I’m currently logged onto a machine and my current problem involves a custom build step that has trouble copying a .dll to the Bin directory because Windows says it cannot access the file because it’s currently being used by another process.
I’m able to reproduce this on several other projects. The sequence of events is that I build a release successfully, do some test, checkout another SHA when doing a git bisect, and attempt to build a release from that SHA without doing a git clean -xfd (intentionally, because I’m trying to cache as much reusable data as possible). The weird thing is that I tried to use Process Explorer (procexp) and tasklist /m <locked_dll.dll> to search for whatever is holding onto this dll, and am unable to find anything holding onto the dll. I’m on a non-admin account, and I’m not sure if that is causing Windows to hide certain processes from me. Rebooting the machine helps, but that’s not an acceptable solution since I’m trying to automate things. I’m able to delete the .dll, and when I try to build the project in VS, it’ll complain that it still can’t access the dll when trying to copy it over to the Bin folder. Any ideas? I’m going to keep researching the issue, but as of right now, I’m sort of stumped.
EDIT:
This seems to be a duplicate question (Error: Cannot access file bin/Debug/... because it is being used by another process), but I'll leave this open to see if anyone has found anything new related to the topic.
I've seen this problem in VS 2010 with a large .Net solution with multiple projects in it. Every case I've seen so far pertains to have one project with dependency DLLs that another project also uses, and that other project also uses the first project as a reference, and also uses the same dependency DLLs that happen to be a different version from the first project.
To describe it a different way:
Project A depends on v1 of DLL A
Project B depends on project A and v2 of DLL A
Both project A and B are in the same solution
The solution is to use the same version of DLL A. I usually run into this when upgrading to a new version of SQLite, and I forget to update the dependency in all of my projects.
After talking with a few coworkers, I found the solution to my problem. procexp and tasklist did not see which process was locking the dll because there was no process locking the dll on that particular machine.
I have a hardware configuration where machine A (a host PC) is connected to machine B (acts as a client that retrieves instructions from machine A) using a network switch. machine B runs the same binaries that link to the same dll's. Thus, obviously, running procexp or tasklist on machine A will not see anything locking the dll's because machine B is the culprit.
Related
for a self-built installer I need a way to execute code after closing of an application itself.
Application structure
Main application: The installer is started from it when needed, it closes itself in the process.
Installer: This is also located in the folder of the main application and therefore also accesses all dll files. When an update is available, a zip file is first downloaded and then unpacked into the temp folder. Afterwards, all files are moved from there to the shared application directory.
The problem
The problem is that the updater can only update a few dll files at runtime that are not used by itself, because some are write-protected due to the installer's access.
A solution
Moving the files from the temp folder to the shared application folder must happen after closing the installer. But I don't know how to realize that.
Thanks a lot!
If your problem are the DLLs shared by the installer and main application, then you can do this: Before you run the installer, your main application can copy all the needed DLLs and the installer EXE from your main application folder to a temporary folder and run it from there. Your installer must then only wait until the main application gets closed and then replace all its files in the main folder. And once your update is finished, delete this temporary copy of the installer with its DLLs.
Note that if you want to overwrite files in Program Files folder, your installer will have to be run with elevated privileges. Google for "runas" command... you will need it when starting your installer with QProcess.
But there may be also other problems. If your first installation was with normal installer, it typically creates some entries in registry and also generates list of files for later uninstall. And if your new versions will contain different files than originally installed version, then your subsequent uninstall may malfunction or may leave some files existing on users' computers. And you certainly do not want this.
And yet another potential problem. You may have running several instances of your application. In that case quitting one instance will still leave the other instances running and hence their files will not be replacable by the installer - it will fail.
So as you can see, these are quire serious aspects to take into account.
