VsCode appears to keep running wxPython app when it should have stopped - visual-studio-code

In my VsCode wxPython application under Windows, I bind the close event to my function as follows:
import wx
class MyFrame(wx.Frame):
def __init__(self, title):
wx.Frame.__init__(self, None, title = title, pos = (150, 0))
self.Bind(wx.EVT_CLOSE, self.OnClose)
# Other stuff ...
def OnClose(self, event):
print("closing")
self.Destroy()
app = wx.App()
top = MyFrame("My App")
top.Show()
app.MainLoop()
print("done")
Now I can see it's being called when I close the top level window (a wxFrame) as the closing and done messages appear. The window itself also disappears.
However VsCode thinks the application is still running since it has the debug controls still available:
and the console that ran it (Python debug console) does not come back with a prompt. It's not until I click on the stop button does the command prompt reappear in that console.
Interestingly, if I run the application outside of VsCode, it exits correctly, returning to the command prompt.

Try wx.Exit() in case you have something still open/running without realising it.
wx.Exit()
Exits application after calling wx.App.OnExit .
Should only be used in an emergency: normally the top-level frame should be deleted (after deleting all other frames) to terminate the application. See wx.CloseEvent and wx.App.

Related

Is there any option of running an Anylogic simulator without opening any UI window?

I'm in a project in which I have to run an Anylogic simulator multiple times. I made an script to modify the input data, run the simulator and then store the output data just before the next simulation run.
The idea is to externally run the simulation (from a python file). The problem is that, when the simulation ends, the simulation window doesn't close automatically so the python file won't continue executing.
I´ve tried to run the simulator without showing the animation of the simulation but still opens a window so it doesn´t work for my purpose.
I don´t know if there is an option in Anylogic to export a model that automatically closes the window once the simulation is completed or if there is any way of creating a simulator that runs without opening any window.
Thank you.
Unfortunately there is no such solution. Even if you can run without UI in Linux, it will not automatically close once the run is complete. I use a workaround:
It is a Python script that scans the outputs folder every 5 seconds and if there are changes in the files, it closes the AnyLogic file. Use this as an inspiration::
from time import sleep
from utils.data.fileSystem import FileSystem
def sync_polling_folder(path, predicate, delay_sec):
print('checking under ' + path + ' folder')
beginning = FileSystem.stat(path)
old = beginning
new = beginning
def two_files_are_different():
return not predicate(str(old), str(new))
def the_process_has_not_begun():
return str(new) == str(beginning) or str(old) == str(beginning)
# if two folders are the same, quit (means no-changes = finished)
# but if they are equal because process never started, keep going
while two_files_are_different() or the_process_has_not_begun():
print('[sleeping] because files are not written yet.')
sleep(delay_sec) # main thread waiting
old = new
new = FileSystem.stat(path)
print('[anylogic] ready to be killed')
return True

python Gtk app failed with this error xcb xlib threads sequence lost failed

I had a pyGObject app and I run that. all things work fine until on a button clicked signal I need to run a def. it has a long loop and I run that with the
def on_launch_btn_clicked(self,button):
_thread.start_new_thread(launch,["thread"])
def launch(thread):
lines_list = open("../line.txt").split()
for line in lines_list:
select = machinestate.objects.get(id=1)
if not select.pause:
#my process
else:
def pause_lcd()
return "pause" #it for come out of def and close thread but I don't know it close that or not
this loop is in another .py file
function it works like a charm, next I had a pause button it changes database pause field to True and my loop every iteration check database to saw what is changed. when it saw pause is True it run
def pause_lcd():
app = app_list[0]
app.pause_action()
I run Gtk app in this def
app_list = list()
def main(thread):
app = GUI()
app_list.append(app)
Gdk.threads_init()
Gtk.main()
in my GUI class I have pause_action method
def pause_action(self):
self.pause_btn.set_sensitive(True)
self.pause_btn.hide()
self.resume_btn.show()
when I clicked on pause button some time I got this error
[xcb] Unknown sequence number while processing queen
[xcb] Most likely this is a mulity-threaded client and XinitThreads has not been called
[xcb] Aborting, sorry about that
pyhton: ../../src/xcb_io.c:263 poll_for_event: Assertion '!xcb_xlib_threads_sequence_lost failed.
I had a bunch of thread side this threads like machine info, clock, machine temp and ...
what I do wrongs??
PS: this app run in a Django project and I use Django model in this it is an app of Django but it runs a Gtk app
I suspect that something with the XCB or the X11 server is wrong (bug). I received the same error message from different applications on a specific X server (using X11 over ssh).
Error message with emacs:
[xcb] Unknown sequence number while processing queue
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
emacs: xcb_io.c:263: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.
Error message with eclipse:
[xcb] Unknown sequence number while processing queue
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
java: xcb_io.c:263: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.

