🚀 go-pugleaf

On 2018-07-06, Gareth's Downstairs Computer
<headstone255.but.n...@yahoo.com> wrote:

> Do incompetent computer programmers become technical authors?

Nah, they go straight into management.

-- 
/~\  cgibbs@kltpzyxm.invalid (Charlie Gibbs)
\ /  I'm really at ac.dekanfrus if you read it the right way.
 X   Top-posted messages will probably be ignored.  See RFC1855.
/ \  Fight low-contrast text in web pages!  http://contrastrebellion.com

Charlie Gibbs <cgibbs@kltpzyxm.invalid> writes:

> On 2018-07-06, Gareth's Downstairs Computer
> <headstone255.but.n...@yahoo.com> wrote:
>
>> Do incompetent computer programmers become technical authors?
>
> Nah, they go straight into management.

Some do, some aren't so good at kissing up.

I'm not going to condemn every Tech Writer that way, but
that's one of many escape routes for failed computer
programmers.  Personally, I don't hold it against them.
If they can do an okay job at writing and were only
creating a mess at their attempts to code, more power to them.

I can't remember any Tech Writers that I thought were doing
a great job, but I was a pretty rare breed of programmer that
enjoyed doing my own documentation.  (And I think I did it well.)

I once re-did a tool with a streamlined procedure
and built in help.  I then attacked the inch thick documentation
and gave the tech writer the markup that changed the existing
one inch to about a quarter inch.  She refused to apply the
updates.

That led to an inevitable meeting.  One of the things she proposed
is reformatting so that the document contained a lot of white
space.  Fortunately, the ultimate outcome was that we stopped
using tech writers.

-- 
Dan Espen

In article <pho0pp$s4$1...@dont-email.me>,
Gareth's Downstairs Computer  <headstone255.but.n...@yahoo.com> wrote:
>Do incompetent computer programmers become technical authors?

Why do you ask?



-- 
Regards,
John Levine, jo...@iecc.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

On 06/07/2018 17:36, John Levine wrote:
> In article <pho0pp$s4$1...@dont-email.me>,
> Gareth's Downstairs Computer  <headstone255.but.n...@yahoo.com> wrote:
>> Do incompetent computer programmers become technical authors?
> 
> Why do you ask?
> 
> 
> 

To discover the answer.

Dan Espen <dan1...@gmail.com> writes:

> Charlie Gibbs <cgibbs@kltpzyxm.invalid> writes:
>
>> On 2018-07-06, Gareth's Downstairs Computer
>> <headstone255.but.n...@yahoo.com> wrote:
>>
>>> Do incompetent computer programmers become technical authors?
>>
>> Nah, they go straight into management.
>
> Some do, some aren't so good at kissing up.
>
> I'm not going to condemn every Tech Writer that way, but
> that's one of many escape routes for failed computer
> programmers.  Personally, I don't hold it against them.
> If they can do an okay job at writing and were only
> creating a mess at their attempts to code, more power to them.
>
> I can't remember any Tech Writers that I thought were doing
> a great job, but I was a pretty rare breed of programmer that
> enjoyed doing my own documentation.  (And I think I did it well.)

I actually knew a couple of students along the way who were hopelessly
incompetent programmers, but were able to either coordinate programmers
(so a future good manager) or document other people's code well.  One of
the latter went ahead and got a CS/English double major to be a tech
writer.

John Levine <jo...@taugh.com> wrote:
> In article <pho0pp$s4$1...@dont-email.me>,
> Gareth's Downstairs Computer  <headstone255.but.n...@yahoo.com> wrote:
>> Do incompetent computer programmers become technical authors?
> 
> Why do you ask?

Gareth has been unemployable for decades, btw. 

-- 
STC / M0TEY / 
http://twitter.com/ukradioamateur

On Fri, 06 Jul 2018 12:25:20 -0400
Dan Espen <dan1...@gmail.com> wrote:

> I can't remember any Tech Writers that I thought were doing
> a great job, but I was a pretty rare breed of programmer that
> enjoyed doing my own documentation.  (And I think I did it well.)

	I've only encountered one (I've mentioned her before here) but she
was never a programmer.

