How to generate a wasm library for reuse

[hsauro]

I can't figure out how to generate a reusable wasm library. If I use the library or template unit I get errors from Zig. I use the program template I get an executable which can't be resused. I suspect its because the call to zig is

compile lib simpleLib_wasm Debug wasm32-wasi 2 errors

when for libraries it should be something like

compile lib simpleLib_wasm Debug wasm32-freestanding 2 errors

[jarroddavis68]

Full support for wasm is coming. At the moment it is optimized for desktop. Here are something thing to keep in mind:

A few C++/runtime features must be trimmed for WASM. Our runtime currently uses std::fstream. On WASM, there’s no real filesystem (and in many libc++ WASI builds the <fstream> types are intentionally incomplete), so std::basic_fstream is undefined.

1. Use wasm32-wasi (32-bit). WASM64 is still experimental.

2. Remove:

   • std::fstream / file I/O (use memory buffers or host callbacks instead)
   • threads/atomics, locales, newlocale, timeBeginPeriod/WinMM, etc.
   • any OS APIs and console tricks beyond basic printf on preopened dirs.

3. Exported functions: generated symbols are exported as C-style functions. For WASM, we mark them extern "C" with default visibility so the linker keeps them. In the library use {$ABI C}

4. Exceptions/RTTI: disabled in WASM mode for now. This is an example of trimming that will need to be done, we would need to turn this off, which enabled by default.

5. Linking: build a WASM “shared” lib and export your public entry points.

6. Avoid any Pascal APIs that end up touching files/threads in WASM builds (I’ll document the allowed subset). Use in-memory streams and caller-supplied buffers.

7. If you need filesystem access under WASI, we’ll rely on preopened directories and very limited stdio; browsers (wasm32-unknown) won’t have files at all.

We will have to provide better support when targeting wasm by trimming what we can automatically, and you will have to keep the rest in mind manually when you are using wasm. Right now, JetPascal is designed around 64-bit executables, while stable WASM is still 32-bit. WASM64 is still experimental, but once it matures it’ll align much better with our architecture. Better WASM support is planned for future updates as the platform stabilizes, and we adapt the runtime accordingly.

[jarroddavis68]

Have not tested this, maybe you can do:
jet zig -fno-exceptions -fno-rtti build and see if will disable rtti and exceptins