wxPython window randomly freezes on RPi and acts weird afterwards

This Problem occurs on the RPi (3B+, Raspbian Buster) only. I run the program on my Mac without any problems.
Short description of my program:
After entering the mainloop, the program enters a second thread with another loop (call it requestloop) when the designated button is pressed. The requestloop can be left by pressing the button again. This requestloop requests a xml table via url every 10 seconds which is then parsed with ElementTree, sorted and displayed in a wx.grid.Grid. I use grid.ForceRefresh to make sure the grid is updated.
I hope the following snippet helps to understand the above:
def on_btnrun(self, event):
global run
if self.btnrun.Label == "Start":
run = True
thrupt = threading.Thread(target=self.thrupdate)
thrupt.start()
self.btnrun.SetLabel("Ende")
elif self.btnrun.Label == "Ende":
run = False
self.btnrun.SetLabel("Start")
def thrupdate(self):
while run is True:
reset()
self.grid.ClearGrid()
update(self.grid)
self.grid.ForceRefresh()
time.sleep(10)
Problem:
Now as mentioned in the title the whole wx Window freezes after passing the requestloop between roughly 5 and 20 times. This happens completely randomly, I could not find any regularities. The program keeps running though, for it still prints the output in the terminal every cycle (I added this function for testing).
When I now open another window (eg. menu dropwdown) which lays over the wx Window it will be copied onto the wx Window and stay there after I closed it.
Here are some Images to better understand what I mean (ignore all other widgets that I didn't mention, they are just nonfunctional placeholders).
Image of the wx Window before it freezes
Image of the wx Window after it freezes
Image of the wx Window after opening and closing the dropdown menu
Extra-Info: while building wxPython on the RPi I got some warnings and everytime I run the program I get the following one (it says the actual time instead of time):
(program.py:1666): Gtk-Critical **: time: gtk_distribute_natural_allocation: assertion ‚extra_space >= 0‘ failed
Question:
I have no idea why any of this happens. Is wxPython not stable on Raspbian? Or did the build partly fail? Or is the RPi not having enough rendering capacity?
Solved it by using wx.CallAfter in the details of the update() method.

Stop VFP from showing dialog boxes when errors occur

I am trying to call an existing VFP 6 application using Jacob which is a COM bridge for Java.
val vfp = new Application(new ActiveXComponent("VisualFoxPro.Application").getProperty("Application").toDispatch())
vfp.setVisible(false)
try {
vfp.doCmd("do my.exe with myconfig.txt")
} catch {
case t: Throwable => t.printStackTrace
} finally {
vfp.doCmd("close data")
vfp.doCmd("clear all")
vfp.doCmd("clear")
vfp.quit
vfp.safeRelease
}
When there are no error conditions this code executes well and generates the expected .dbfs. The problem is that when an error occurs (.dbf not found, file in use by another user, etc) a GUI window pops up and stops execution of the program until I use the mouse to cancel it. I want this program to run on a server with no user interaction so this won't work.
How can I gracefully handle the errors preferably without making a change to the VFP 6 program?
Since you have the source code for VFP6, I would suggest looking into
SYS(2335,0)
Sys 2335 is used to identify if the program is running in an "unattended" mode, any such popup dialog boxes will throw an error and prevent an actual "hit" ok/cancel/whatever button to continue. This includes popup window prompting user to pick a table.
I'm not positive of when it was made available as I had limited use of it. Like you, when dealing with a COM server under IIS and obviously nobody there to respond.
Start JVM in headless mode, catch HeadlessException or something. Or, write a Java program that will execute your GUI program using Runtime, and restart in a case of parsed errors in console.

