Hi David,I don't think is an issue of warning, even if I apply your patch I have the same error, see: https://imgur.com/a/pYcLLWx To reproduce the bug: Be on  Big Sur 11.6.3 (20G415) https://support.apple.com/en-us/HT213055Download Pharo 8: curl https://get.pharo.org/64/80+vm|bash Open the image and evaluate ina playground:Metacello new   configuration: 'OSProcess';   repository: 'http://www.squeaksource.com/MetacelloRepository';  load . and then (PipeableOSProcess command: 'ps')  output. The bug will show itself CheersDavide On Friday, February 4, 2022, 04:39:28 PM GMT+1, David T. Lewis <lewis@mail.msen.com> wrote: Hi Davide, Actually the warning has been removed in newer versions of OSProcess. I do not have time to do an update for Pharo now, but in the mean time you can apply this change in your image to remove the notifier: AioEventHandler>>initializeForExceptions: exceptionEventFlag readEvents: readEventFlag writeEvents: writeEventFlag    semaphore := Semaphore new.    semaIndex := Smalltalk registerExternalObject: semaphore.    (AioPluginPresent = true) ifTrue: [       ([self aioEnable: self descriptor forSemaphore: self semaIndex externalObject: true]          on: Warning          do: [:e |             self close. "unregister the semaphore"             OSProcess trace: e messageText asString. nil])          ifNotNil:             [handlerProc := self                handleExceptions: exceptionEventFlag                readEvents: readEventFlag                writeEvents: writeEventFlag]] HTH, Dave On Fri, Feb 04, 2022 at 03:05:57PM +0000, Davide Varvello wrote:
 Hi David,That's weird because if the AioPlugin is not present in my VM,??PipeableOSProcess shouldn't have worked till this morning... when I upgraded my mac :-) The warning is not skippable, it stops me at:??MessageNotUnderstood: IRJump>> #nextBytecodeOffsetAfterJumpCheersDavide
  On Friday, February 4, 2022, 03:54:59 PM GMT+1, David T. Lewis <lewis@mail.msen.com> wrote:   On Fri, Feb 04, 2022 at 01:46:46PM +0000, Davide Varvello via Pharo-users wrote:
Hi guys, Suddenly evaluating a simple: (PipeableOSProcess command: 'ps') output, or any other PipeableOSProcess command, Pharo gives me: "aio event forwarding not supported". I guess it is something related to the latest update of the OS, specifically Big Sur 11.6.3 (20G415) https://support.apple.com/en-us/HT213055I'm on a Mac, of course, Pharo 8.0.0, Build information: Pharo-8.0.0+build.1128.sha.9f6475d88dda7d83acdeeda794df35d304cf620d (64 Bit) Can you help me, please?CheersDavide
Hi Davide,
The warning message indicates that the AioPlugin is not present in your VM. I do not know the reason for that, although your PipeableOSProcess should still work if you proceed through the warning.
Dave
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