My program is for rendering an animation clip, but every frame has to be computed before rendered. It seems that if the computation takes seconds, windows starts to recognize my process as "not-responding" and refuses to render anything any more, although in the Task Manager, the process itself appears to switch between "running" and "not-responding" all the time.
I have been searching solutions online for a while. A lot people suggested to delete some registry entries:
HKEY_USERS.DEFAULT\Control Panel\Desktop\HungAppTimeOut
HKEY_USERS.DEFAULT\Control Panel\Desktop\WaitToKillAppTimeOut
HKEY_CURRENT_USER\Control Panel\Desktop\HungAppTimeOut
HKEY_CURRENT_USER\Control Panel\Desktop\WaitToKillAppTimeOut
HKEY_CURRENT_USER\Control Panel\Desktop\WaitToKillServiceTimeOut
But I could not find those entries. And according to the descriptions, all those entries mentioned are about controlling how long the system waits after the user requires to end a process or log off to kill a process or service. So they are not what exactly I want. I guess there must be some threshold to control when the system should start to consider one process as "not responding" and I want to change that threshold into a slightly bigger one.
Thanks for your attention and time, any suggestion is welcome!
You should avoid hanging the UI in the first place by doing your processing/computation in a background thread, rather than on the UI thread. If you're using WinForms or WPF, use a BackgroundWorker.
See here for some BGWorker examples: WPF Threads: Build More Responsive Apps With The Dispatcher
I'm using Microstation to build a model, so this is a similar process. About half way through building the model everything freezes up and adds the "application not responding" message to the title.
Disabling the Desktop Window Manager Session Manager worked for me, however in a enterprise environment this is not the best solution, as common users don't have rights to access the services panel.
Try disabling Desktop Window Manager Session Manager from services. Worked for me. That also disabled aero theme by the way. Win7 really looks fancy but it has to operate normally.
Related
On Microsoft Windows (8), I would like to start a process, and prevent it from showing any windows at all. Alternatively, to force-close any windows that are shown. Is there a way to do this?
My application is this: I'm running an automated (nunit) test suite on my continuous integration (teamcity) server. The code under test is also used by an interactive application. Developers occasionally slip in a dialog with a user prompt, without realising what they are doing. This causes the CI process to stop, waiting for user input which never comes. I'd like to be able to dismiss any dialog that appears, or prevent them from being shown.
Even better would be to force an exception at this point, so that the test would also fail.
In my case, this is a C# application, and the dialogs shown are Windows Forms or WPF dialogs.
I did find a couple of similar questions. However each turned out to be solving a slightly different problem.
Stop a process from showing a window from C# (solves a different problem)
Preventing blocking dialogs/message boxes/hanging GUI from non-interactive processes on Windows? (promising solution but C++-specific)
Prevent child process from creating visible windows? (solves a different problem)
Have you considered asking your development team to have a "no dialog" mode of the app for testing purposes? Perhaps if you stopped referring to them as (!!*&%) they would be more inclined to partner with you. ;) Afterall, you do work at the same company on the same product :)
In any case, without a dev-specific solution, consider having a another app (process or thread) that continually sleeps for a few seconds, wakes up and looks for a modal dialog in your application. You can use APIs such as FindWindow to identify when a modal dialog has popped up. (Use Spy++ to get the class name for windows created by MessageBox and CreateDialog APIs).
I'm writing WPF application
application targets all sort of windows and low performance computers
so I want to write launcher/splash screen for it which will be displayed before application loads
I'm not sure what language to use or what technology
I want it to be very fast and lightweight
can you suggest anything ?
Displaying a flash screen is as easy as popping up a dialog. If the dialog has the various resources such as bit maps already included then it is quite fast. However one issue that will determine this speed is how much other stuff is being initialized at application startup before the code is hit to display the dialog.
So one option would be to have a very simple application that does nothing more than display the flash screen and then start up the actual application. A simple Windows dialog application would do that. You would need to figure out how to synchronize the actual application finishing its initialization and the launching application stopping if you choose this route. There are several techniques for this and the most likely would be to use an interprocess mutex or perhaps just look for a file to be created.
For a point of sale I work with that is launched as part of turning on the terminal we ran into problems in which the application would start before some required system services such as database manager were up and running.
