I have a small app that I'm trying to build against windows machines. The program creates an OpenVPN connection. If I build the program and run it it first opens a console as the program output. If I pass the -w parameter to pyinstaller to not build it with a console attached the program fails to run at all. It opens allright but the vpn connection is never created.
With the console everything works perfect.
I also have a basic logging for the application in place to see where my code might stop and nothing gets written. With console on my program spits out all kinds of logs.
I just don't know why my program could be performing perfectly with a console but doing nothing without one. Any ideas?
Gonna answer this myself. Make sure you don't print anything and also you redirect all stdout to a logger, file or whatever else instead of the console.
I was having a similar problem, but couldn't find any print/stdout statements going to console. I was using subprocess.Popen and redirecting stdout=subprocess.PIPE. I subsequently added stderr=subprocess.STDOUT and stdin=subprocess.PIPE and my program worked. This page (Python subprocess.call() fails when using pythonw.exe) on subprocess failures helped me get it working.
Related
I have been making an application using Javafx, and have finished the project turning it into an application. However, when I try to run the application it immediatley crashes with know error messages, nothing is printed to the console. As a note, the .jar file runs if clicked. This has led me to believe that the problem is with my file structure namely the fact that their are 2 binary files in the Java folder.
Here is my .app packages contents:
A fix to my problem would be nice, however beyond that how should one go about debugging this sort of thing, I can not find any log messages, can it be done?
Edit: Nothing is printed when in terminal I use open -a ApplicationName and the application crashes. And here is my info.plist.
I understood that anything to standard out (System.out) would appear in the Java Console window (when it's enabled). I spotted somewhere though that there might be situations where this isn't try, for example, from Swing apps. Is that the case?
Basically, what situations or setups wouldn't I expect to see standard output in the console? Is there a difference in behavior running on the JDK rather than explicitly on the JRE for example? javaw.exe?
ps, I understand how to display the Console in the Java settings but I'm curious as I've managed to create an application, run as an executable jar, that doesn't start the console despite some calls to System.out) on Windows 7.
The only way you wouldn't see System.out output in the console is if the method System.setOut has been invoked. This method is invoked to redirect output to the graphical Java Console, but I don't know of any other realistic circumstance in which it would be redirected away from the Java Console unless you do so voluntarily.
Depending on terminal settings it can happen that the output is not written until a newline character is sent as well. So if you do System.out.print("test") it might not appear immediately.
On Windows this is usually not the case, but on Unix terminals this is quite common.
Perhaps you use javaw to start virtual machine, this version will not show console messages. You can use java to start the virtual machine, which will show the console message.
javaw is intended for apps with windows, java is intended for console apps.
Same thing happened to me. I could not get System.out.println or Logger.debug either on console.
If you are on a huge project in Eclipse or whatever, you can read below.
Solution: I realized that I had not committed jars and some java files to SubVersioN on network. thats all. Project had not been compiled.
One situation I can think of is to invoke System.setOut(null) (orSystem.setOut(any OutputStream other than System.out or System.err)) then the console, if exists, would show nothing.
So in a console .Net application I can watch all my log4net events stream by with (the powershell command) get-content .\log.log -Wait which is similar to the linux tail command and I assume uses FileSystemWatcher under the hood.
For some reason, whenever I have an asp.net Mvc application this will not work. To be clear, the log file IS written to. I can get-content .\log.log as many times as I want and get the most recent results, but with the -wait parameter I never see the changes scroll past.
Does anyone have any insight into what might be going on here?
UPDATE: found a working solution for my case, not sure whether this would help you out.
Instead of using PowerShell, I downloaded win-bash and now I'm using this familiar Unix command which works perfectly for me.
tail -f access.log
I'm not that familiar with .Net programming. Could it be a working solution in your case to use win-bash project's bash.exe instead of PowerShell?
I am experiencing similar issue when trying to "tail" Apache access log in PowerShell.
Get-Content .\access.log -Wait
I noticed that when my Apache HTTP server is running, it has a handle open to acccess.log and -Wait doesn't work. Stopping HTTP server releases the handle and when I made manual changes to access.log using text editor my PowerShell window immediately reflected changes in the console.
So I assume if some other program has a handle open to the file, changes are not reflected to console. Unfortunately I haven't found a way around this issue so far.
I have a GUI program that opens a Windows console in a separate window to display output and accept user input. My development environment is Qt 4.7.1 with mingw. The console works fine, until I try to run the program in Qt's debugger (gdb); then, although AllocConsole succeeds, and GetStdHandle appears to return a valid handle (0x000000d8), any attempt to use the handle causes Windows error 6 (invalid handle).
So I can't debug my program. Which is a pain, because it has some serious bugs. The problem may be that gdb's console prevents me opening my own console; but then why do AllocConsole and GetStdHandle succeed? I upgraded to Qt Creator 2.0.94 (Qt 4.7.1), but it didn't help. Any ideas?
Update I have found that I can debug the program by running it without the debugger, and then attaching to it from Qt. Not ideal, but better than nothing.
Can't you use the standard output console, using
CONFIG += console
in the .pro file?
Hmm -- check this out:
A process can be associated with only one console, so the AllocConsole function fails if the calling process already has a console. A process can use the FreeConsole function to detach itself from its current console, then it can call AllocConsole to create a new console or AttachConsole to attach to another console.
Can you try running FreeConsole before you create yours?
I've written a c# windows app, that performs some DB intensive operations. (MySQL connector v6).
When running the project in Debug mode, everything works fine. However, when I run the prject in release mode, it sometimes quits operation midway - with no error message, nothing in the event logs etc.
What would be the best way to debug release mode - when everything works in debug mode?
Thanks for any help,
Bob
You can create a log file and have the application write lines to it with information of your choice, similarly to how the console may be used for debug purposes in a windows form application. You can write values of certain variables to this file, or even just write distinct phrases in select places of the code that will help you detect where the program is in execution when it fails.
Bobby is correct in asking about Application Event Log. If it is bombing on a .NET error, it will likely be logged.
If that doesn't give you anything, wrap the entire app in a try/catch block. On your exception handling, log the error (application log, file, etc...). Make sure when you log it to capture the call stack.
I've got exactly the same problem - application running in debug mode and fail in release. Try the following:
Wrap everything in Program.cs in try{}..catch{} block and it will show a reason
I don't know why but my application failed on Program.SetCompatibleTextRenderingDefault() function with message that it should be called before any instances on IWin32Window or something like that
It is very strange errors for me cuz i didn't have any code before this function. But you can try - maybe it will show something useful for you