Trouble getting started with WebAssembly + QtWidgets (c++, Windows)

[Tom Sirgedas]

I create desktop QtWidget apps, but I'm interested in putting my work on the web.

I'm not too familiar with command-line building, so I might be making an obvious mistake.

For now I'm just trying to build a bare-bones CPP and failing. Should I be using cmake instead?

C:\Git\wasm_test>C:\Git\emsdk\emsdk_env.bat
Setting up EMSDK environment (suppress these messages with EMSDK_QUIET=1)
Adding directories to PATH:
PATH += C:\Git\emsdk
PATH += C:\Git\emsdk\upstream\emscripten
PATH += C:\Git\emsdk\node\14.18.2_64bit\bin

Setting environment variables:
PATH = C:\Git\emsdk;C:\Git\emsdk\upstream\emscripten;C:\Git\emsdk\node\14.18.2_64bit\bin;  (...)
EMSDK = C:/Git/emsdk
EMSDK_NODE = C:\Git\emsdk\node\14.18.2_64bit\bin\node.exe
EMSDK_PYTHON = C:\Git\emsdk\python\3.9.2-nuget_64bit\python.exe
JAVA_HOME = C:\Git\emsdk\java\8.152_64bit
Clearing existing environment variable: EMSDK_PY

C:\Git\wasm_test>D:\Qt6\6.4.2\wasm_32\bin\qmake -o Makefile hello4.pro
Project MESSAGE: Setting INITIAL_MEMORY to 50MB

C:\Git\wasm_test>emmake make
make: make
em++ -c -O2 -std=gnu++1z -Wall -Wextra -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -I. -ID:/Qt6/6.4.2/wasm_32/include -ID:/Qt6/6.4.2/wasm_32/include/QtGui -ID:/Qt6/6.4.2/wasm_32/include/QtCore -I. -I/.emscripten_ports/openssl/include -ID:/Qt6/6.4.2/wasm_32/mkspecs/wasm-emscripten -o hello4.obj hello4.cpp
/cygdrive/c/Git/emsdk/upstream/emscripten/em++: line 36: exec: C:\Git\emsdk\python\3.9.2-nuget_64bit\python.exe: not found
make: *** [Makefile:655: hello4.obj] Error 127
emmake: error: 'make' failed (returned 2)

The error is weird, because python.exe exists at that path:

C:\Git\wasm_test>C:\Git\emsdk\python\3.9.2-nuget_64bit\python.exe
Python 3.9.2 (tags/v3.9.2:1a79785, Feb 19 2021, 13:44:55) [MSC v.1928 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>

[lorn.potter]

You need to install ninja and use that to build.
MSVC compiler and Emscripten don't mix well.