Re: misterious behavior of either kill or terminal

From	owl <owl@rooftop.invalid>
Newsgroups	alt.os.linux
Subject	Re: misterious behavior of either kill or terminal
Date	2019-06-28 14:51 +0000
Organization	O.W.L.
Message-ID	<suzv9983ta.gayu4@rooftop.invalid> (permalink)
References	(3 earlier) <171huf-87h.ln1@Telcontar.valinor> <qf4n03$8cd$1@gioia.aioe.org> <7g4huf-cfj.ln1@Telcontar.valinor> <87mui16gm6.fsf@LkoBDZeT.terraraq.uk> <l3fhuf-ltq.ln1@Telcontar.valinor>

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Carlos E.R. <robin_listas@es.invalid> wrote:
> On 28/06/2019 14.26, Richard Kettlewell wrote:
>> "Carlos E.R." <robin_listas@es.invalid> writes:
>>> On 28/06/2019 11.35, Georges wrote:
>>>> Le 28/06/2019 à 10:54, Carlos E.R. a écrit :
>>>>> Why should a process die if sent a signal that it doesn't handle?
>>>>> SIGUSR1,2 are defined by the application. What they mean is entirely up
>>>>> to the application, there is no default action.
>>>>>
>>>>
>>>> Hi Carlos, if no handler found, the SIGUSR1 and SIGUSR2 default action
>>>> is 'term'(inate) the process.
>>>>
>>>> http://man7.org/linux/man-pages/man7/signal.7.html
>>>
>>> I looked at the manual before writing. I still do not see it. What it
>>> says is:
>>>
>>>        SIGUSR1      P1990      Term    User-defined signal 1
>>>        SIGUSR2      P1990      Term    User-defined signal 2
>>                                  ^^^^
>> Here -----------------------------/
> 
> What's that? A Terminal related signal? Doesn't say anything to me.
> Terminate? Then write "terminate". Nor the p1990. Page, year?  My man
> page says value ant it is "30,10,16" and  "31,12,17", not "p1990".
> 

Both "Term" and "P1990" are defined at the above link.


>> 
>>> That's it. However, there is another paragraph I see when searching for
>>> "default":
>>>
>>>        Unlike standard signals, real-time signals have no predefined
>>>        meanings: the entire set of real-time signals can be used for
>>>        application-defined purposes.
>>>
>>>        The default action for an unhandled real-time signal is to
>>>        terminate the receiving process.
>> 
>> Irrelevant, SIGUSR1 is not a real-time signal.
> 
> Then it doesn't say the default action is terminate, the default action
> is something else.
> 

It does say that in the table.


>>> But my question remains: why should the default action be terminate the
>>> program, and not ignore? I find this absurd. What is the logic in
>>> terminating the program on ANY unknown signal?
>> 
>> You could as easily ask what the point of ignoring any unknown signal
>> would be.
> 
> Why? I see it obvious that if my program doesn't want to respond to a
> signal, I simply don't program anything for it. No handler, no default
> action, nothing done.
> 
> It is a user defined signal, it is up to me to do something or ignore
> it. Should be.
> 
> To kill a program there are specific signals.
> 

POSIX specifies the default action.

