From: Craig Williams <craig@...80.com>
Date: 2009-03-16T07:29:33+09:00
Subject: Re: Keep thread in memory

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thanks Robert,

A simple loop..do will work and yes, a daemon is what I want to create. I'll
look it up and see if I can find some theory around this in Ruby. I should
have said a TSR right ;-)

Is it good practice in Ruby to sleep when in an infinite loop? or will Ruby
protect me from that kind of issue?

thanks,

-c


On Sun, Mar 15, 2009 at 6:22 PM, Robert Klemme
<shortcutter@googlemail.com>wrote:

> On 15.03.2009 22:35, Craig Williams wrote:
>
>> [Note:  parts of this message were removed to make it a legal post.]
>>
>> Hi,
>>
>> I'm writing a simple UDP listening server. It works great using this
>>
>> PORT = 1234
>> server = UDPSocket.open
>> server.bind("127.0.0.1", PORT)
>>
>> server_thread = Thread.start(server) do |server|
>>  100.times { #do something }
>> end
>>
>> server_thread.join
>>
>
> First of all, why are you using a thread here?  Do you have other work that
> needs to be done concurrently?
>
>  The above was based off some code from the Ruby 1.9 book - I have a
>> problem
>> now trying to take it a step further.
>>
>> How do I get the above to run permanently or until some other condition
>> besides (100) is reached?
>>
>
> Depends on the condition.  If you want this to run indefinitely you can
> simply do
>
> loop do
>  ...
> end
>
>  When I run this on my remote server over SSH it works but if I ctrl-z or
>> exit ssh, the process seems to be in memory but isn't actually working.
>> I'd
>> like to run it and have it go into memory until it is killed and return me
>> to the ssh command.
>>
>
> "Go into memory"???  All programs are executed in memory.  What you
> probably rather need is a demon, i.e. a program that continues to work even
> if the terminal gets removed (ssh close).
>
>  I tried leaving off the server_thread.join but then it just quits. Could
>> someone explain exactly what Thread.start is doing here.
>>
>
> In your example above the thread is completely superfluous since you do not
> do anything concurrently.  A plain old infinite loop would do the same job.
>  Basically your code is equivalent to
>
> PORT = 1234
> server = UDPSocket.open
> server.bind("127.0.0.1", PORT)
>
> 100.times { #do something }
>
> Kind regards
>
>        robert
>
>

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