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Re: singleton for script with shebang


From: Bradley Asztalos
Subject: Re: singleton for script with shebang
Date: Sun, 4 Jan 2015 10:26:50 -0800

Ole,

RobberA is robbing a bank and posts her accomplice, RobberB, outside the door to keep watch. Independently, RobberC arrives on the scene to rob the bank as well, noticing that the bank is <<being>> robbed, she takes off and vows to give up her life of crime.

Compare: RobberA&B finish their hard days work and leave, when RobberC arrives, .2s later, to Rob a bank that has no money, three dead clerks, a screaming child and cops on their way. RobberC gets hanged for murder.

Compare: RobberA&B finish their hard days work and leave, when RobberC arrives, 1s later, and notices the bank security guard coming out the door in pursuit of RobberA&B. RobberC robs a different bank.

The case I was differentiating was between 0 && !0 where actionable information is held by the mutex or semaphore itself, and no other variables are required. Obviously in the difference between .2 and 1 is not contained within the semaphore but in some other time variable. 

With that said, I have no intention of robbing a bank, at least in the foreseeable future, and the question from my side at least was pure pedantry. I withdraw the question ;)

Thanks again for your great work, and--just as importantly--careful oversight of this forum. 

Bradley

On Sun, Jan 4, 2015 at 6:26 AM, Ole Tange <ole@tange.dk> wrote:
On Sat, Jan 3, 2015 at 10:09 PM, Bradley <brad@customweather.com> wrote:
>> On Jan 3, 27 Heisei, at 11:21 AM, Ole Tange <ole@tange.dk> wrote:
>>> On Fri, Jan 2, 2015 at 8:53 PM, Bradley Asztalos <brad@customweather.com> wrote:
>>>> On Fri, Jan 2, 2015 at 7:35 AM, Ole Tange <ole@tange.dk> wrote:
>>>> On Fri, Jan 2, 2015 at 10:51 AM, Bradley Asztalos
>>>> <brad@customweather.com> wrote:
:
>>> Does --semaphoretimeout 0 mean never give up?
>>
>> Yes: Just as if the option had not been given.
>>
>>> If so then -0 could mean give up immediately.
>>
>> -0 = 0, so no.
>>
>> It is implemented in the git version.
:
> So did you provide for a way to give up immediately if sem cannot be acquired immediately?

As mentioned, no.

If you feel that is very important, please provide a situation where
waiting 1 sec for the semaphore before giving up is much worse than
waiting 0.2 sec (which is more or less the time it takes to run sem).
I could not find a situation in which that extra second made a huge
difference. On the contrary I can easily find situations where giving
up immediately is less useful than trying for just a second.

/Ole


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