Asp Forum - win32/process question

Joe Van Dyk

11/10/2006 5:39:00 AM

On Windows XP, Ruby 1.8.5:

# start notepad
irb(main):003:0> info = Process.create :app_name => "notepad"
=> #<struct Struct::ProcessInfo process_handle=1916,
thread_handle=1912, process_id=3536, thread_id=3088>

# notepad running
irb(main):004:0> Process.kill 0, info.process_id
=> [3536]

# kill notepad
irb(main):005:0> Process.kill 9, info.process_id
=> [3536]

# notepad's dead, but why doesn't this throw an exception?!
irb(main):006:0> Process.kill 0, info.process_id
=> [3536]

Any ideas?
Thanks,
Joe

9 Answers

Joe Van Dyk

11/10/2006 6:24:00 AM

I guess I should note that this is after I require 'win32/process'
(which is installed via a gem).

On 11/9/06, J-Van <joevandyk@gmail.com> wrote:
> On Windows XP, Ruby 1.8.5:
>
> # start notepad
> irb(main):003:0> info = Process.create :app_name => "notepad"
> => #<struct Struct::ProcessInfo process_handle=1916,
> thread_handle=1912, process_id=3536, thread_id=3088>
>
> # notepad running
> irb(main):004:0> Process.kill 0, info.process_id
> => [3536]
>
> # kill notepad
> irb(main):005:0> Process.kill 9, info.process_id
> => [3536]
>
> # notepad's dead, but why doesn't this throw an exception?!
> irb(main):006:0> Process.kill 0, info.process_id
> => [3536]
>
> Any ideas?
> Thanks,
> Joe
>

Park Heesob

11/10/2006 10:28:00 AM

Hi,

>From: J-Van <joevandyk@gmail.com>
>Reply-To: ruby-talk@ruby-lang.org
>To: ruby-talk@ruby-lang.org (ruby-talk ML)
>Subject: Re: win32/process question
>Date: Fri, 10 Nov 2006 15:23:58 +0900
>
>I guess I should note that this is after I require 'win32/process'
>(which is installed via a gem).
>
>On 11/9/06, J-Van <joevandyk@gmail.com> wrote:
>>On Windows XP, Ruby 1.8.5:
>>
>># start notepad
>>irb(main):003:0> info = Process.create :app_name => "notepad"
>>=> #<struct Struct::ProcessInfo process_handle=1916,
>>thread_handle=1912, process_id=3536, thread_id=3088>
>>
>># notepad running
>>irb(main):004:0> Process.kill 0, info.process_id
>>=> [3536]
>>
>># kill notepad
>>irb(main):005:0> Process.kill 9, info.process_id
>>=> [3536]
>>
>># notepad's dead, but why doesn't this throw an exception?!
>>irb(main):006:0> Process.kill 0, info.process_id
>>=> [3536]
>>
>>Any ideas?
>>Thanks,
>>Joe
>>
>
Refer to http://msdn2.microsoft.com/fr-fr/library/ms6...,
"While open handles to kernel objets are closed automatically when a process
terminates, the objects themselves exist until all open handles to them are
closed. Therefore, an object will remain valid after a process that is using
it terminates if another process has an open handle to it."

Here is the working code.

irb(main):001:0> require 'win32/process'
=> true
irb(main):002:0> include Windows::Handle
=> Object
irb(main):003:0> info = Process.create :app_name=>'notepad'
=> #<struct Struct::ProcessInfo process_handle=1916, thread_handle=1912,
process
_id=1748, thread_id=1108>
irb(main):004:0> Process.kill 0,info.process_id
=> [1748]
irb(main):005:0> Process.kill 9,info.process_id
=> [1748]
irb(main):006:0> CloseHandle(info.process_handle)
=> true
irb(main):007:0> CloseHandle(info.thread_handle)
=> true
irb(main):008:0> Process.kill 0,info.process_id
ProcessError: The parameter is incorrect.
from
c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
s.rb:156:in `kill'
from
c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
s.rb:132:in `each'
from
c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
s.rb:132:in `kill'
from (irb):8

