unexpected behaviour when grabbing jitter objects in scheduler thread

Timo Rozendal — Wed, 09 Jun 2010 14:40:02 +0000

I encountered some weird behaviour today while grabbing cells from a matrix on in the scheduler thread. After reading http://www.cycling74.com/forums/topic.php?id=3948 I expected the grab work correctly, but to drop messages due to the fact that “All methods for jit.matrix are deferred or usurped when called from a patcher”

however this was not the case, it appeared that the grab started to function as a normal send-object, resulting in output from the matrix itself!

of course, when deferlow-ing the message or using jit.qfaker the behaviour is as expected, but this is not my question here.

– Pasted Max Patch, click to expand. –

Re: unexpected behaviour when grabbing jitter objects in scheduler thread

Rob Ramirez — Mon, 14 Jun 2010 18:05:51 +0000

i believe grab forces events into the high-priority queue, which jitter objects don’t like.
just use deferlow

Re: unexpected behaviour when grabbing jitter objects in scheduler thread

Joshua Kit Clayton — Mon, 14 Jun 2010 18:17:29 +0000

This is *exactly* expected behavior. In the absence of deferlow or queuefaker (the latter which I wouldn’t recommend anyway), we have the following sequence of events:

1. the scheduler message is sent to grab
2. grab sets itself to grab output
3. grab sends the message to jit.matrix
4. jit.matrix defers the message like it is supposed to
5. grab unsets itself from output (this is always synchronous)
6. the deferred message executes asynchronously, and outputs from the actual object, not grab

The grab object will not ever wait asynchronously for an output message.

-Joshua

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unexpected behaviour when grabbing jitter objects in scheduler thread

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