subprocess: reading from stdout hangs process termination, waiting for ENTER keyboard signal
Hello everyone.
I'm trying to use subprocess module to launch a Windows console
application. The application prints some results to standard output
and then waits for the user to press any key to terminte. I can't
control this behaviour, as the application is not mine...
I'm stuck at the very first lines of my code. I'm trying to force
process termination (even with proc.terminate()), and it works only if
I don't read from stdout. If I do proc.stdout.read() the process
hangs, and I have to manually press the keyboard to interrupt it.
Probably it's due a low-level handle that is kept on the process
stdout, waiting for the keypress event...
How can I solve it?
Giovanni
--- Code excerpt---
proc = subprocess.Popen('the_app.exe',
shell=True,
stdout=subprocess.PIPE,
)
#stdout_value = proc.communicate()[0]
stdout_value = proc.stdout.read()
PROCESS_TERMINATE = 1
handle = win32api.OpenProcess(PROCESS_TERMINATE, False, proc.pid)
win32api.TerminateProcess(handle, -1)
win32api.CloseHandle(handle)
print stdout_value
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Re: subprocess: reading from stdout hangs process termination, waiting for ENTER keyboard signal
On 14 Apr, 18:52, MRAB wrote:
> giohappywrote:
> > Hello everyone.
> > I'm trying to use subprocess module to launch a Windows console
> > application. The application prints some results to standard output
> > and then waits for the user to press any key to terminte. I can't
> > control this behaviour, as the application is not mine...
> > I'm stuck at the very first lines of my code. I'm trying to force
> > process termination (even with proc.terminate()), and it works only if
> > I don't read from stdout. If I do proc.stdout.read() the process
> > hangs, and I have to manually press the keyboard to interrupt it.
> > Probably it's due a low-level handle that is kept on the process
> > stdout, waiting for the keypress event...
>
> > How can I solve it?
> > Giovanni
>
> > --- Code excerpt---
>
> > proc = subprocess.Popen('the_app.exe',
> > shell=True,
> > stdout=subprocess.PIPE,
> > )
> > #stdout_value = proc.communicate()[0]
> > stdout_value = proc.stdout.read()
> > PROCESS_TERMINATE = 1
> > handle = win32api.OpenProcess(PROCESS_TERMINATE, False, proc.pid)
> > win32api.TerminateProcess(handle, -1)
> > win32api.CloseHandle(handle)
> > print stdout_value
>
> Try this:
>
> proc = subprocess.Popen('the_app.exe',
> shell=True,
> stdin=subprocess.PIPE,
> stdout=subprocess.PIPE,
> )
> stdout_value = proc.communicate("\n")[0]
MRAB, I've tried that too but no result... I still have to press a
keybord key to terminate (the classical "Press any key to continue")
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Re: subprocess: reading from stdout hangs process termination, waiting for ENTER keyboard signal
On 15 Apr, 11:20, Kushal Kumaran wrote:
> On Wed, Apr 15, 2009 at 1:20 PM,giohappy wrote:
> > On 14 Apr, 18:52, MRAB wrote:
> >> giohappywrote:
> >> > Hello everyone.
> >> > I'm trying to use subprocess module to launch a Windows console
> >> > application. The application prints some results to standard output
> >> > and then waits for the user to press any key to terminte. I can't
> >> > control this behaviour, as the application is not mine...
> >> > I'm stuck at the very first lines of my code. I'm trying to force
> >> > process termination (even with proc.terminate()), and it works only if
> >> > I don't read from stdout. If I do proc.stdout.read() the process
> >> > hangs, and I have to manually press the keyboard to interrupt it.
> >> > Probably it's due a low-level handle that is kept on the process
> >> > stdout, waiting for the keypress event...
>
> >> > How can I solve it?