Output to command-line if started from command line

I'm writing an application that can be started either as a standard WinForms app or in unattended mode from the command-line. The application was built using the VS 2k5 standard WinForms template.
When the application is executed from the command-line, I want it to output information that can be captured by the script executing the application. When I do this directly from Console.WriteLine(), the output does not appear, although it can be captured by piping to a file.
On the other hand, I can force the application to pop up a second console by doing a P/Invoke on AllocConsole() from kernel32. This is not what I want, though. I want the output to appear in the same window the application was called from.
This is the salient code that allows me to pop up a console from the command line:
<STAThread()> Public Shared Sub Main()
If My.Application.CommandLineArgs.Count = 0 Then
Dim frm As New ISECMMParamUtilForm()
frm.ShowDialog()
Else
Try
ConsoleControl.AllocConsole()
Dim exMan As New UnattendedExecutionManager(ConvertArgs())
IsInConsoleMode = True
OutputMessage("Application started.")
If Not exMan.SetSettings() Then
OutputMessage("Execution failed.")
End If
Catch ex As Exception
Console.WriteLine(ex.ToString())
Finally
ConsoleControl.FreeConsole()
End Try
End If
End Sub
Public Shared Sub OutputMessage(ByVal msg As String, Optional ByVal isError As Boolean = False)
Trace.WriteLine(msg)
If IsInConsoleMode Then
Console.WriteLine(msg)
End If
If isError Then
EventLog.WriteEntry("ISE CMM Param Util", msg, EventLogEntryType.Error)
Else
EventLog.WriteEntry("ISE CMM Param Util", msg, EventLogEntryType.Information)
End If
End Sub
Raymond Chen recently posted (a month after the question was posted here on SO) a short article about this:
How do I write a program that can be run either as a console or a GUI application?
You can't, but you can try to fake it.
Each PE application contains a field
in its header that specifies which
subsystem it was designed to run
under. You can say
IMAGE_SUBSYSTEM_WINDOWS_GUI to mark
yourself as a Windows GUI application,
or you can say
IMAGE_SUBSYSTEM_WINDOWS_CUI to say
that you are a console application. If
you are GUI application, then the
program will run without a console.
The subsystem determines how the
kernel prepares the execution
environment for the program. If the
program is marked as running in the
console subsystem, then the kernel
will connect the program's console to
the console of its parent, creating a
new console if the parent doesn't have
a console. (This is an incomplete
description, but the details aren't
relevant to the discussion.) On the
other hand, if the program is marked
as running as a GUI application, then
the kernel will run the program
without any console at all.
In that article he points to another by Junfeng Zhang that discusses how a couple of programs (Visual Studio and ildasm) implement this behavior:
How to make an application as both GUI and Console application?
In VisualStudio case, there are actually two binaries: devenv.com and devenv.exe. Devenv.com is a Console app. Devenv.exe is a GUI app. When you type devenv, because of the Win32 probing rule, devenv.com is executed. If there is no input, devenv.com launches devenv.exe, and exits itself. If there are inputs, devenv.com handles them as normal Console app.
In ildasm case, there is only one binary: ildasm.exe. It is first compiled as a GUI application. Later editbin.exe is used to mark it as console subsystem. In its main method it determines if it needs to be run as console mode or GUI mode. If need to run as GUI mode, it relaunches itself as a GUI app.
In the comments to Raymond Chen's article, laonianren has this to add to Junfeng Zhang's brief description of how Visual Studio works:
devenv.com is a general purpose console-mode stub application. When it runs it creates three pipes to redirect the console's stdin, stdout and stderr. It then finds its own name (usually devenv.com), replaces the ".com" with ".exe" and launches the new app (i.e. devenv.exe) using the read end of the stdin pipe and the write ends of the stdout and stderr pipes as the standard handles. Then it just sits and waits for devenv.exe to exit and copies data between the console and the pipes.
Thus even though devenv.exe is a gui app it can read and write the "parent" console using its standard handles.
And you could use devenv.com yourself for myapp.exe by renaming it to myapp.com. But you can't in practise because it belongs to MS.
Update 1:
As said in Michael Burr answer, Raymond Chen recently posted a short article about this. I am happy to see that my guess was not totally wrong.
Update 0:
Disclaimer: This "answer" is mostly speculation. I post it only because enough time has passed to establish that not many people have the answer to what look like a fundamental question.
I think that the "decision" if the application is gui or console is made at compile time and not at runtime. So if you compile your application as gui application, even if you don't display the gui, its still a gui application and doesn't have console. If you choose to compile it as console application then at minimum you will have a console windows flashing before moving to gui "mode". And I don't know if it is possible in managed code.
The problem is fundamental, I think, Because a console application has to take "control" of the calling console application. And it has to do so before the code of the child application is running.
If you want to check if your app is started from the command line in .NET, you can use Console.GetCursorPosition().
The reason that this works is that when you start it from the command line, the cursor moves away from the initial point ((0, 0)) because you typed something in the terminal (the name of the app).
You can do this with an equality check (code in C#):
class Program
{
public static void Main
{
if (Console.GetCursorPosition() == (0, 0))
{
//something GUI
}
else
{
//something not GUI
}
}
}
Note: You must set the output type to Console Application as other output types will make Console.GetCursorPosition() throw an exception.