Thread

misterious behavior of either kill or terminal Soviet_Mario <SovietMario@CCCP.MIR> - 2019-06-21 20:07 +0200
  Re: misterious behavior of either kill or terminal Dan Purgert <dan@djph.net> - 2019-06-21 18:21 +0000
    Re: misterious behavior of either kill or terminal marrgol <marrgol@address.invalid> - 2019-06-22 13:27 +0200
    Re: misterious behavior of either kill or terminal Jasen Betts <jasen@xnet.co.nz> - 2019-06-23 05:31 +0000
      Re: misterious behavior of either kill or terminal "Carlos E.R." <robin_listas@es.invalid> - 2019-06-28 10:54 +0200
        Funny... (Was: misterious behavior of either kill or terminal) gazelle@shell.xmission.com (Kenny McCormack) - 2019-06-28 09:15 +0000
        Re: misterious behavior of either kill or terminal Georges <georges@prout.com> - 2019-06-28 11:35 +0200
          Re: misterious behavior of either kill or terminal "Carlos E.R." <robin_listas@es.invalid> - 2019-06-28 11:50 +0200
            Re: misterious behavior of either kill or terminal Georges <georges@prout.com> - 2019-06-28 12:21 +0200
            Re: misterious behavior of either kill or terminal Richard Kettlewell <invalid@invalid.invalid> - 2019-06-28 13:26 +0100
              Re: misterious behavior of either kill or terminal "Carlos E.R." <robin_listas@es.invalid> - 2019-06-28 14:51 +0200
                Re: misterious behavior of either kill or terminal Richard Kettlewell <invalid@invalid.invalid> - 2019-06-28 14:10 +0100
                Re: misterious behavior of either kill or terminal "Carlos E.R." <robin_listas@es.invalid> - 2019-06-28 20:06 +0200
                Re: misterious behavior of either kill or terminal Georges <georges@prout.com> - 2019-06-28 20:54 +0200
                Re: misterious behavior of either kill or terminal owl <owl@rooftop.invalid> - 2019-06-28 14:51 +0000
                Re: misterious behavior of either kill or terminal "F. Russell" <frussell@random.info> - 2019-06-28 17:40 +0000
              Re: misterious behavior of either kill or terminal Soviet_Mario <SovietMario@CCCP.MIR> - 2019-06-28 16:45 +0200
        Re: misterious behavior of either kill or terminal Jasen Betts <jasen@xnet.co.nz> - 2019-06-28 10:29 +0000
          Re: misterious behavior of either kill or terminal "Carlos E.R." <robin_listas@es.invalid> - 2019-06-28 14:54 +0200
  Re: misterious behavior of either kill or terminal "Carlos E.R." <robin_listas@es.invalid> - 2019-06-21 20:26 +0200
    Re: misterious behavior of either kill or terminal Soviet_Mario <SovietMario@CCCP.MIR> - 2019-06-22 00:02 +0200
      Re: misterious behavior of either kill or terminal "Carlos E.R." <robin_listas@es.invalid> - 2019-06-22 13:17 +0200
        Re: misterious behavior of either kill or terminal marrgol <marrgol@address.invalid> - 2019-06-22 13:32 +0200
          Re: misterious behavior of either kill or terminal Soviet_Mario <SovietMario@CCCP.MIR> - 2019-06-23 17:57 +0200
  Re: misterious behavior of either kill or terminal Paul <nospam@needed.invalid> - 2019-06-21 15:14 -0400
    Re: misterious behavior of either kill or terminal Melzzzzz <Melzzzzz@zzzzz.com> - 2019-06-21 20:42 +0000
    Re: misterious behavior of either kill or terminal Soviet_Mario <SovietMario@CCCP.MIR> - 2019-06-22 00:23 +0200
      Re: misterious behavior of either kill or terminal "J.O. Aho" <user@example.net> - 2019-06-22 09:50 +0200
        Re: misterious behavior of either kill or terminal gazelle@shell.xmission.com (Kenny McCormack) - 2019-06-22 19:13 +0000
          Re: misterious behavior of either kill or terminal "J.O. Aho" <user@example.net> - 2019-06-22 23:41 +0200
      Re: misterious behavior of either kill or terminal "Carlos E.R." <robin_listas@es.invalid> - 2019-06-22 13:30 +0200
  Re: misterious behavior of either kill or terminal "J.O. Aho" <user@example.net> - 2019-06-21 21:39 +0200
    Re: misterious behavior of either kill or terminal Soviet_Mario <SovietMario@CCCP.MIR> - 2019-06-22 00:33 +0200
      Re: misterious behavior of either kill or terminal "J.O. Aho" <user@example.net> - 2019-06-22 09:28 +0200
      Re: misterious behavior of either kill or terminal "Carlos E.R." <robin_listas@es.invalid> - 2019-06-22 13:34 +0200

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