[racket-dev] online check syntax deadlock: can you help?

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Thu Sep 1 09:36:27 EDT 2011

[[ FWIW, I have been running drracket like this for a couple of weeks and have had no problem. Mac OS X 10.6.8 ]]

On Sep 1, 2011, at 8:34 AM, Matthew Flatt wrote:

> At Wed, 31 Aug 2011 23:00:25 -0700, John Clements wrote:
>> On Aug 31, 2011, at 5:08 PM, Robby Findler wrote:
>>> I've been seeing for some time now a deadlock in online check syntax.
>>> That is, after a while it just gets stuck and fails to complete the
>>> online check syntax. Typically what you see is the little blue dot
>>> come on but the cpu load drop to zero without any check syntax arrows
>>> ever showing up.
>>> Matthew and I have fixed a few things that could lead to these
>>> symptoms and I've just now pushed a change to compiler/cm to add some
>>> more informative logging.
>>> So: if you have the energy, can you please run DrRacket like this:
>>> racket -W info -l- drracket
>> This doesn't work at all for me on the Mac, and highlights a problem that I've 
>> had at other times with racket & GUI frames: none of the keyboard input goes 
>> to the window.
>> Specifically, here's the sequence of events:
>> 1) run racket -W info -l- drracket
>> 2) See splash window come up, *underneath* terminal window and not given focus.
>> 3) See DrRacket frame come up, again without focus.
>> 4) Click on DrRacket frame, it gets focus and I see the cursor blinking.
>> 5) Type a few characters -- they don't show up in DrRacket. Instead, they go 
>> to the terminal window.
>> Furthermore, there's no DrRacket menu bar, and no DrRacket icon in the cmd-tab 
>> list.
>> 6) Go back to terminal window, use ctrl-\ to blow it away.
>> Is that expected? It looks like the OS is preventing 
>> not-full-fledged-app-things from opening windows and handling input. This is 
>> OS 10.6,8.
> The code that is supposed to make the process a full-fledged app is
> line at line 81 of "collects/mred/private/cocoa/queue.rkt":
> ;; In case we were started in an executable without a bundle,
> ;; explicitly register with the dock so the application can receive
> ;; keyboard events.
> (define-cstruct _ProcessSerialNumber
>   ([highLongOfPSN _ulong]
>    [lowLongOfPSN _ulong]))
> (define kCurrentProcess 2)
> (define kProcessTransformToForegroundApplication 1)
> (define-appserv TransformProcessType (_fun _ProcessSerialNumber-pointer
>                                            _uint32
>                                            -> _OSStatus))
> (void (TransformProcessType (make-ProcessSerialNumber 0 kCurrentProcess)
>                             kProcessTransformToForegroundApplication))
> Note that the code ignores the result of `TransformProcessType', which
> is a bad idea. If you remove the `void' wrapper, what number result
> gets printed on your machine?
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