Using QProcess to call an external program, with arguments

Question

I have a exe folder located in one folder, and then all of my config files in another. In order to run the program:

I need to direct the terminal to the config file folder
Then run the exe folder, with arguments.

Shown below, I have this working correctly using system calls, but I need a system agnostic way of doing this.

void MainWindow::on_pushButton_clicked()
{
    std::system("cd Path_To_ConfigFolder & Absolute_Path_To_Exe RunFile.txt > logfile.txt");
}

The above works great. Although it only works on Windows.. so I did some research on using QProcess to create a more system agnostic way.. and no matter what I try I can't seem to get this to work. See below:

void MainWindow::on_pushButton_clicked()
{
    QProcess p;
    QStringList params;
    p.setWorkingDirectory("Path_To_ConfigFolder");
    params << " RunFile.txt > logfile.txt";
    p.start("Absolute_Path_To_Exe", params);
    p.waitForFinished(-1);
}

Note: For the above example (using QProcess), I am \\ for all my paths, and all my paths are correct.

What am I doing wrong here?

You need to check all possible errors of course. See https://stackoverflow.com/questions/60969455/how-to-run-an-external-application-from-qt-program/60973204#60973204 — Vladimir Bershov, Sep 25 '20 at 15:21

Swift - Friday Pie · Accepted Answer · 2020-09-25T15:34:10.647

2

Name of executable would be starting with ".\" if it is in local folder to be system-agnostic. Linux shell and PowerShell require that.

">" - output redirection isn't an argument of process, that won't work. You have to redirect output channel to your or a secondary process.

p.setStandardOutputFile("log_file.txt")

edited Sep 25 '20 at 15:34

answered Sep 25 '20 at 15:27

Swift - Friday Pie

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Thanks for your help @Swift . How do I direct to the output file inside of p.start()? – Tyler Beauregard Sep 25 '20 at 15:40
1

@TBCoder92 Have a look at [`QProcess::setStandardOutputFile`](https://doc.qt.io/qt-5/qprocess.html#setStandardOutputFile). – G.M. Sep 25 '20 at 15:47
Placed `p.setStandardOutputFile(AbsPathToLogFile.txt)` above `p.start()` and removed space before `RunFile.txt` . Doing these all worked, thanks for the help! – Tyler Beauregard Sep 25 '20 at 16:09

Using QProcess to call an external program, with arguments

1 Answers1