-- 
Steve O'Hara-Smith                          |   Directable Mirror Arrays
C:\>WIN                                     | A better way to focus the sun
The computer obeys and wins.                |    licences available see
You lose and Bill collects.                 |    http://www.sohara.org/

On 6 Jul 2018 15:50:16 GMT
Charlie Gibbs <cgibbs@kltpzyxm.invalid> wrote:

> On 2018-07-06, Gareth's Downstairs Computer
> <headstone255.but.n...@yahoo.com> wrote:
> 
> > Do incompetent computer programmers become technical authors?
> 
> Nah, they go straight into management.

	Yep, the sad thing is when it happens to competent programmers.

-- 
Steve O'Hara-Smith                          |   Directable Mirror Arrays
C:\>WIN                                     | A better way to focus the sun
The computer obeys and wins.                |    licences available see
You lose and Bill collects.                 |    http://www.sohara.org/

On 2018-07-06, Ahem A Rivet's Shot <ste...@eircom.net> wrote:

> On 6 Jul 2018 15:50:16 GMT
> Charlie Gibbs <cgibbs@kltpzyxm.invalid> wrote:
>
>> On 2018-07-06, Gareth's Downstairs Computer
>> <headstone255.but.n...@yahoo.com> wrote:
>> 
>>> Do incompetent computer programmers become technical authors?
>> 
>> Nah, they go straight into management.
>
> 	Yep, the sad thing is when it happens to competent programmers.

Which brings to mind that old Unix joke:

A programmer went into management and turned out to be quite good at it.
One of his old buddies, remembering how much fun he had as a programmer,
asked him whether he ever considered moving back.  "No," the manager
said.  "As you know, there is no return for a successful exec()."

-- 
/~\  cgibbs@kltpzyxm.invalid (Charlie Gibbs)
\ /  I'm really at ac.dekanfrus if you read it the right way.
 X   Top-posted messages will probably be ignored.  See RFC1855.
/ \  Fight low-contrast text in web pages!  http://contrastrebellion.com

On 7/6/2018 11:25 AM, Dan Espen wrote:
> Charlie Gibbs <cgibbs@kltpzyxm.invalid> writes:
> 
>> On 2018-07-06, Gareth's Downstairs Computer
>> <headstone255.but.n...@yahoo.com> wrote:
>>
>>> Do incompetent computer programmers become technical authors?
>>
>> Nah, they go straight into management.
> 
> Some do, some aren't so good at kissing up.
> 
> I'm not going to condemn every Tech Writer that way, but
> that's one of many escape routes for failed computer
> programmers.  Personally, I don't hold it against them.
> If they can do an okay job at writing and were only
> creating a mess at their attempts to code, more power to them.
> 

I thought this discussion was about writing books on computers and 
programming.  One tech writer who moved to writing computer and 
programming books... is Lance Leventhal.  He may do well as a tch 
writer, but I find his programming books to be poor!

One writer that I find producing excellent books on programming is a an 
named Tom Swan.  Unfortunately, Swan has moved on to other things, but 
might still be cajoled into writing a programming book again... if the 
right opportunity presents itself.

http://www.tomswan.com/


-- 
numerist at aquaporin4 dot com

On 7/6/2018 2:37 PM, Charlie Gibbs wrote:
> On 2018-07-06, Ahem A Rivet's Shot <ste...@eircom.net> wrote:
> 
>> On 6 Jul 2018 15:50:16 GMT
>> Charlie Gibbs <cgibbs@kltpzyxm.invalid> wrote:
>>
>>> On 2018-07-06, Gareth's Downstairs Computer
>>> <headstone255.but.n...@yahoo.com> wrote:
>>>
>>>> Do incompetent computer programmers become technical authors?
>>>
>>> Nah, they go straight into management.
>>
>> 	Yep, the sad thing is when it happens to competent programmers.
> 
> Which brings to mind that old Unix joke:
> 
> A programmer went into management and turned out to be quite good at it.
> One of his old buddies, remembering how much fun he had as a programmer,
> asked him whether he ever considered moving back.  "No," the manager
> said.  "As you know, there is no return for a successful exec()."
>
Can an unsuccessful exec() call return???  And where would it return to???


