Is it ok to Module.callMain with ASYNCIFY?

[iliakan]

I've read in the docs that one should use ccall with -sASINCIFY to call a C function that has nested async calls.

Does it mean that Module.callMain shouldn't be used with ASYNCIFY, and I should replace it with ccall?

P.S. I use callMain and I get Uncaught (in promise) ExitStatus {name: 'ExitStatus', message: 'Program terminated with exit(0)', status: 0}, originating from _proc_exit, after callMain completes.

[iliakan]

So to say, callMain did work for a simple case, but gave that error.

I tried to replace await Module.callMain(args) with await Module.ccall("main", "number", ["number", "number"], [argc, argv], {async: true}).

It again kind of works, but there's the error is somewhere in the middle:

program exited (with status: 0), but keepRuntimeAlive() is set (counter=1) due to an async operation, 
so halting execution but not exiting the runtime or preventing further async execution 
(you can use emscripten_force_exit, if you want to force a true shutdown)

Does it mean I forgot to insert await somewhere? Any clue? ;)

[sbc100]

I don't think that log message is anything to worry about.. we should probably not display it by default.

[iliakan]

Did I get it right that await Module.callMain is a bad thing?
There's some async magic in ccall, but really not sure how important it is.

[iliakan]

I removed -O0, and now every await Module.ccall throws an exception:

Uncaught (in promise) ExitStatus {name: 'ExitStatus', message: 'Program terminated with exit(0)', status: 0}

Am I supposed to wrap every await Module.ccall into try/catch and silence such exceptions?

[sbc100]

callMain is really an internal function for emscripten. Normally it is run by run function. callMain takes case of calling your main function and also shutting down the runtime after main returns. The last thing is does is call exitJS which is turn calls proc_exit which will throw ExitStatus.

See src/library.js for the definitions of these various functions.

So yes, anyone that calls main or callMain should be prepared to handle the ExitStatus exception. Its now an emscripten program terminates itself and unwinds the stack.

[sbc100]

Actually calling in Module export all could result in ExitStatus being thrown, so one always needs to be prepared to handle that I guess.

[iliakan]

Thank you. The ExitStatus exception was getting out only with ASYNCIFY for me.

Isn't it specifically made for async code?