[Cuis-dev] problems in OSProcess

David T. Lewis lewis at mail.msen.com
Fri Oct 15 16:32:36 PDT 2021

On Fri, Oct 15, 2021 at 04:52:22PM +0200, Nicola Mingotti via Cuis-dev wrote:
> Hi guys,
> I think there was a problematic change somewhere in OSProcess
> ----- up to 4-5 days ago image this was ok ----
> ExternalUnixOSProcess command: ' ls -la '.???????????? # works
> PipeableOSProcess waitForCommand: 'ls -la' .???????? # works
> ----- today updated Cuis-Smalltalk-Dev ----
> ExternalUnixOSProcess command: ' ls -la '.?????????? # works
> PipeableOSProcess waitForCommand: 'ls -la' .?????? # does not work
> => warning: aio event forwarding not supported
> => If i proceed I get this error: https://pasteboard.co/HFvroC7n6eEz.png
> . CommandShell was not changed, so i suppose it was a change in Cuis

Hi Nicola,

I cannot reproduce this problem, but there are two things that
seem strange to me here.

First, the emergency evaluator seems to be showing that an
instance of PipeableOSProcess does not understand the message
#inspectorClass. But #inspectorClass is implemented in Object
and PipeableOSProcess inherits from Object so this does not
seem possible. Can you check and make sure that the hierarchy
looks right? Maybe there was some problem in the way that the
CommandShell package was loaded in your image.

Second, the 'warning: aio event forwarding not supported' is
a warning to tell you AioPlugin is not present in the VM.
AioPlugin is not required, but some OSProcess/CommandShell
functions may be less responsive if it is not there, hence the
warning message. For most Unix VMs, the AioPlugin is present (see
'Smalltalk listBuiltInModules' and 'Smalltalk listLoadedModules'
to check). So maybe you are running a different VM, or perhaps
the problem with PipeableOSProcess class hierarchy is somehow
causing the primitive to fail. I am not sure, but I suspect
some issue related to the way the CommandShell package was


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