We have found that some environments require much more time than others so a registry variable makes it easy to tweak the delay in the field.
So as part of the application initialization what we did was that when the application starts up, it displays a dialog with a progress bar. The progress bar does a count up and we have a loop that does a one second sleep then increments the progress bar.
The number of seconds to wait is a registry setting for the application with a default value.
One problem we ran into was that when doing development and testing in a debugger, the default value was way too long for impatient programmers wanting to get started so we have condition compile so that if it is a debug compile, the delay is set to a couple of seconds. Otherwise the default is 10 seconds. However it can be changed with a change in the registry value.
See also this Stackoverflow about a launcher.
If you want something realy fast and lightweight, C would be nice.
If you dont want to learn C, you can also make a console application with .NET and C# it's fast too
Edit for comment: You can use a library like SDL wich is very fast and powerfull, and can draw images from a console application.
I have been working on windows automation and monitoring.
What exactly happens when I lock the screen of a windows machine?
I am working with Windows 7 at the moment, are there big differences to the behavior if I switch to Vista or the server versions?
Is there still a desktop that can be accessed via api's?
I know that i can still send key strokes and mouse clicks to specific windows (via ControlSend and ControlClick), but there seems to be no "desktop" itself.
Could someone shed some light on this whole thing or point me at a readable source where I could get an overview over the topic?
Basically what happens is that Windows switches to the secure desktop, makes it the current one, so input is now associated with it.
The old desktop remains where it was: all the HWNDs on the desktop are still there, and any thread attached to that desktop can still access those HWNDs, get their location, and so on. You can still send messages to windows on this desktop, so long as the thread sending the message is also on that desktop.
However, since the desktop is now inactive, it cannot receive input. GetForegroundWindow will return NULL (IIRC), and you can't use SendInput any longer, since input now belongs to [a thread on] a different desktop; no controls on that inactive desktop can receive focus.
Note that sending keypress messages to a control that doesn't have focus can sometimes cause unexpected behavior, since the app or control generally never expects to receive keyboard input without getting the focus first. (This can be problematic for controls that set up some sort of input context in WM_SETFOCUS and clear it up in WM_KILLFOCUS, for example.)
In short, the UI is still there: you can do certain queries against it, but you can no longer automate it as you could on a regular desktop by sending input, and some other functions that relate to focus or input may fail.
I'm not super familiar with AutoHotKey, but the name and description of functionality suggests that it's heavily reliant on the underlying Win32 SendInput API. This won't work at all for keyboard input when a desktop is inactive.
For a reasonable overview of how desktops work and how they relate to winstations, the locked desktop, and so on, check out the Desktop article on MSDN.
One issue that I've run into in the past with desktops and automation is: how to I leave a long-running test that's using some form of user input automation (mouse, keyboard simulation), but still lock my PC so that someone can't just walk by and interfere with it. Once you lock the PC, the desktop is inactive, and so the automation stops working. A similar issue happens if the screensaver kicks in: the desktop switches, and the automation fails.
One solution is to use two PCs: let's call them Main and Test: from Main, open a remote terminal services client onto the Test machine, and then run the automated test on the test machine, but from a terminal services client window on the Main machine. Now the cool part: you can minimize that TSC window, or even lock the Main machine (or let the screensaver kick in), and that virtual session will continue working, thinking that it is still active - it's just that nobody is paying it any attention. This is one way to create a "connected" session with an active desktop, but one that no-one can interfere with, because it's protected behind the locked desktop of the Main machine.
I don't know the details, but I believe the lock screen constitutes a separate "desktop" and maybe also a separate "window station" (as I understand it a window station is merely a container for desktops). The MSDN section on window stations should hopefully be useful: http://msdn.microsoft.com/en-us/library/windows/desktop/ms687098%28v=vs.85%29.aspx
In order to access a desktop, you will need to use the regular windows api's from a thread that is on that desktop. SetThreadDesktop would probably be the easiest way to do that in C, as long as the desktop isn't on a different window station.