-- 
numerist at aquaporin4 dot com

Charles Richmond <nume...@aquaporin4.com> writes:

> On 7/6/2018 2:37 PM, Charlie Gibbs wrote:
>> On 2018-07-06, Ahem A Rivet's Shot <ste...@eircom.net> wrote:
>>
>>> On 6 Jul 2018 15:50:16 GMT
>>> Charlie Gibbs <cgibbs@kltpzyxm.invalid> wrote:
>>>
>>>> On 2018-07-06, Gareth's Downstairs Computer
>>>> <headstone255.but.n...@yahoo.com> wrote:
>>>>
>>>>> Do incompetent computer programmers become technical authors?
>>>>
>>>> Nah, they go straight into management.
>>>
>>> 	Yep, the sad thing is when it happens to competent programmers.
>>
>> Which brings to mind that old Unix joke:
>>
>> A programmer went into management and turned out to be quite good at it.
>> One of his old buddies, remembering how much fun he had as a programmer,
>> asked him whether he ever considered moving back.  "No," the manager
>> said.  "As you know, there is no return for a successful exec()."
>>
> Can an unsuccessful exec() call return???  And where would it return to???

The answer is in the man page:

RETURN VALUES
  If a function in the exec family returns to the calling process image,
  an error has occurred; the return value is -1 and errno is set to
  indicate the error.
  
-- 
Dan Espen

On 7/6/2018 8:00 PM, Dan Espen wrote:
> Charles Richmond <nume...@aquaporin4.com> writes:
> 
>> On 7/6/2018 2:37 PM, Charlie Gibbs wrote:
>>> On 2018-07-06, Ahem A Rivet's Shot <ste...@eircom.net> wrote:
>>>
>>>> On 6 Jul 2018 15:50:16 GMT
>>>> Charlie Gibbs <cgibbs@kltpzyxm.invalid> wrote:
>>>>
>>>>> On 2018-07-06, Gareth's Downstairs Computer
>>>>> <headstone255.but.n...@yahoo.com> wrote:
>>>>>
>>>>>> Do incompetent computer programmers become technical authors?
>>>>>
>>>>> Nah, they go straight into management.
>>>>
>>>> 	Yep, the sad thing is when it happens to competent programmers.
>>>
>>> Which brings to mind that old Unix joke:
>>>
>>> A programmer went into management and turned out to be quite good at it.
>>> One of his old buddies, remembering how much fun he had as a programmer,
>>> asked him whether he ever considered moving back.  "No," the manager
>>> said.  "As you know, there is no return for a successful exec()."
>>>
>> Can an unsuccessful exec() call return???  And where would it return to???
> 
> The answer is in the man page:
> 
> RETURN VALUES
>    If a function in the exec family returns to the calling process image,
>    an error has occurred; the return value is -1 and errno is set to
>    indicate the error.
>    

The calling process for exec() must be the child process.  ISTM the 
child process must signal the parent process and abort... if exec() fails.

-- 
numerist at aquaporin4 dot com

On Sat, 7 Jul 2018 00:05:12 -0500
Charles Richmond <nume...@aquaporin4.com> wrote:

> On 7/6/2018 8:00 PM, Dan Espen wrote:
> > Charles Richmond <nume...@aquaporin4.com> writes:
> > 
> >> On 7/6/2018 2:37 PM, Charlie Gibbs wrote:
> >>> On 2018-07-06, Ahem A Rivet's Shot <ste...@eircom.net> wrote:
> >>>
> >>>> On 6 Jul 2018 15:50:16 GMT
> >>>> Charlie Gibbs <cgibbs@kltpzyxm.invalid> wrote:
> >>>>
> >>>>> On 2018-07-06, Gareth's Downstairs Computer
> >>>>> <headstone255.but.n...@yahoo.com> wrote:
> >>>>>
> >>>>>> Do incompetent computer programmers become technical authors?
> >>>>>
> >>>>> Nah, they go straight into management.
> >>>>
> >>>> 	Yep, the sad thing is when it happens to competent
> >>>> programmers.
> >>>
> >>> Which brings to mind that old Unix joke:
> >>>
> >>> A programmer went into management and turned out to be quite good at
> >>> it. One of his old buddies, remembering how much fun he had as a
> >>> programmer, asked him whether he ever considered moving back.  "No,"
> >>> the manager said.  "As you know, there is no return for a successful
> >>> exec()."
> >>>
> >> Can an unsuccessful exec() call return???  And where would it return
> >> to???
> > 
> > The answer is in the man page:
> > 
> > RETURN VALUES
> >    If a function in the exec family returns to the calling process
> > image, an error has occurred; the return value is -1 and errno is set to
> >    indicate the error.
> >    
> 
> The calling process for exec() must be the child process.  ISTM the 
> child process must signal the parent process and abort... if exec() fails.

