Question about QProcess

I tried to use QProcess to run program B from program A. I want to know when program B finished so the program A could do something else.

In CentOS system, both program A and B are GUI programs:

in mainwindow.h:

private:
QProcess proc;
private slots:
void procFinished(int exitCode, QProcess::ExitStatus exitStatus);
void on_execBPushButton_clicked();

in mainwindow.cpp

void MainWindow::on_execBPushButton_clicked()
{
QStringList args;
args << "1";
connect(&proc, SIGNAL(finished(int, QProcess::ExitStatus)), this, SLOT(procFinished(int, QProcess::ExitStatus)));
proc.start("<path>/B", args);
proc.waitForFinished();
}

void MainWindow::procFinished(int exitCode, QProcess::ExitStatus exitStatus)
{
cout << "procFinished() is called" << endl;
}

These are the code to handle the QProcess. I found if I use proc.waitForFinish(), the program A could not refresh the GUI. I know that because after B is launched, I drag the B across A and leave the "trace" on A forever. If I delete this waitForFinsihed(), program A and B both are refreshing when they need.

Also, the "procFinished() is called" did not display after program B is terminated. Instead, the "... is called" display when program A is terminated. So, could anyone tell me what I did wrong?

Thanks in advance.

Don't call the function waitForFinished() and your main program won't stop and wait for the other program to finish.

You are already connecting to the QProcess:finished() signal, so you will get notified when the process exits. As ChrisW67 says, no need to call QProcess::waitForFinished(). If there are things that Program A should not do while Program B is executing (like allow the "execBPushButton" to be clicked again), then you should disable it in the on_execBPushButton_clicked() slot and enable it again in the procFinished() slot.