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Re: [Help-smalltalk] Delay in a Process and sending #terminate
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From: |
Paolo Bonzini |
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Subject: |
Re: [Help-smalltalk] Delay in a Process and sending #terminate |
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Date: |
Sat, 18 Dec 2010 13:35:06 +0100 |
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User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.12) Gecko/20101103 Fedora/1.0-0.33.b2pre.fc14 Lightning/1.0b3pre Mnenhy/0.8.3 Thunderbird/3.1.6 |
On 12/18/2010 11:38 AM, Holger Hans Peter Freyther wrote:
$ a := [[(Delay forSeconds: 300) wait] ensure: ['Terminated' printNl]] fork.
$ a terminate
Process(nil at userSchedulingPriority, ready to run)
$ a terminate
'Terminated'
Process(nil at userSchedulingPriority, terminated)
Not a bug, it won't happen when you run the program outside the REPL (or
if the REPL let processes run in the background.
To work around such sticky processes I have decided to use a [proc
isTerminated] whileFalse: [proc terminate] construct.
It's enough to do
proc terminate. [proc isTerminated] whileFalse: [Processor yield]
For example:
st> Eval [
proc := [[(Delay forSeconds: 300) wait]
ensure: ['Terminated' printNl]] fork.
proc terminate.
[proc isTerminated] whileFalse: [Processor yield].
proc
]
'Terminated'
Process(nil at userSchedulingPriority, terminated)
The reason is that termination is a non-trivial operation which involves
sending the ProcessBeingTerminated exception. It also may cause a
context switch.
Paolo