Regards,

Park Heesob

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Joe Van Dyk

11/10/2006 6:23:00 PM

On 11/10/06, Park Heesob <phasis68@hotmail.com> wrote:
>
> Hi,
>
> >From: J-Van <joevandyk@gmail.com>
> >Reply-To: ruby-talk@ruby-lang.org
> >To: ruby-talk@ruby-lang.org (ruby-talk ML)
> >Subject: Re: win32/process question
> >Date: Fri, 10 Nov 2006 15:23:58 +0900
> >
> >I guess I should note that this is after I require 'win32/process'
> >(which is installed via a gem).
> >
> >On 11/9/06, J-Van <joevandyk@gmail.com> wrote:
> >>On Windows XP, Ruby 1.8.5:
> >>
> >># start notepad
> >>irb(main):003:0> info = Process.create :app_name => "notepad"
> >>=> #<struct Struct::ProcessInfo process_handle=1916,
> >>thread_handle=1912, process_id=3536, thread_id=3088>
> >>
> >># notepad running
> >>irb(main):004:0> Process.kill 0, info.process_id
> >>=> [3536]
> >>
> >># kill notepad
> >>irb(main):005:0> Process.kill 9, info.process_id
> >>=> [3536]
> >>
> >># notepad's dead, but why doesn't this throw an exception?!
> >>irb(main):006:0> Process.kill 0, info.process_id
> >>=> [3536]
> >>
> >>Any ideas?
> >>Thanks,
> >>Joe
> >>
> >
> Refer to http://msdn2.microsoft.com/fr-fr/library/ms6...,
> "While open handles to kernel objets are closed automatically when a process
> terminates, the objects themselves exist until all open handles to them are
> closed. Therefore, an object will remain valid after a process that is using
> it terminates if another process has an open handle to it."
>
> Here is the working code.
>
> irb(main):001:0> require 'win32/process'
> => true
> irb(main):002:0> include Windows::Handle
> => Object
> irb(main):003:0> info = Process.create :app_name=>'notepad'
> => #<struct Struct::ProcessInfo process_handle=1916, thread_handle=1912,
> process
> _id=1748, thread_id=1108>
> irb(main):004:0> Process.kill 0,info.process_id
> => [1748]
> irb(main):005:0> Process.kill 9,info.process_id
> => [1748]
> irb(main):006:0> CloseHandle(info.process_handle)
> => true
> irb(main):007:0> CloseHandle(info.thread_handle)
> => true
> irb(main):008:0> Process.kill 0,info.process_id
> ProcessError: The parameter is incorrect.
> from
> c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
> s.rb:156:in `kill'
> from
> c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
> s.rb:132:in `each'
> from
> c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
> s.rb:132:in `kill'
> from (irb):8

Fantastic, thanks!

Joe

Joe Van Dyk

11/10/2006 6:25:00 PM

Park Heesob

11/11/2006 12:19:00 AM

Hi,

>From: J-Van <joevandyk@gmail.com>
>Reply-To: ruby-talk@ruby-lang.org
>To: ruby-talk@ruby-lang.org (ruby-talk ML)
>Subject: Re: win32/process question
>Date: Sat, 11 Nov 2006 03:24:34 +0900
>
>On 11/10/06, Park Heesob <phasis68@hotmail.com> wrote:
>>
>>Hi,
>>
....
>> >
>>Refer to http://msdn2.microsoft.com/fr-fr/library/ms6...,
>>"While open handles to kernel objets are closed automatically when a
>>process
>>terminates, the objects themselves exist until all open handles to them
>>are
>>closed. Therefore, an object will remain valid after a process that is
>>using
>>it terminates if another process has an open handle to it."
>>
>>Here is the working code.
>>
>>irb(main):001:0> require 'win32/process'
>>=> true
>>irb(main):002:0> include Windows::Handle
>>=> Object
>>irb(main):003:0> info = Process.create :app_name=>'notepad'
>>=> #<struct Struct::ProcessInfo process_handle=1916, thread_handle=1912,
>>process
>>_id=1748, thread_id=1108>
>>irb(main):004:0> Process.kill 0,info.process_id
>>=> [1748]
>>irb(main):005:0> Process.kill 9,info.process_id
>>=> [1748]
>>irb(main):006:0> CloseHandle(info.process_handle)
>>=> true
>>irb(main):007:0> CloseHandle(info.thread_handle)
>>=> true
>>irb(main):008:0> Process.kill 0,info.process_id
>>ProcessError: The parameter is incorrect.
>> from
>>c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
>>s.rb:156:in `kill'
>> from
>>c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
>>s.rb:132:in `each'
>> from
>>c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
>>s.rb:132:in `kill'
>> from (irb):8
>
>So, if I use Process.create to create a new process, and I want to
>know when a user closed the program, I should close the handle to the
>process immediately after starting it? And then Process.kill(0,
><pid>) would return an exception once the user closed the program?
>
>Joe
>
You cannot close the hanle if the process is still alive. You can use
WaitForSingleObject or Process.waitpid to wait until child process exits
like this:

