog/next - changes between 2.12.12 and 3.0.0

But in brief:

1. Large-scale performance optimization
2. Improved rendering and glyph quality, 2x lower RAM usage thanks to eliminating the CPU-side atlas copy, granular atlas updates performed directly on the GPU
3. Full, extended Font Family support
4. Full, extended support for word segmentation in languages not covered by UAX#14, such as Thai, Khmer, Lao, Myanmar, and CJ
5. Editable text, selectable text, the ability to create input fields, context menu support, support for all clipboard channels
6. Extended API, improved system of styles, modifiers, and rules
7. A layers-and-paints system that lets you create color, texture, and gradient paints, which can paint any area of the text: face, outline, shadow
8. A granular modifier-property update system that makes it possible to animate any parameter from code
9. Extended language support
10. A system fonts implementation that allows displaying absolutely any character in the world without needing to add fonts to the project. You can even ship without a single font - fonts are loaded directly from the system the build is installed on
11. A huge number of new modifiers, animations, and effects added
12. A batcher for world-space text that merges all UniTextWorld instances into a single draw call

and all of this probably doesn't even cover 5% of what has been added, improved, changed, and fixed. I just tried to recall things from memory right now, but honestly, I can't describe everything in a single message

[shlafin]

Thank you for the clarification.

Since the open-source version is no longer actively maintained, I ended up implementing and rebuilding the WebGL native library myself so I could continue using UniText 1.0.0 with Unity 6000.5.2f1 and WebAssembly 2023.

The original libunitext_native.a references legacy Emscripten symbols such as saveSetjmp and testSetjmp, which are no longer available in the current Unity WebGL toolchain.

I created a compatible implementation of the native ut_* ABI using HarfBuzz 12.3.2 and FreeType 2.14.3. HarfBuzz, FreeType, and the UniText wrapper are combined into a single LLVM module, with all internal symbols hidden to prevent conflicts with the versions bundled with Unity.

I also had to reproduce the glyph rendering path expected by UniText:

grayscale glyph rendering through FreeType;

SDF generation using an Euclidean Distance Transform;

correct padding and glyph metrics;

vertical bitmap conversion for Unity’s atlas layout.

The resulting library now builds successfully with Unity 6000.5.2f1, WebAssembly 2023 enabled, and no legacy SUPPORT_LONGJMP workaround. I tested it with all 20 languages used by my game, including Arabic, Devanagari, Bengali, Gujarati, Tamil, Telugu, Kannada, Malayalam, Japanese, Korean, and Chinese.

I am attaching the rebuilt libunitext_native.a.zip in case it is useful to other users.

One suggestion for the open-source version: providing only a precompiled WebGL archive is quite fragile because Emscripten/LLVM bitcode and WebAssembly object files may not remain compatible across Unity versions and toolchain updates. A precompiled archive is not inherently wrong, but it would be much more reliable to also provide the native source code, build instructions, and a compatibility matrix for supported Unity versions.

The attached archive was built specifically with the Unity 6000.5.2f1 WebGL toolchain, so I cannot guarantee compatibility with older Unity versions. Ideally, users should be able to rebuild it using the toolchain bundled with their Unity version.

I hope this information and the rebuilt library can help other users of the community-supported version.

libunitext_native.a.zip

[LightSideMeowshop]

thank you so much❤️ yes, you are right I have to add the native code which builds the native libs but for this time I don't have enough time for it. Actually almost every user use UniText Folio 3.0.0 for their products because of stability, performance, quality, convenience and extremely large number of features. UniText Folio 3.0.0 contains over 120K lines of the pure C# code while UniText 1.0.0 has only 30K

I don't recommend to use UniText 1.0.0 for the real/commercial products only for pet-projects

[shlafin]

I completely understand your position regarding the open-source version and UniText Folio 3.0.0.

I also want to say that UniText is a genuinely impressive project. Proper multilingual text rendering is still a difficult and underserved area in Unity, especially for projects that need Arabic, Indic scripts, CJK languages, emoji, and high-quality text rendering in the same application. A solution like UniText is extremely valuable to the Unity developer community.

History sometimes has a way of repeating itself. TextMeshPro also started as an independent project and eventually became such an important part of the Unity ecosystem that it was acquired by Unity Technologies and integrated into the engine.

I would not be surprised if UniText followed a similarly successful path one day. It solves a real problem that Unity developers continue to face, and I believe this technology deserves wider recognition and adoption.

Thank you for creating it and for all the work you have invested in the project.

[LightSideMeowshop]

awwwww😭😭😭 thank you so muchhhhhhhhhhh❤️ I spent 11 months of my life for UniText 1.0.0 and I was proud of it, but now I am ashamed of this version😅

and I spent +8 months of my life for UniText Folio 3.0.0. No days off

[LightSideMeowshop]

For this time UniText is a biggest package on the Unity Asset Store comparing an amount of the pure C# code

[shlafin]

That is an incredible amount of work — 19 months with no days off. I sincerely hope UniText remains useful and in demand for many years

I sometimes worry that Unity may eventually replace uGUI with UI Toolkit, especially now that UI Toolkit has multilingual text shaping through HarfBuzz, ICU, and FreeType. Fortunately, Unity has not announced the deprecation of uGUI and says it will remain supported until UI Toolkit becomes a complete replacement.

As far as I understand, UniText currently targets uGUI and world-space rendering rather than UI Toolkit. Still, uGUI has an enormous ecosystem and countless commercial projects, so I believe your work will remain valuable for a very long time.