	There are no parent and child processes with exec(), it's all one
process. Calling exec() replaces the code in the *current* process with new
code, if it succeeds it cannot return because the return point no longer
exists. One obvious failure mode that leaves the original code intact is
being unable to read the file containing the new code in which case a
return is trivially possible and expected.

	If you want a child you have to fork().

-- 
Steve O'Hara-Smith                          |   Directable Mirror Arrays
C:\>WIN                                     | A better way to focus the sun
The computer obeys and wins.                |    licences available see
You lose and Bill collects.                 |    http://www.sohara.org/

On 7/7/2018 1:24 AM, Ahem A Rivet's Shot wrote:
> On Sat, 7 Jul 2018 00:05:12 -0500
> Charles Richmond <nume...@aquaporin4.com> wrote:
> 
>> On 7/6/2018 8:00 PM, Dan Espen wrote:
>>> Charles Richmond <nume...@aquaporin4.com> writes:
>>>
>>>> On 7/6/2018 2:37 PM, Charlie Gibbs wrote:
>>>>> On 2018-07-06, Ahem A Rivet's Shot <ste...@eircom.net> wrote:
>>>>>
>>>>>> On 6 Jul 2018 15:50:16 GMT
>>>>>> Charlie Gibbs <cgibbs@kltpzyxm.invalid> wrote:
>>>>>>
>>>>>>> On 2018-07-06, Gareth's Downstairs Computer
>>>>>>> <headstone255.but.n...@yahoo.com> wrote:
>>>>>>>
>>>>>>>> Do incompetent computer programmers become technical authors?
>>>>>>>
>>>>>>> Nah, they go straight into management.
>>>>>>
>>>>>> 	Yep, the sad thing is when it happens to competent
>>>>>> programmers.
>>>>>
>>>>> Which brings to mind that old Unix joke:
>>>>>
>>>>> A programmer went into management and turned out to be quite good at
>>>>> it. One of his old buddies, remembering how much fun he had as a
>>>>> programmer, asked him whether he ever considered moving back.  "No,"
>>>>> the manager said.  "As you know, there is no return for a successful
>>>>> exec()."
>>>>>
>>>> Can an unsuccessful exec() call return???  And where would it return
>>>> to???
>>>
>>> The answer is in the man page:
>>>
>>> RETURN VALUES
>>>     If a function in the exec family returns to the calling process
>>> image, an error has occurred; the return value is -1 and errno is set to
>>>     indicate the error.
>>>     
>>
>> The calling process for exec() must be the child process.  ISTM the
>> child process must signal the parent process and abort... if exec() fails.
> 
> 	There are no parent and child processes with exec(), it's all one
> process. Calling exec() replaces the code in the *current* process with new
> code, if it succeeds it cannot return because the return point no longer
> exists. One obvious failure mode that leaves the original code intact is
> being unable to read the file containing the new code in which case a
> return is trivially possible and expected.
> 
> 	If you want a child you have to fork().
> 

Yes, yes, of course...  the parent and child processes are the result of 
the fork() call.  From this pair of processes, the child will be the one 
to call exec() and over-write the executable with a new binary image. 
Therefore, if that exec fails, it will return to that child process.

Certainly the exec() call has *no* sense of child or parent, and needs 
none.  But when fork() creates the parent-child pair of processes, the 
child will be the one that will then call exec().

-- 
numerist at aquaporin4 dot com

On Sat, 7 Jul 2018 01:45:22 -0500
Charles Richmond <nume...@aquaporin4.com> wrote:

> Certainly the exec() call has *no* sense of child or parent, and needs 
> none.  But when fork() creates the parent-child pair of processes, the 
> child will be the one that will then call exec().

	Oh sure fork()/exec() is a common pattern but I've used
exec() without fork() and vice-versa a good many times - probably more
often than I've used them together.

