I am not sure Qt signals would work. You should certainly be able to so callbacks though.

It is possible to call c/c++ functions from javascript as well as call javascript from c/c++. Look at https://emscripten.org/docs/porting/connecting_cpp_and_javascript/Interacting-with-code.html

You need to export those by adding linker arguments: https://emscripten.org/docs/porting/connecting_cpp_and_javascript/Interacting-with-code.html#interacting-with-code-ccall-cwrap

I just saw that a QNetworkReply::TimeoutError code exists. Shouldn't this code be set when a timeout occurred ? Is this a bug or did I misunderstand something ?

@lorn-potter Thanks for getting back to me! I'm trying to build this project: https://github.com/herewegoblueno/cs1230-final Just to provide context, this works well when built for Mac. And yes I am importing GL/glew.h myself. Also by the way I've also noticed that the compilers don't recognize the standard libraries like <vector>, <map>, etc (or maybe that's just the static checker? not sure if those will result in compile time errors since I can't build due to glew anyways)

Found the problem: I had installed Qt v 6.0.0 with emscripten 1.39.8. documents say 1.39.8 should work with Qt v5.15.0. Works after installing the correct Qt version.

Problem solved by removing the emrun flag. I can now specify custom arguments in the qtloader.js using emscripten's Module.arguments like this : Module['arguments'] = ['FirstArg', 'SecondArg'];

Hi @SGaist , One thing that made me skeptical about the info on the introduction page, was the affirmative that webassembly doesn't support threads, which is not an absolute true, in fact is relatively simple to enable thread support with the correct emscripten version. But everything so far is telling me that is not possible, or at least it will be very hard to compile wasm as shared.

dunno if you managed to resolve your problem in the meantime, but I had a similar error (under macOS and emscripten 1.39.17): After downloading and installing everything, I ran emsdk_env (which should generate the ~/.emscripten file in the user folder, if I remember correctly) But it seems, that Qt Creator could not resolve the var for the defined emsdk_path emsdk_path = os.path.dirname(os.environ.get('EM_CONFIG')).replace('\\', '/') so I replaced all the placeholder with the explicit path: emsdk_path = '/Users/myuser/Documents/Programming/emsdk' I also added COMPILER_ENGINE = NODE_JS JS_ENGINES = [NODE_JS] at the bottom (not sure though if that was needed) After restarting Qt creator the compiler and toolkit for WebAssembly wer successfully recognized.

Short answer... you can't get the full file path of a file. Your question is more related to safety/security standards regarding major browsers and the decisions related to them made by owner companies/foundations. That is, javascript is not allowed to know the full path of a file shared by the user. So, fileContentReady or in general any webassembly function will end up being a javascript function, limited to the security standards imposed on js implementation by the browser. (You can always ask the user to install a java applet :P )

@lorn-potter you mean if I update part of my application I should download all application in my browser?

@lorn-potter I have checked it in qt 5.15 with em 1.39.16. but still I have same problem.

@Falko said in WebAssembly for Qt Creator: I started with 1.39.8, but Qt Creator was always complaining that I don't use 1.39.7. I updated Qt Creator to the recent version (Qt Creator 4.12.2) but still complains even when I tried to use Emscripten1.39.7!!!

You can, it works with QtQuick.

Well WebAssembly is pretty strict, if you want to make https requests you need to use a proxy/bridge program that translates from websockets to http, it's installed on a PC on the same LAN as the WebAssembly PC (or on the same PC). For example you could use this one: https://github.com/novnc/websockify

