Would it be a good idea to expose an async as well as a sync version of the exported functions?

[Amatewasu]

I don't know how other people use emscripten but when I call a C function from JS, most of the time the function is quite "heavy" (at least a few ms). I use it a bit like a backend. So in this case I don't want to block my JS main thread.

I mean, an option to expose a synchronous version as well as an asynchronous version of the exported function could be a good idea. Thereby, in the JS code, when we want to block the JS main thread we use the synchronous version, and want we want a Promise we use the asynchronous version.

Of course, it would increase the output but I think it could be ok.

[Amatewasu]

Maybe the solution would simply to enable -sASYNCIFY by default. Thereby one could either call MyWasmModule.ccall('heavy_stuff_1', [], [], [], { async: true }); or MyWasmModule.ccall('heavy_stuff_1', [], [], [], { async: false}); depending of its need?

[sbc100]

In your example, where would heavy_stuff_1 run if not on the main thread? Are you perhaps imagining scheduling the work on a background thread?

[Amatewasu]

Yeah I agree, it is likely way better to call the function from a worker. It is just that I expected the wasm VM to act a bit like a worker.

[sbc100]

Yeah, wasm can't do that on its own. Unless you run it in worker any actual work will always block them main thread for as long as it runs.

[Amatewasu]

Alright, thank you a lot for the explanation. Thereby, the feature idea is useless. Have a nice day. :)