windows-cmd shell doesn't reflect _winreg changes
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haugh
#1 / 4
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 windows-cmd shell doesn't reflect _winreg changes hi
i'm using _winreg to 'hard-change' and environmental variable in
windows. the change is 'successful': regedit correctly reflects the
changes, and crtl panel > system > properties envronmental vars have
been correctly changed. but, when i start a cmd shell (dos), the
shell evironment still reflects the old values until i manually open
the env vars cntrl panel and click 'ok'. anyone?
thanks
hawkeye
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| Mon, 19 Sep 2005 08:09:21 GMT |
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Ben Hutching
#2 / 4
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windows-cmd shell doesn't reflect _winreg changes Quote:
> hi > i'm using _winreg to 'hard-change' and environmental variable in
> windows. the change is 'successful': regedit correctly reflects the
> changes, and crtl panel > system > properties envronmental vars have
> been correctly changed. but, when i start a cmd shell (dos), the
> shell evironment still reflects the old values until i manually open
> the env vars cntrl panel and click 'ok'. anyone?
This is really a Win32 programming issue rather than a python one.
However, I do vaguely remember this one.
Environmental variables are normally passed to a new process by the
process that creates it, and they can never be updated from outside
a process. The exception to this is that Windows Explorer (and any
other program that wishes to) will read those initial environment
variables out of the registry when notified of a change in settings.
The changes will then be passed on to any program started by Explorer
afterwards.
Here's the Python code:
import win32con, win32gui
win32gui.SendMessage(
win32con.HWND_BROADCAST, win32con.WM_SETTINGCHANGE, 0, 0)
You might want to use SendMessageTimeout instead of SendMessage.
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| Tue, 20 Sep 2005 02:43:36 GMT |
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haugh
#3 / 4
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windows-cmd shell doesn't reflect _winreg changes Many thanks Ben!!
Quote:
> > hi > > i'm using _winreg to 'hard-change' and environmental variable in
> > windows. the change is 'successful': regedit correctly reflects the
> > changes, and crtl panel > system > properties envronmental vars have
> > been correctly changed. but, when i start a cmd shell (dos), the
> > shell evironment still reflects the old values until i manually open
> > the env vars cntrl panel and click 'ok'. anyone?
> This is really a Win32 programming issue rather than a Python one.
> However, I do vaguely remember this one.
> Environmental variables are normally passed to a new process by the
> process that creates it, and they can never be updated from outside
> a process. The exception to this is that Windows Explorer (and any
> other program that wishes to) will read those initial environment
> variables out of the registry when notified of a change in settings.
> The changes will then be passed on to any program started by Explorer
> afterwards.
> Here's the Python code:
> import win32con, win32gui
> win32gui.SendMessage(
> win32con.HWND_BROADCAST, win32con.WM_SETTINGCHANGE, 0, 0)
> You might want to use SendMessageTimeout instead of SendMessage.
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| Mon, 26 Sep 2005 03:08:23 GMT |
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haugh
#4 / 4
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windows-cmd shell doesn't reflect _winreg changes follow up:
the SendMessage command as suggested below didn't actually work. I
did some poking around on the win32 newsgroup and eventually found MS
Knowledge Base's Q104011, "HOWTO: Propagate Environment Variables to
the System". it suggests:
SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, 0, (LPARAM)
"Environment", SMTO_ABORTIFHUNG, 5000, &dwReturnValue);
which is pythonified to:
win32gui.SendMessageTimeout(win32con.HWND_BROADCAST,
win32con.WM_SETTINGCHANGE, 0, "Environment",
win32con.SMTO_ABORTIFHUNG, 5000)
and actually works. you still have to close the cmd shell and reopen
it, but this is much faster than going through the whole process
manually.
Quote:
> Many thanks Ben!!
> > > hi
> > > i'm using _winreg to 'hard-change' and environmental variable in
> > > windows. the change is 'successful': regedit correctly reflects the
> > > changes, and crtl panel > system > properties envronmental vars have
> > > been correctly changed. but, when i start a cmd shell (dos), the
> > > shell evironment still reflects the old values until i manually open
> > > the env vars cntrl panel and click 'ok'. anyone?
> > This is really a Win32 programming issue rather than a Python one.
> > However, I do vaguely remember this one.
> > Environmental variables are normally passed to a new process by the
> > process that creates it, and they can never be updated from outside
> > a process. The exception to this is that Windows Explorer (and any
> > other program that wishes to) will read those initial environment
> > variables out of the registry when notified of a change in settings.
> > The changes will then be passed on to any program started by Explorer
> > afterwards.
> > Here's the Python code:
> > import win32con, win32gui
> > win32gui.SendMessage(
> > win32con.HWND_BROADCAST, win32con.WM_SETTINGCHANGE, 0, 0)
> > You might want to use SendMessageTimeout instead of SendMessage.
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| Sun, 16 Oct 2005 05:52:56 GMT |
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