Unfortunately, this is already difficult for a regular privileged application, and using AutoHotkey complicates it even more. Since you don't have control over threads or over process initialization, you will probably have to create a new process in the other desktop (you can do this using the CreateProcess API, which appears to have a wrapper available for AHK to which you can supply a desktop name: http://www.autohotkey.com/forum/topic1952.html). Your process will need special privileges to do this; I'm not sure that even running as Administrator is enough.
TL;DR - How does the Spy++ tool really construct its process list?
Stage
We have an MFC desktop application (running on Windows XP) that is hanging in that it doesn't react to any user input anymore. It is redrawn when switching to it via alt-tab however. (It does receive WM_SETFOCUS, WM_ACTIVATE, etc. It apparently does not receive any mouse or keyboard messages.)
Since the app is hanging in some limbo, we pulled a few process dumps, but these were of little help so far. Enter:
Spy++
We used Spy++ to find the information I gave above about the window messages this application seems to be processing. We did this by Opening the Windows View and selecting our application Window and in the Messages properties selected Windows of same process and Messages to View : Select All.
However we first tried to view all messages of this process by opening the Processes View of Spy++ and our application is not shown in this process list. Cross checking on another PC where the app is running normally, the process is also normally shown in the processes list of Spy++.
Can anything about the misbehaving app be inferred from the fact that the process is not shown in Spy++'s Process View, but the main window of the app is shown in the Windows View. Why would a process with a main window that is visible not be shown in Spy++'s Processes View?
The process is listed in Task Manager and in the Attach Process Window of Visual Studio 2005. So these tools apparently use a different method to list processes than Spy++ ... ?
The system where the app is currently hanging is a Windows XP SP2 system and we've used the Spy++ Utility that comes with Visual Studio 2005.
The behavior does recur occasionally, but only after the App has been running for several days!
Running Vista or later? Your process is probably elevated and Spy++ is not. Newer versions of Spy++ require elevation. So, try elevating Spy++ explicitly and see if that helps.
Yes, of course things can be inferred from this. Don't take anything I say too seriously in this context, I'd have to go look at the code. But I believe that Spy goes off and looks at the EnumProcesses API. (http://msdn.microsoft.com/en-us/library/ms682629.aspx)
So, if your process isn't showing up there... hrm.
But, what is different between the system where it's working and the one where it's not?
Spy++ requires the following two values in the registry to be disabled (0) to display the processes/threads list AT ALL:
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib
HKLM\System\CurrentControlSet\Services\PerfProc\Performance
Disable Performance Counters -> either 0 or not present
Was going insane trying to find out why it refused to display them. It's some kind of bad joke - this debugger requires itself a debugger to get it working! Not that WinDBG would display any meaningful info, MS doesn't even provide a symbol file on their symbol server, pfft.
Anyway, maybe it doesn't display processes that have their performance counters disabled, because I think, this can be set on individual basis, at least for services, like:
HKLM\SYSTEM\CurrentControlSet\Services\.NET CLR Networking\Performance
Disable Performance Counters
So it's basically always a value of the "Performance" subkey. All this stuff is undocumented, it makes use of advapi32.dll functions like "PerfRegQueryValue" and "PerfRegQueryInfoKey"... don't ask me.
One solution that one could suggest is to periodically look for a special 'Screen-saver' desktop, and if it's present then count it as a running screensaver.
But apparently this is not the case for all screensavers as with some the mentioned desktop is always present.
Are there more reliable solutions for this?
See the WINAPI function SystemParametersInfo() with the SPI_GETSCREENSAVERRUNNING parameter. It's the only documented way to detect whether the screen saver is currently running. (You can also find out if a screen saver is even enabled, get and set the timeout value, and start the screen saver using this function.)
I think the key is to identify the screensaver by its window class ("WindowsScreenSaverClass"). I found this page
How do I start, detect and stop screen savers? that has some code examples and explanations.
HOW TO: Determine If Screen Saver Is Running by Using Visual Basic 6.0
I know this is for VB6, but it's bound to be a good place to start.
This is my implementation of screen saver event detection.
Notes:
SPI_GETSCREENSAVERRUNNING detects Windows Event id 4802 and 4803 which weren't accurate in my case, see my problem hence user idle time calculation is added
GetLastInputInfo apparently doesn't work if process is a service.
search processes for a process with .scr in its .MainModule.FileName