require 'win32/process'
include Windows::Handle
info = Process.create :app_name=>'notepad'
Process.waitpid(info.process_id)
CloseHandle(info.process_handle)
CloseHandle(info.thread_handle)

Regards,

Park Heesob

_________________________________________________________________
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Joe Van Dyk

11/11/2006 12:29:00 AM

On 11/10/06, Park Heesob <phasis68@hotmail.com> wrote:
>
> Hi,
>
> >From: J-Van <joevandyk@gmail.com>
> >Reply-To: ruby-talk@ruby-lang.org
> >To: ruby-talk@ruby-lang.org (ruby-talk ML)
> >Subject: Re: win32/process question
> >Date: Sat, 11 Nov 2006 03:24:34 +0900
> >
> >On 11/10/06, Park Heesob <phasis68@hotmail.com> wrote:
> >>
> >>Hi,
> >>
> ....
> >> >
> >>Refer to http://msdn2.microsoft.com/fr-fr/library/ms6...,
> >>"While open handles to kernel objets are closed automatically when a
> >>process
> >>terminates, the objects themselves exist until all open handles to them
> >>are
> >>closed. Therefore, an object will remain valid after a process that is
> >>using
> >>it terminates if another process has an open handle to it."
> >>
> >>Here is the working code.
> >>
> >>irb(main):001:0> require 'win32/process'
> >>=> true
> >>irb(main):002:0> include Windows::Handle
> >>=> Object
> >>irb(main):003:0> info = Process.create :app_name=>'notepad'
> >>=> #<struct Struct::ProcessInfo process_handle=1916, thread_handle=1912,
> >>process
> >>_id=1748, thread_id=1108>
> >>irb(main):004:0> Process.kill 0,info.process_id
> >>=> [1748]
> >>irb(main):005:0> Process.kill 9,info.process_id
> >>=> [1748]
> >>irb(main):006:0> CloseHandle(info.process_handle)
> >>=> true
> >>irb(main):007:0> CloseHandle(info.thread_handle)
> >>=> true
> >>irb(main):008:0> Process.kill 0,info.process_id
> >>ProcessError: The parameter is incorrect.
> >> from
> >>c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
> >>s.rb:156:in `kill'
> >> from
> >>c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
> >>s.rb:132:in `each'
> >> from
> >>c:/ruby/lib/ruby/gems/1.8/gems/win32-process-0.5.1/lib/win32/proces
> >>s.rb:132:in `kill'
> >> from (irb):8
> >
> >So, if I use Process.create to create a new process, and I want to
> >know when a user closed the program, I should close the handle to the
> >process immediately after starting it? And then Process.kill(0,
> ><pid>) would return an exception once the user closed the program?
> >
> >Joe
> >
> You cannot close the hanle if the process is still alive. You can use
> WaitForSingleObject or Process.waitpid to wait until child process exits
> like this:
>
> require 'win32/process'
> include Windows::Handle
> info = Process.create :app_name=>'notepad'
> Process.waitpid(info.process_id)
> CloseHandle(info.process_handle)
> CloseHandle(info.thread_handle)

If I use Process.waitpid in a thread, all the other threads seem to
block until the process that I'm waiting for stops.

