can't inferre task return type.

[bung87]

cmd: nim c -d:ChronosAsync --threads:on tests/tstreamserver.nim

https://github.com/bung87/scorper/blob/36aa15fc662718c07065306c0c95b735763c47f1/src/scorper/http/streamserver.nim#L858

when MultiThreads:
      let retry = await req.server.pool.spawn processRequest(req)

Error: type mismatch: got <RetTypegensym817>`

[Clonkk]

This is caused by your proc being async.

See https://github.com/yglukhov/asyncthreadpool/issues/5

Use non-async proc for expected results

[bung87]

I now cast types, but still asyncthreadpool not work as I expected.

[Clonkk]

I don't understand what value you want to cast.

The issue comes from the compiler handling return type of async proc differently.

Change processRequest definition and remove the async and it should be fine :

proc processRequest(
  req: Request,
): Future[bool] {.async.} =

The underlying question (and perhaps I shouldn't have closed my issue) is should a threadpool be able to handle async proc ? It's not obvious that it should but you'd want @yglukhov thoughts on the matter.

[bung87]

the readme clam use await for async proc , while the return type cant inferred , in this case assign the returns to variable a , when I call if a, if will trigger type doesn't match, so I casting it, I still get copyAux error when channel send back , like I did tried use threads and channels without asyncthreadpool. no magic lib just like go's go routine that I only need call go some proc.

[yglukhov]

The spawned proc has to be synchronous. Whatever it returns is then wrapped into future by the threadpool.

[Clonkk]

Note: in async functions you should use await instead of waitFor.

I think this sentence in the Readme is what @bung87 is referring to.

It should be clarified whether or not async works with thread pool

[yglukhov]

Maybe the readme is confusing, let me explain.

• The spawned proc should not be async.
• We wait for the spawned proc result in async manner. That is either await or waitFor depending if you're spawning from within an async proc or not.
• The spawned proc can surely run async stuff within itself, using (e.g.) waitFor.

Does that make sense?

[bung87]

much clear, thanks!

[yglukhov]

Feel free to add to the readme, if needed