-- 
Steve O'Hara-Smith                          |   Directable Mirror Arrays
C:\>WIN                                     | A better way to focus the sun
The computer obeys and wins.                |    licences available see
You lose and Bill collects.                 |    http://www.sohara.org/

On Sat, 07 Jul 2018 00:05:12 -0500, Charles Richmond wrote:

> On 7/6/2018 8:00 PM, Dan Espen wrote:
>> Charles Richmond <nume...@aquaporin4.com> writes:
>> 
>>> On 7/6/2018 2:37 PM, Charlie Gibbs wrote:
>>>> On 2018-07-06, Ahem A Rivet's Shot <ste...@eircom.net> wrote:
>>>>
>>>>> On 6 Jul 2018 15:50:16 GMT Charlie Gibbs <cgibbs@kltpzyxm.invalid>
>>>>> wrote:
>>>>>
>>>>>> On 2018-07-06, Gareth's Downstairs Computer
>>>>>> <headstone255.but.n...@yahoo.com> wrote:
>>>>>>
>>>>>>> Do incompetent computer programmers become technical authors?
>>>>>>
>>>>>> Nah, they go straight into management.
>>>>>
>>>>> 	Yep, the sad thing is when it happens to competent programmers.
>>>>
>>>> Which brings to mind that old Unix joke:
>>>>
>>>> A programmer went into management and turned out to be quite good at
>>>> it.
>>>> One of his old buddies, remembering how much fun he had as a
>>>> programmer,
>>>> asked him whether he ever considered moving back.  "No," the manager
>>>> said.  "As you know, there is no return for a successful exec()."
>>>>
>>> Can an unsuccessful exec() call return???  And where would it return
>>> to???
>> 
>> The answer is in the man page:
>> 
>> RETURN VALUES
>>    If a function in the exec family returns to the calling process
>>    image,
>>    an error has occurred; the return value is -1 and errno is set to
>>    indicate the error.
>>    
>>    
> The calling process for exec() must be the child process.  ISTM the
> child process must signal the parent process and abort... if exec()
> fails.

But note that an actual signal() is not required - the exit code should 
be enough to say that something has failed.



-- 
Using UNIX since v6 (1975)...

Use the BIG mirror service in the UK:
 http://www.mirrorservice.org

On 7/7/2018 2:17 AM, Ahem A Rivet's Shot wrote:
> On Sat, 7 Jul 2018 01:45:22 -0500
> Charles Richmond <nume...@aquaporin4.com> wrote:
> 
>> Certainly the exec() call has *no* sense of child or parent, and needs
>> none.  But when fork() creates the parent-child pair of processes, the
>> child will be the one that will then call exec().
> 
> 	Oh sure fork()/exec() is a common pattern but I've used
> exec() without fork() and vice-versa a good many times - probably more
> often than I've used them together.
> 

I can understand using exec() to chain several process images together. 
This can often be done with pipes, if the processes are built right... 
input from stdin, output to stdout.

-- 
numerist at aquaporin4 dot com

On 7 Jul 2018 08:55:20 GMT
Huge <Huge@nowhere.much.invalid> wrote:

> On 2018-07-07, Charles Richmond <nume...@aquaporin4.com> wrote:
> > On 7/6/2018 8:00 PM, Dan Espen wrote:
> 
> > The calling process for exec() must be the child process.  ISTM the 
> > child process must signal the parent process and abort... if exec()
> > fails.
> 
> Not necessarily. If the error is 'File not found', there *is* no child
> process.

	SOP exec() doesn't make children.

-- 
Steve O'Hara-Smith                          |   Directable Mirror Arrays
C:\>WIN                                     | A better way to focus the sun
The computer obeys and wins.                |    licences available see
You lose and Bill collects.                 |    http://www.sohara.org/

On Sat, 7 Jul 2018 05:42:40 -0500
Charles Richmond <nume...@aquaporin4.com> wrote:

> On 7/7/2018 2:17 AM, Ahem A Rivet's Shot wrote:
> > On Sat, 7 Jul 2018 01:45:22 -0500
> > Charles Richmond <nume...@aquaporin4.com> wrote:
> > 
> >> Certainly the exec() call has *no* sense of child or parent, and needs
> >> none.  But when fork() creates the parent-child pair of processes, the
> >> child will be the one that will then call exec().
> > 
> > 	Oh sure fork()/exec() is a common pattern but I've used
> > exec() without fork() and vice-versa a good many times - probably more
> > often than I've used them together.
> > 
> 
> I can understand using exec() to chain several process images together. 
> This can often be done with pipes, if the processes are built right... 
> input from stdin, output to stdout.

	Nope that needs several processes - think more in terms of a
dispatcher or overlay manager, It's been a longish time but some of the
CP/M application suites I wrote went from phase to phase using exec().

-- 
Steve O'Hara-Smith                          |   Directable Mirror Arrays
C:\>WIN                                     | A better way to focus the sun
The computer obeys and wins.                |    licences available see
You lose and Bill collects.                 |    http://www.sohara.org/

On Friday, July 6, 2018 at 8:10:49 AM UTC-7, Gareth's Downstairs Computer wrote: [...]