I'm writing a program that runs on a windows machine that listens for
requests to start and kill programs. It needs to be able to run and
kill multiple programs and needs to be able to monitor the programs
that it has started to make sure that they are still running. If
Process.waitpid makes the whole Ruby process hang, that's no good.

Joe

Park Heesob

11/11/2006 1:07:00 AM

>From: J-Van <joevandyk@gmail.com>
>Reply-To: ruby-talk@ruby-lang.org
>To: ruby-talk@ruby-lang.org (ruby-talk ML)
>Subject: Re: win32/process question
>Date: Sat, 11 Nov 2006 09:29:10 +0900
>
....
>
>If I use Process.waitpid in a thread, all the other threads seem to
>block until the process that I'm waiting for stops.
>
>I'm writing a program that runs on a windows machine that listens for
>requests to start and kill programs. It needs to be able to run and
>kill multiple programs and needs to be able to monitor the programs
>that it has started to make sure that they are still running. If
>Process.waitpid makes the whole Ruby process hang, that's no good.
>
>Joe
>
If you don't want blocking, try WaitForSingleObect like this:

require 'win32/process'
include Windows::Handle
include Windows::Synchronize

info = Process.create :app_name=>'notepad'

begin
i = WaitForSingleObject(info.process_handle,10)
if i==WAIT_OBJECT_0
CloseHandle(info.process_handle)
CloseHandle(info.thread_handle)
end

# do something

end while i==WAIT_TIMEOUT

Regards,

Park Heesob

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Joe Van Dyk

11/11/2006 1:28:00 AM

On 11/10/06, Park Heesob <phasis68@hotmail.com> wrote:
> >From: J-Van <joevandyk@gmail.com>
> >Reply-To: ruby-talk@ruby-lang.org
> >To: ruby-talk@ruby-lang.org (ruby-talk ML)
> >Subject: Re: win32/process question
> >Date: Sat, 11 Nov 2006 09:29:10 +0900
> >
> ....
> >
> >If I use Process.waitpid in a thread, all the other threads seem to
> >block until the process that I'm waiting for stops.
> >
> >I'm writing a program that runs on a windows machine that listens for
> >requests to start and kill programs. It needs to be able to run and
> >kill multiple programs and needs to be able to monitor the programs
> >that it has started to make sure that they are still running. If
> >Process.waitpid makes the whole Ruby process hang, that's no good.
> >
> >Joe
> >
> If you don't want blocking, try WaitForSingleObect like this:
>
> require 'win32/process'
> include Windows::Handle
> include Windows::Synchronize
>
> info = Process.create :app_name=>'notepad'
>
> begin
> i = WaitForSingleObject(info.process_handle,10)
> if i==WAIT_OBJECT_0
> CloseHandle(info.process_handle)
> CloseHandle(info.thread_handle)
> end
>
> # do something
>
> end while i==WAIT_TIMEOUT

Thanks -- I'll try that. I'm not exactly sure what those functions do
though. :-)

Joe

Daniel Berger

11/21/2006 7:06:00 PM

Park Heesob wrote:

<snip>

> >So, if I use Process.create to create a new process, and I want to
> >know when a user closed the program, I should close the handle to the
> >process immediately after starting it? And then Process.kill(0,
> ><pid>) would return an exception once the user closed the program?
> >
> >Joe
> >
> You cannot close the hanle if the process is still alive. You can use
> WaitForSingleObject or Process.waitpid to wait until child process exits
> like this:
>
> require 'win32/process'
> include Windows::Handle
> info = Process.create :app_name=>'notepad'
> Process.waitpid(info.process_id)
> CloseHandle(info.process_handle)
> CloseHandle(info.thread_handle)

Hm, maybe we should provide a block form for Process.create that does
this behind the scenes. What do you think?

Regards,

Dan

comp.lang.ruby

win32/process question

Joe Van Dyk

Joe Van Dyk

Park Heesob

Joe Van Dyk

Joe Van Dyk

Park Heesob

Joe Van Dyk

Park Heesob

Joe Van Dyk

Daniel Berger

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