> >> > Giovanni
>
> >> > --- Code excerpt---
>
> >> > proc = subprocess.Popen('the_app.exe',
> >> > shell=True,
> >> > stdout=subprocess.PIPE,
> >> > )
> >> > #stdout_value = proc.communicate()[0]
> >> > stdout_value = proc.stdout.read()
> >> > PROCESS_TERMINATE = 1
> >> > handle = win32api.OpenProcess(PROCESS_TERMINATE, False, proc.pid)
> >> > win32api.TerminateProcess(handle, -1)
> >> > win32api.CloseHandle(handle)
> >> > print stdout_value
>
> >> Try this:
>
> >> proc = subprocess.Popen('the_app.exe',
> >> shell=True,
> >> stdin=subprocess.PIPE,
> >> stdout=subprocess.PIPE,
> >> )
> >> stdout_value = proc.communicate("\n")[0]
>
> > MRAB, I've tried that too but no result... I still have to press a
> > keybord key to terminate (the classical "Press any key to continue")
>
> If it actually is "Press any key to continue" rather than "Press Enter
> to continue", it is likely directly using the console using available
> low-level APIs, rather than reading from stdin. AFAIK, subprocess
> cannot handle that.
>
> --
> kushal
If also tried with SendKeys [1], wich uses the windows.h keybd_event
(), but it doesn't work... Ok, I leave this try, and look for a way to
wrap the application in a bat file, hoping to succesfuly simulate the
keypress event inside it.
[1] http://www.rutherfurd.net/python/sendkeys/
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Re: subprocess: reading from stdout hangs process termination, waiting for ENTER keyboard signal
On 15 Apr, 11:38, giohappy wrote:
> On 15 Apr, 11:20, Kushal Kumaran wrote:
>
>
>
> > On Wed, Apr 15, 2009 at 1:20 PM,giohappy wrote:
> > > On 14 Apr, 18:52, MRAB wrote:
> > >> giohappywrote:
> > >> > Hello everyone.
> > >> > I'm trying to use subprocess module to launch a Windows console
> > >> > application. The application prints some results to standard output
> > >> > and then waits for the user to press any key to terminte. I can't
> > >> > control this behaviour, as the application is not mine...
> > >> > I'm stuck at the very first lines of my code. I'm trying to force
> > >> > process termination (even with proc.terminate()), and it works only if
> > >> > I don't read from stdout. If I do proc.stdout.read() the process
> > >> > hangs, and I have to manually press the keyboard to interrupt it.
> > >> > Probably it's due a low-level handle that is kept on the process
> > >> > stdout, waiting for the keypress event...
>
> > >> > How can I solve it?
> > >> > Giovanni
>
> > >> > --- Code excerpt---
>
> > >> > proc = subprocess.Popen('the_app.exe',
> > >> > shell=True,
> > >> > stdout=subprocess.PIPE,
> > >> > )
> > >> > #stdout_value = proc.communicate()[0]
> > >> > stdout_value = proc.stdout.read()
> > >> > PROCESS_TERMINATE = 1
> > >> > handle = win32api.OpenProcess(PROCESS_TERMINATE, False, proc.pid)
> > >> > win32api.TerminateProcess(handle, -1)
> > >> > win32api.CloseHandle(handle)
> > >> > print stdout_value
>
> > >> Try this:
>
> > >> proc = subprocess.Popen('the_app.exe',
> > >> shell=True,
> > >> stdin=subprocess.PIPE,
> > >> stdout=subprocess.PIPE,
> > >> )
> > >> stdout_value = proc.communicate("\n")[0]
>
> > > MRAB, I've tried that too but no result... I still have to press a
> > > keybord key to terminate (the classical "Press any key to continue")
>
> > If it actually is "Press any key to continue" rather than "Press Enter
> > to continue", it is likely directly using the console using available
> > low-level APIs, rather than reading from stdin. AFAIK, subprocess
> > cannot handle that.
>
> > --
> > kushal
>
> If also tried with SendKeys [1], wich uses the windows.h keybd_event
> (), but it doesn't work... Ok, I leave this try, and look for a way to
> wrap the application in a bat file, hoping to succesfuly simulate the
> keypress event inside it.
>
> [1]http://www.rutherfurd.net/python/sendkeys/
Sorry, SendKeys is the solution. I was using it in the wronk place in
my script...
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