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I'm using Qt and want to check if any Wayland session is running.

For now I have this just for test code, that works as expected:

QProcess process;
process.setProgram("bash");
process.setArguments({"-c", "loginctl list-sessions --no-legend | awk '{print $1}'"});
process.start();
process.waitForFinished();
const QByteArrayList sessionsList = process.readAll().split('\n');

foreach (const QByteArray &sessionID, sessionsList) {
    if (sessionID.isEmpty())
        continue;
    process.setArguments({"-c", "loginctl show-session " + sessionID});
    process.start();
    process.waitForFinished();
    if (process.readAll().contains("Type=wayland"))
        qDebug() << "At least one Wayland session is running";
}

Is it possible to get rid of QProcess and use Linux C++ API?

Shatur95
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1 Answers1

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You can try to connect to Wayland. If you can connect to a Wayland composer it is running otherwise is not running or someone haven't set the environment variables correctly and not used the default name.

#include <wayland/wayland-client-core.h>

bool isWaylandRunning(){
    auto display = wl_display_connect(nullptr);
    if (display){
        wl_display_disconnect(display);
        return true;
    } else {
        return false;
    }
}
user6556709
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  • Great idea! But is it possible to somehow use the loginctl API? Unfortunately, the method proposed by you requires installing Wayland into the system, and in my program I need to interrupt work if at least one Wayland session is running :( – Shatur95 May 03 '19 at 18:05
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    Logind has a dbus interface on the system bus at "/org/freedesktop/login1/". With the service "org.freedesktop.login1.Manager" you can call "ListSessions" to get the sessions. Each session has "org.freedesktop.login1.Session" service which has a "Type" property. – user6556709 May 03 '19 at 18:27
  • Just what I need, thank you! I suggest to add this to answer. – Shatur95 May 03 '19 at 20:49