Competunt compooter progrunners Shrdlu beakum 

http://ai.neocities.org/maintainer.html 

AI Mind Maintainers. 

On 2018-07-07, Ahem A Rivet's Shot <ste...@eircom.net> wrote:
> On 7 Jul 2018 08:55:20 GMT
> Huge <Huge@nowhere.much.invalid> wrote:
>
>> On 2018-07-07, Charles Richmond <nume...@aquaporin4.com> wrote:
>> > On 7/6/2018 8:00 PM, Dan Espen wrote:
>> 
>> > The calling process for exec() must be the child process.  ISTM the 
>> > child process must signal the parent process and abort... if exec()
>> > fails.
>> 
>> Not necessarily. If the error is 'File not found', there *is* no child
>> process.
>
> 	SOP exec() doesn't make children.
>

Wot, no Weinstein :)


-- 
greymaus.ireland.ie
Will Rant for Food.

Charles Richmond <nume...@aquaporin4.com> writes:

> On 7/6/2018 8:00 PM, Dan Espen wrote:
>> Charles Richmond <nume...@aquaporin4.com> writes:
>>>>
>>> Can an unsuccessful exec() call return???  And where would it return to???
>>
>> The answer is in the man page:
>>
>> RETURN VALUES
>>    If a function in the exec family returns to the calling process image,
>>    an error has occurred; the return value is -1 and errno is set to
>>    indicate the error.
>>    
>
> The calling process for exec() must be the child process.  ISTM the
> child process must signal the parent process and abort... if exec()
> fails.

There is no requirement that there even be a child process.  There is no
reason a process can't replace its own running image using an exec().

If it's a normal fork&exec, the child process can just exit() (presumably
with an error return code) and the parent will find out about it in any
of the ways already available (including, of course, SIGCHLD).

In article <1bmuv2s...@pfeifferfamily.net> you write:
>> The calling process for exec() must be the child process.  ISTM the
>> child process must signal the parent process and abort... if exec()
>> fails.

No, both the child and parent process can do whatever they want.  It's
conventional for the child to exec() and the parent to wait(), but
that's just a convention, and nothing requires that.


>There is no requirement that there even be a child process.  There is no
>reason a process can't replace its own running image using an exec().

Actually, the *only* think exec() can do is to replace the running
process.  Sometimes there was a fork() shortly before, but that is
absoutely not required.  Think of the "exec" command in most shells
which says to run the command directly, no fork.


-- 
Regards,
John Levine, jo...@iecc.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

On 7/7/2018 6:16 PM, Joe Pfeiffer wrote:
> Charles Richmond <nume...@aquaporin4.com> writes:
> 
>> On 7/6/2018 8:00 PM, Dan Espen wrote:
>>> Charles Richmond <nume...@aquaporin4.com> writes:
>>>>>
>>>> Can an unsuccessful exec() call return???  And where would it return to???
>>>
>>> The answer is in the man page:
>>>
>>> RETURN VALUES
>>>     If a function in the exec family returns to the calling process image,
>>>     an error has occurred; the return value is -1 and errno is set to
>>>     indicate the error.
>>>     
>>
>> The calling process for exec() must be the child process.  ISTM the
>> child process must signal the parent process and abort... if exec()
>> fails.
> 
> There is no requirement that there even be a child process.  There is no
> reason a process can't replace its own running image using an exec().
> 

Yes, of course... isn't that what any process hopes to achieve by 
calling exec()???  I assume a process could even re-load its *own* image 
using exec().

> If it's a normal fork&exec, the child process can just exit() (presumably
> with an error return code) and the parent will find out about it in any
> of the ways already available (including, of course, SIGCHLD).
> 

But if tye parent process exits before killing the child... you could 
end up with a "zombie" process.  ISTM that SVR4 Unix had system calls 
that would allow the child to exit (and die) without parental approval...


-- 
numerist at aquaporin4 dot com

In article <phrnhi$ea6$1...@dont-email.me>,
Charles Richmond  <nume...@aquaporin4.com> wrote:
>But if tye parent process exits before killing the child... you could 
>end up with a "zombie" process.

No, that's completely backwards.  A zombie is a process that has
exited, but its parent hasn't waited for it yet.  It has just enough
context to return the pid and status to the parent.

