No qDebug()<<"Output"; on android

[SeDi]

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Update: this problem might very well be linked to that pointed out here: https://forum.qt.io/topic/157825/waiting-for-the-debugger-to-attach
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Writing for Android I don't see any qDebug()<<"Output"; whatsoever. Only after I've ended the program (e.g. from the phone by its back button), I see:

15:05:59: 

"org.qtproject.example.myTestProject" died.

The problem occurs in new projects and across different Qt Versions.
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Update: It does, although, not appear on another person's Android device (Samsung Tablet SM-T830 with Android 10).
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I don't see anything in "Application Output" pane (except the above, after program ends).

Debug output when running on Windows is fine, however. There everything works like expected.

The code I use is simply:

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QDebug>

int main(int argc, char *argv[])
{
// [automatically generated QML stuff omitted here] 
    engine.load(url);
    for (int i=0; i<100;i++) qDebug()<<"###############################!!!!!!!!!!!!!###############";
    // for (int i=0; i<100;i++) std::printf("###############################!!!!!!!!!!!!!###############");
    return app.exec();
}

I've tried:

• making sure I use DEBUG configuration^^
• restarting Windows machine and phone
• adding android:debuggable="true" to <application...> tag in AndroidManifext.xml
• toggling Edit|Preferences|Debugger|General|Force Logging To Console
• toggling Edit|Preferences|Build&Run|Application Output|Merge stderr and stdout
• starting new projects in different Qt Versions: 5.15.2, 6.5.1 and 6.7.2, with compat option(qmake) and without(cmake)
• using std::fprintf(stderr, "output");
• using std::cerr << QString("Output").toStdString() << std::endl;
• setting qputenv("QT_ASSUME_STDERR_HAS_CONSOLE", "1");
• uninstalling app before deploying again
• removing build folders

In the the (otherwise very vivid and cluttered) adb logcat the output does appear as

07-20 14:26:46.551 17346 17367 D libtestLogCompat_arm64-v8a.so: ###############################!!!!!!!!!!!!!###############
07-20 14:26:46.552 17346 17367 I chatty  : uid=10169(org.qtproject.example.testLogCompat) qtMainLoopThrea identical 98 lines
07-20 14:26:46.552 17346 17367 D libtestLogCompat_arm64-v8a.so: ###############################!!!!!!!!!!!!!###############

Would be fine - but it's buried under thousands of other log lines.

The same applies for console.log("output") from QML
N.B.: I couldn't find output to std::printf anywhere.

Win 10 machine, Qt Creator 13.0.2, deploying to a Nokia 8 (TA-1012) with Android 9, several Qt versions.

[maris]

I don't understand why but qWarning() works OK ;)

other solution, use spdlog

#include "spdlog/sinks/android_sink.h"

    // auto file_sink = std::make_shared<spdlog::sinks::basic_file_sink_mt>("logs/multisink.txt", true);
    // file_sink->set_level(spdlog::level::trace);
    auto android_sink = std::make_shared<spdlog::sinks::android_sink_mt>("ssss", false);
    android_sink->set_pattern("[multi_sink_example] [%^%l%$] %v"); // to dziala jak jest "false" powyżej

    spdlog::set_default_logger(std::make_shared<spdlog::logger>("multi_sink",
        spdlog::sinks_init_list({android_sink
                                // ,file_sink
                                }))
    );

 spdlog::info("###############################!!!!!!!!!!!!!###############");