@lorn-potter I have installed emsdk using ./emsdk install sdk-fastcomp-1.38.27-64bit ./emsdk activate sdk-fastcomp-1.38.27-64bit bcz installation fails(Error : No such tool/sdk) with ./emsdk install sdk-1.38.16-64bit and using online installer as well as offline static build am getting same error for simple Qt Application build error log kmb@ubuntu:~/Work/FEB2020/TestApp/build$ /home/kmb/Qt/5.14.0/wasm_32/bin/qmake .. Info: creating stash file /home/kmb/Work/FEB2020/TestApp/build/.qmake.stash kmb@ubuntu:~/Work/FEB2020/TestApp/build$ make em++ -c -pipe -O3 -std=gnu++11 -s ALLOW_MEMORY_GROWTH=1 -Wall -Wextra -DQT_DEPRECATED_WARNINGS -DQT_NO_DEBUG -DQT_QUICK_LIB -DQT_GUI_LIB -DQT_QMLMODELS_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -I../../TestApp -I. -I../../../../Qt/5.14.0/wasm_32/include -I../../../../Qt/5.14.0/wasm_32/include/QtQuick -I../../../../Qt/5.14.0/wasm_32/include/QtGui -I../../../../Qt/5.14.0/wasm_32/include/QtQmlModels -I../../../../Qt/5.14.0/wasm_32/include/QtQml -I../../../../Qt/5.14.0/wasm_32/include/QtNetwork -I../../../../Qt/5.14.0/wasm_32/include/QtCore -I. -I/home/kmb/.emscripten_ports/openssl/include -I../../../../Qt/5.14.0/wasm_32/mkspecs/wasm-emscripten -o main.o ../main.cpp em++ -c -pipe -O3 -std=gnu++11 -s ALLOW_MEMORY_GROWTH=1 -Wall -Wextra -DQT_DEPRECATED_WARNINGS -DQT_NO_DEBUG -DQT_QUICK_LIB -DQT_GUI_LIB -DQT_QMLMODELS_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -I../../TestApp -I. -I../../../../Qt/5.14.0/wasm_32/include -I../../../../Qt/5.14.0/wasm_32/include/QtQuick -I../../../../Qt/5.14.0/wasm_32/include/QtGui -I../../../../Qt/5.14.0/wasm_32/include/QtQmlModels -I../../../../Qt/5.14.0/wasm_32/include/QtQml -I../../../../Qt/5.14.0/wasm_32/include/QtNetwork -I../../../../Qt/5.14.0/wasm_32/include/QtCore -I. -I/home/kmb/.emscripten_ports/openssl/include -I../../../../Qt/5.14.0/wasm_32/mkspecs/wasm-emscripten -o testapp.js_plugin_import.o /home/kmb/Work/FEB2020/TestApp/build/testapp.js_plugin_import.cpp em++ -c -pipe -O3 -std=gnu++11 -s ALLOW_MEMORY_GROWTH=1 -Wall -Wextra -DQT_DEPRECATED_WARNINGS -DQT_NO_DEBUG -DQT_QUICK_LIB -DQT_GUI_LIB -DQT_QMLMODELS_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -I../../TestApp -I. -I../../../../Qt/5.14.0/wasm_32/include -I../../../../Qt/5.14.0/wasm_32/include/QtQuick -I../../../../Qt/5.14.0/wasm_32/include/QtGui -I../../../../Qt/5.14.0/wasm_32/include/QtQmlModels -I../../../../Qt/5.14.0/wasm_32/include/QtQml -I../../../../Qt/5.14.0/wasm_32/include/QtNetwork -I../../../../Qt/5.14.0/wasm_32/include/QtCore -I. -I/home/kmb/.emscripten_ports/openssl/include -I../../../../Qt/5.14.0/wasm_32/mkspecs/wasm-emscripten -o testapp.js_qml_plugin_import.o /home/kmb/Work/FEB2020/TestApp/build/testapp.js_qml_plugin_import.cpp /home/kmb/Qt/5.14.0/wasm_32/bin/rcc -name qml ../qml.qrc -o qrc_qml.cpp em++ -c -pipe -O3 -std=gnu++11 -s ALLOW_MEMORY_GROWTH=1 -Wall -Wextra -DQT_DEPRECATED_WARNINGS -DQT_NO_DEBUG -DQT_QUICK_LIB -DQT_GUI_LIB -DQT_QMLMODELS_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -I../../TestApp -I. -I../../../../Qt/5.14.0/wasm_32/include -I../../../../Qt/5.14.0/wasm_32/include/QtQuick -I../../../../Qt/5.14.0/wasm_32/include/QtGui -I../../../../Qt/5.14.0/wasm_32/include/QtQmlModels -I../../../../Qt/5.14.0/wasm_32/include/QtQml -I../../../../Qt/5.14.0/wasm_32/include/QtNetwork -I../../../../Qt/5.14.0/wasm_32/include/QtCore -I. -I/home/kmb/.emscripten_ports/openssl/include -I../../../../Qt/5.14.0/wasm_32/mkspecs/wasm-emscripten -o qrc_qml.o qrc_qml.cpp sed -e s/@APPNAME@/TestApp/g /home/kmb/Qt/5.14.0/wasm_32/plugins/platforms/wasm_shell.html > /home/kmb/Work/FEB2020/TestApp/build/TestApp.html cp -f /home/kmb/Qt/5.14.0/wasm_32/plugins/platforms/qtloader.js /home/kmb/Work/FEB2020/TestApp/build cp -f /home/kmb/Qt/5.14.0/wasm_32/plugins/platforms/qtlogo.svg /home/kmb/Work/FEB2020/TestApp/build em++ -s WASM=1 -s FULL_ES2=1 -s USE_WEBGL2=1 -s NO_EXIT_RUNTIME=0 -s ERROR_ON_UNDEFINED_SYMBOLS=1 --bind -O3 -s ALLOW_MEMORY_GROWTH=1 -o ./TestApp.js main.o testapp.js_plugin_import.o testapp.js_qml_plugin_import.o qrc_qml.o /home/kmb/Qt/5.14.0/wasm_32/plugins/platforms/libqwasm.a /home/kmb/Qt/5.14.0/wasm_32/lib/libQt5EventDispatcherSupport.a /home/kmb/Qt/5.14.0/wasm_32/lib/libQt5FontDatabaseSupport.a /home/kmb/Qt/5.14.0/wasm_32/lib/libqtfreetype.a /home/kmb/Qt/5.14.0/wasm_32/lib/libQt5EglSupport.a /home/kmb/Qt/5.14.0/wasm_32/plugins/imageformats/libqgif.a /home/kmb/Qt/5.14.0/wasm_32/plugins/imageformats/libqicns.a /home/kmb/Qt/5.14.0/wasm_32/plugins/imageformats/libqico.a /home/kmb/Qt/5.14.0/wasm_32/plugins/imageformats/libqjpeg.a /home/kmb/Qt/5.14.0/wasm_32/plugins/imageformats/libqtga.a /home/kmb/Qt/5.14.0/wasm_32/plugins/imageformats/libqtiff.a /home/kmb/Qt/5.14.0/wasm_32/plugins/imageformats/libqwbmp.a /home/kmb/Qt/5.14.0/wasm_32/plugins/imageformats/libqwebp.a /home/kmb/Qt/5.14.0/wasm_32/qml/QtQuick.2/libqtquick2plugin.a /home/kmb/Qt/5.14.0/wasm_32/qml/QtQuick/Window.2/libwindowplugin.a /home/kmb/Qt/5.14.0/wasm_32/lib/libQt5Quick.a /home/kmb/Qt/5.14.0/wasm_32/lib/libQt5QmlModels.a /home/kmb/Qt/5.14.0/wasm_32/lib/libQt5Qml.a /home/kmb/Qt/5.14.0/wasm_32/lib/libQt5Gui.a /home/kmb/Qt/5.14.0/wasm_32/lib/libqtlibpng.a /home/kmb/Qt/5.14.0/wasm_32/lib/libqtharfbuzz.a /home/kmb/Qt/5.14.0/wasm_32/lib/libQt5Network.a /home/kmb/Qt/5.14.0/wasm_32/lib/libQt5Core.a /home/kmb/Qt/5.14.0/wasm_32/lib/libqtpcre2.a shared:ERROR: '/home/kmb/Qtwasm/emsdk/fastcomp-clang/e1.38.27_64bit/binaryen/bin/asm2wasm ./TestApp.temp.asm.js --total-memory=16777216 --trap-mode=allow -O3 --mem-init=./TestApp.js.mem --mem-base=1024 --wasm-only -o ./TestApp.wasm --mvp-features' failed (-9) Makefile:215: recipe for target 'TestApp.js' failed make: *** [TestApp.js] Error 1 so what is cuase here and i am using Ubuntu 18.04 VM kindly let me root cause

Hi Patrick. I'm in the same situation. Installation on archlinux using the official qt5.13 online installer. Android and desktop kits are well configured on qtcreator just by using their respectif qmake. However when I choose the one.of webassembly (wasm_32) distributed by qt, qtcreator warns about the ABI, saying that it is not defined. Its value is unknown-unknown-unknown-..... I compiled a simple qt project using wasm_32 kit but link fails with the following error main.o: architecture machine must be wasm32. Any help?

Oops! It worked in my last attempt, although it look a long time. So, my problem was Emscripten's version after all. Here is the version that worked: emscripten-1.37.1 Note: I've used emsdk to install Emscripten and I had to install a matching LLVM/CLang version: clang-e1.37.1-64bit