When a process exits, all of its children, alive and zombie, are made
children of the init process #1.  It is always in a wait() loop so
it'll reap the zombies and ignore them.

-- 
Regards,
John Levine, jo...@iecc.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

Charles Richmond <nume...@aquaporin4.com> writes:

> On 7/7/2018 6:16 PM, Joe Pfeiffer wrote:
>> Charles Richmond <nume...@aquaporin4.com> writes:
>>
>>> On 7/6/2018 8:00 PM, Dan Espen wrote:
>>>> Charles Richmond <nume...@aquaporin4.com> writes:
>>>>>>
>>>>> Can an unsuccessful exec() call return???  And where would it return to???
>>>>
>>>> The answer is in the man page:
>>>>
>>>> RETURN VALUES
>>>>     If a function in the exec family returns to the calling process image,
>>>>     an error has occurred; the return value is -1 and errno is set to
>>>>     indicate the error.
>>>>     
>>>
>>> The calling process for exec() must be the child process.  ISTM the
>>> child process must signal the parent process and abort... if exec()
>>> fails.
>>
>> There is no requirement that there even be a child process.  There is no
>> reason a process can't replace its own running image using an exec().
>>
>
> Yes, of course... isn't that what any process hopes to achieve by
> calling exec()???  I assume a process could even re-load its *own*
> image using exec().

You're the one who said the child has to call exec(); I was pointing out
that there's no requirement that there even *be* a child.

>> If it's a normal fork&exec, the child process can just exit() (presumably
>> with an error return code) and the parent will find out about it in any
>> of the ways already available (including, of course, SIGCHLD).
>>
>
> But if tye parent process exits before killing the child... you could
> end up with a "zombie" process.  ISTM that SVR4 Unix had system calls
> that would allow the child to exit (and die) without parental
> approval...

You're talking about an orphan.  A process is a zombie when it has
terminated and its parent has not yet reaped it.  An orphan process is
reparented; init becomes its parent.  I can't think off hand of a call
that would assign a child to some other parent than that.

On 7/7/2018 8:16 PM, Joe Pfeiffer wrote:
> Charles Richmond <nume...@aquaporin4.com> writes:
> 
>> On 7/7/2018 6:16 PM, Joe Pfeiffer wrote:
>>> Charles Richmond <nume...@aquaporin4.com> writes:
>>>
>>>> On 7/6/2018 8:00 PM, Dan Espen wrote:
>>>>> Charles Richmond <nume...@aquaporin4.com> writes:
>>>>>>>
>>>>>> Can an unsuccessful exec() call return???  And where would it return to???
>>>>>
>>>>> The answer is in the man page:
>>>>>
>>>>> RETURN VALUES
>>>>>      If a function in the exec family returns to the calling process image,
>>>>>      an error has occurred; the return value is -1 and errno is set to
>>>>>      indicate the error.
>>>>>      
>>>>
>>>> The calling process for exec() must be the child process.  ISTM the
>>>> child process must signal the parent process and abort... if exec()
>>>> fails.
>>>
>>> There is no requirement that there even be a child process.  There is no
>>> reason a process can't replace its own running image using an exec().
>>>
>>
>> Yes, of course... isn't that what any process hopes to achieve by
>> calling exec()???  I assume a process could even re-load its *own*
>> image using exec().
> 
> You're the one who said the child has to call exec(); I was pointing out
> that there's no requirement that there even *be* a child.
> 
>>> If it's a normal fork&exec, the child process can just exit() (presumably
>>> with an error return code) and the parent will find out about it in any
>>> of the ways already available (including, of course, SIGCHLD).
>>>
>>
>> But if tye parent process exits before killing the child... you could
>> end up with a "zombie" process.  ISTM that SVR4 Unix had system calls
>> that would allow the child to exit (and die) without parental
>> approval...
> 
> You're talking about an orphan.  A process is a zombie when it has
> terminated and its parent has not yet reaped it.  An orphan process is
> reparented; init becomes its parent.  I can't think off hand of a call
> that would assign a child to some other parent than that.
> 
> 

In the first edition of _Advanced Programming in the UNIX Environment-, 
by W. Richard Stevens (RIP)...   pages 280-281:

"If a process specifically sets its disposition to SIG_IGN, children of 
the calling process will *not* generate zombie processes. ...  Instead, 
on termination, the status of these child processes is just discarded."

In the above case, the parent does *not* have to "reap" the child process.

-- 
numerist at aquaporin4 dot com