How I do it in my software and I suggest you try it too? I prepare one installer file (.exe) with InnoSetup (freeware!). This can be used for first installation as well as for automatic updates. Then if I create a new version and put it on the server, the running main application detects it, downloads the new installer and runs this installer (of course it asks the user if it should proceed). The installer then asks for elevated privileges, asks to close the running application (it usually is closed automatically when starting the installer) and overwrites the existing installation. All this is standard functionality built in the installer created by InnoSetup. And correctly updates the uninstall instructions... It took me several days to set up everything to my needs but it works well. The only "drawback" is that it is not completely silent, it shows some dialogs. But this is no real issue for me. Maybe it is better for the users to see what is happening on their computer...
Your question implies Windows. I'll make a suggestion from a Win32 perspective.
In our application, we have a similar issue. Periodically, our application downloads an update executable into a temp folder and then launches it. When the update EXE runs, it makes sure the main application has exited, unpacks the files into the application's installation folder, and then starts the application back up again. It's actually more complicated than that, as it really copies the new files into a different install folder, but I'll save those details unless you really need it.
The problem is that the updater can only update a few dll files at runtime that are not used by itself, because some are write-protected due to the installer's access.
This is the core of your issue. My advice is to have the Installer EXE statically linked to both the VC runtime and the other code its sharing with the application. That is, no DLL dependencies all. If you really need to share code between the installer and the application, but still want the application to use a DLL, you can do this. Have the shared code built as both a DLL (with a stub lib) and also built as a full LIB. May require some minor refactoring to your build or redundantly build the same source files. The Installer code links with the full LIB. The application code links with the stub LIB for the DLL like it does now.
If you are just looking for a way to launch the process, the API you want is CreateProcess.
Also, have you looked at the open source options like Omaha - which is what Google Chrome has used for silent updates?
Moving the files from the temp folder to the shared application folder must happen after closing the installer. But I don't know how to realize that.
The "Windows way" would be to use PendingFileRenameOperations as described in this blog-post and have Windows do the move during the next startup. Of course that implies one more of the annoying "Please reboot to finish the installation" messages.
I'm currently working on a GUI app that is supposed to decrypt some data and print it on the screen, on Windows and Qt (C++) based. The code works fine and I now have to distribute it.
However, the format of the data to decipher can (and will) evolve, and is described on headers (.h) and sources (.c). Therefore, when this happens, I just have to change these files to the last version, the compilation goes fine and the program runs smoothly. It's a simple drag&drop of the new files in my source folder, really.
I am aware of how to deploy a .exe (with the correct dll and so forth), but I don't think it would work in this case. I briefly looked at how to create installers but i'm not sure that this is the right way to handle the situation (http://doc.qt.io/qtinstallerframework/ifw-creating-installers.html).
How could I distribute this code so that people that want to use it can just change the sources, run a script, and the .exe is generated, even with a computer that does not have Qt ? (but probably mingw32 and only on Windows)
Thanks in advance for your help !
From my understanding, you should include dll's and if the format of the data changes, you can just update and maintain your dll's.
Build your project in release mode and then use QTWinDeploy to finalize the build of the project with all the dependencys the projects require for users without QT.
This is how I maintain and distribute a project similar to yours.
Otherwise, I would recommend looking at self-updating programs.
I'm having a difficult problem to solve. I'm having two Qt-based applications, first one is in the main folder and the second one is located in it's subdirectory (yes, I'm forced to have it this way). The issue I'm facing is that I have to deliver 5 exact the same DLL's files for each application. I wouldn't have problem with that, if they wouldn't weight so much (10 DLL files = 60~ MB). Which is, definately too much.
On my debug build I am able to set the PATH variable within Visual Studio settings, and I will be not able to do so on production machines.
Is there any way I could set one of those application to rely on DLL files located in subdirectory?
I don't know what kind of an installer you're using, but the dlls should be stored only once in the archive, and the files should be hard linked on installation. So it's a non-issue unless your installer is broken or the install script is.
You have your GUI application, filling all the list of requirements that the client has requested. All work is set and done, finally it is time to deploy. You promise to your client it won't take long now...
