Issue with QProcess and rundll32

Cobra91151

Hello!

I want to use the QProcess to remove some installed programs. The problem is with rundll32.exe.

For example, I want to uninstall this one:
C:\Windows\SysWOW64\RunDll32.EXE C:\Program Files\NVIDIA Corporation\Installer2\InstallerCore\NVI2.DLL,UninstallPackage CUDADevelopment_11.8

Code:

QProcess *appProcess = new QProcess(this);
connect(appProcess, &QProcess::started, this, [this, appProcess]() {
        qDebug() << appProcess->errorString();
 });
connect(appProcess, qOverload<int>(&QProcess::finished), this, [this, appProcess]() {
        qDebug() << "Error: " << appProcess->errorString();
       appProcess->close();
       appProcess->removeLater();
       emit finished();
});
QStringList runDll32Path = item->text(column).split(".exe", QString::KeepEmptyParts, Qt::CaseInsensitive);
QString appPath = runDll32Path.first().append(".exe");
QString appParameter = runDll32Path.last().simplified();
qDebug() << "appPath: " << appPath;
QStringList appArgs = appParameter.split(".dll", QString::KeepEmptyParts, Qt::CaseInsensitive);
QString arg1 = appArgs.first().append(".dll");
QString arg2 = appArgs.last();
appProcess->start(appPath, QStringList() << QString("\"%1\"%2").arg(arg1, arg2));

It reports:

appPath:  "C:\\Windows\\SysWOW64\\RunDll32.exe"
Args:  "\"C:\\Program Files\\NVIDIA Corporation\\Installer2\\InstallerCore\\NVI2.dll\",UninstallPackage CUDADevelopment_11.8"
"Unknown error"
Error:  "Unknown error"

But the process immediatly closes and does not display any dialog.
I have tried it with ShellExecute and it works well but it fails with QProcess.
I want to use it with QProcess to check if the process is still running or not. Any ideas? Thank you.

JonB

@Cobra91151
If it were me I would probably try using void QProcess::setNativeArguments(const QString &arguments) now to be sure what I was passing. By-passing Qt's quoting of your argument(s).

JonB

@Cobra91151
I am not convinced about your quoting of the argument, and tbh I'm note sure exactly what rundll32 will be requiring there. I would try removing the surrounding "s you have put in QString("\"%1\"%2").arg(arg1, arg2).

C:\Windows\SysWOW64\RunDll32.EXE C:\Program Files\NVIDIA Corporation\Installer2\InstallerCore\NVI2.DLL,UninstallPackage CUDADevelopment_11.8

Are you saying that if you type this in verbatim in a Command Prompt it would work exactly as shown?

Cobra91151

@JonB
Hello!

The quotes must be there for argument otherwise it will not start. Using CMD, ShellExecute or Run app it starts.

Here is an example:
rundll32.exe "C:\\Program Files\\Synaptics\\SynTP\\SynISDLL.dll",standAloneUninstall

Here is the screenshot:

It fails with QProcess for some reason.

JonB

@Cobra91151
If it were me I would probably try using void QProcess::setNativeArguments(const QString &arguments) now to be sure what I was passing. By-passing Qt's quoting of your argument(s).

Cobra91151

@JonB

Ok. I will try it and reply later. Thank you.

Cobra91151

@JonB

Yes, it works well. The issue is resolved. Thank you for your help.