Except... Except that I have been postponing the deploy for the last two weeks trying to accomplish this task, but I couldn't imagine the nightmare it would be to finish the project and release it for the client.
So I have gone through the poor Qt 5.7 Documentation on how to deploy the project, I have tried to build Qt statically with no success, I am trying to dynamically link it but with no success.
I would appreciate the help from some experienced user who could help me step-by-step to either build it statically or dynamically and be able to release the project.
Basically, for my static build, I have tried the following:
./configure -static -prefix=PATH
make
make install
Then I believe I should have a *.a file from here somewhere, but it doesn't happen so far. It takes a hell of a time, but no output can be observed in the working directory.
For dynamically linking, I have gone through ldd appname, copied all the listed libraries to a folder, but now I am running through the issue of building it dynamically with the entire list of dependencies and having them visible for my project (using qtcreator here too, which is making if even more messy for me).
So, as for now, I am lost and running out of time in order to achieve what was supposed to be not such a complicated task. I accept any recommendation that allows me to distribute the project to the client, without having to worry if the client has all dependencies installed.
I developed a Qt application in MacBook (El-Capitan 10.11.2) and it is ready now to be released.
What i want now, is to create the standalone executable file for both Mac and Windows OS.
But I don't know how !
I found this link but I am unable to follow it is guidance, it looks different from what my system is showing me.
If you have any idea, please help me.
Thank you
Well, to compile an application for windows, you will need a windows machine (or at least a virtual machine). You can't compile for windows on mac.
Regarding the "standalone": The easy way is to deploy your application together with all the required dlls/frameworks and ship them as one "package". To to this, there are the tools windeployqt and macdeployqt. However, those will not be "single file" applications, but rather a collection of files.
If you want to have one single file, you will have to build Qt statically! You can to this, but you will have to do it on your own. And if you do, please notice that the LGPL-license (the one for the free version of Qt) requires you to make the source-code of your program public! That's not the case if you just link to the dynamic libraries.
EDIT:
Deployment
Deployment can be really hard, because you have to do it differently for each platform. Most times you will have 3 steps
Dependency resolving: In this step, you collect all the exectuables/lirabries/translations/... your application requires and collect them somewhere they can find each other. For windows and mac, this can be done using the tools I mentioned above.
Installation: Here you will have to create some kind of "installer". The easiest way is to create a zip-file that contains everyhing you need. But if you want to have a "nice" installation, you will have to create proper "installers" for each platform. (One of many possibilities is the Qt Installer Framework. Best thing about it: It's cross platform.)
Distribution: Distribution is how to get your program to the user. On Mac, you will have the App-Store, for windows you don't. Best way is to provide the download on a website created for this (like sourceforge, github, ...)
I can help you with the first step, but for the second step you will have to research the possibilities and decide for a way to do it.
Dependencies
Resolving the dependencies can be done by either building Qt statically (this way you will have only one single file, but gain additional work because you will have to compile Qt) or using the dynamic build. For the dynamic build, Qt will help you to resolve the dependencies:
macdeployqt is rather easy to use. Compile your app in release mode and call <qt_install_dir>/bin/macdeployqt <path_to_your_bundle>/<bundle>.app. After thats done, all Qt libraries are stored inside the <bundle>.app folder.
For windeployqt is basically the same: <qt_install_dir>\bin\windeployqt --release <path_to_your_build>\<application>.exe. All dependencies will be inside the build folder. (Hint: copy the <application>.exe in an empty directoy and run windeployqt on that path instead. This way you get rid of all the build-files).
Regarding the static build: Just google it, you will find hundreds of explanations for any platform. But unless you have no other choice but to use one single file (for whatever reason) it would recommend you to use dynamic builds. And regarding the user experience: On mac, they won't notice a difference, since in both cases everything will be hidden inside the app bundle. On windows, it's normal to have multiple files, so no one will bother. (And if you create an installer for windows, just make sure to add a desktop shortcut. This way the user will to have "a single file" to click.)