Author Archives: dmitriano

How to publish a WordPress post

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Building QT 5.15.0 (everywhere) for Android on Windows

  • Install Android Studio with SDK and NDK API Level 28.
  • Install strawberry-perl- first (before mingw-w64-install.exe) to E:\PFiles
  • Install MinGW with mingw-w64-install.exe online installer. Select POSIX threads in the installer UI combobox, otherwise you will get:
  • Extract the sources from QT archive to E:\Qt\Qt5.15.0 and run the following script in QT root directory containing configure.bat:

Creating Oracle Database in a Cloud

Login to Oracle Cloud console, go to Autonomous Transaction Processing page:


Running a QT app on MacOS

I was able to compile and debug my app on MacOS with QT Creator:

All C++ code compiled successfully, but something went wrong with OpenGLES shaders. It is probably because I included OpenGLES headers from a wrong place.


QT app is deactivated incorrectly on Android 10 in Gesture mode

If I enable Gesture mode on an Android 10 emulator by tapping System->Gestures->System Navigation->Gesture Navigation and then deactivate my app by swiping and reactivate it back, I get the following in the log:

adb logcat | grep "\ Lines"
05-04 21:52:36.389 11794 11939 D Lines   : Squircle::aboutToQuit()
05-04 21:52:36.389 11794 11939 D Lines   : InterstitialAdWrapper clear() called.
05-04 21:52:36.392 11794 11939 D Lines   : InterstitialAdWrapper InterstitialAd destructor called.
05-04 21:52:36.393 11794 11939 D Lines   : Squircle destructor called.
05-04 21:52:36.396 11794 11939 W Lines   : exit app 0
05-04 21:52:37.032 11794 11939 D Lines   : OslSoundPool destructor
05-04 21:52:37.117  2040  2134 W InputDispatcher: channel '8474831 net.geographx.LinesGame/net.geographx.MainActivity (server)' ~ Consumer closed input channel or an error occurred.  events=0x9
05-04 21:52:37.117  2040  2134 E InputDispatcher: channel '8474831 net.geographx.LinesGame/net.geographx.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
05-04 21:52:37.123  2040  3120 I WindowManager: WIN DEATH: Window{8474831 u0 net.geographx.LinesGame/net.geographx.MainActivity}
05-04 21:52:37.123  2040  3120 W InputDispatcher: Attempted to unregister already unregistered input channel '8474831 net.geographx.LinesGame/net.geographx.MainActivity (server)'
05-04 21:52:37.136  2040  3120 W ActivityManager: Scheduling restart of crashed service net.geographx.LinesGame/ in 1000ms
05-04 21:52:37.151  2040  2057 I ActivityManager: Process net.geographx.LinesGame (pid 11794) has died: cch CRE
05-04 21:52:38.034  2040  2057 I ActivityTaskManager: START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=net.geographx.LinesGame/net.geographx.MainActivity bnds=[37,882][238,1191]} from uid 10090
05-04 21:52:38.055  2040  2057 I chatty  : uid=1000(system) Binder:2040_2 identical 8 lines
05-04 21:52:38.099  2040  2072 I ActivityManager: Start proc 12702:net.geographx.LinesGame/u0a134 for activity {net.geographx.LinesGame/net.geographx.MainActivity}
05-04 21:52:38.101 12702 12702 W raphx.LinesGam: Unexpected CPU variant for X86 using defaults: x86
05-04 21:52:38.124 12702 12702 E raphx.LinesGam: Not starting debugger since process cannot load the jdwp agent.
05-04 21:52:38.966  2040  2069 I ActivityTaskManager: Displayed net.geographx.LinesGame/net.geographx.MainActivity: +931ms
05-04 21:52:39.062 12702 12826 D Translation file has been loaded successfully:  "LinesGame_en"
05-04 21:52:39.062 12702 12826 D Lines   : App version:  "2.5.11, #133"
05-04 21:52:39.072 12702 12826 D Lines   : QT/SysInfo: Device Pixel Ratio: 3  Screen DPI:  147.131
05-04 21:52:39.106 12702 12826 D Lines   : InterstitialAdWrapper  valid
05-04 21:52:39.185 12702 12826 D Lines   : qml: Registering adfree
05-04 21:52:39.189  7632  9145 W Finsky  : [672] gcs.d(23): net.geographx.LinesGame: No account found.
05-04 21:52:39.411 12702 12826 D Lines   : qml: adfree Component.onCompleted
05-04 21:52:39.413 12702 12826 D Lines   : InterstitialAdWrapper: calling Java method ' initializeInterstitialAd ' from C++
05-04 21:52:39.413 12702 12826 D Lines   : Starting the application event loop...
05-04 21:52:39.463 12702 12826 D Lines   : onApplicationStateChanged(Qt::ApplicationActive)

Why my QT app crashes at the destructor of std::thread on Android 10 devices?

I did some research on why my QT app crashes at the destructor of std::thread on Android 10 devices at the user side with the following call stack:

#00 /apex/ (abort+160)
#01 /system/lib64/ (abort_message+232)
#02 /system/lib64/ (demangling_terminate_handler()+44)
#03 /system/lib64/ (std::__terminate(void (*)())+12)
#04 /system/lib64/ (std::terminate()+52)
#05 /system/lib64/ (std::__1::thread::~thread()+20)
#06 /apex/ (__cxa_finalize+212)
#07 /apex/ (exit+24)
#08 /data/app/com.domain.myapp-Rs_sm5VrLR1Jj8QW6oYByA==/lib/arm64/

and figured out that its likely because std::thread destructor is being invoked while the thread is still joinable at some point of the application execution (thanks to G. M. on


Shrinking MySQL database

Calculating disk space usage per MySQL DB:

sudo du -h /var/lib/mysql/
932M    /var/lib/mysql/beauty
179M    /var/lib/mysql/slogpost
485M    /var/lib/mysql/omegauto
8.0K    /var/lib/mysql/test
676K    /var/lib/mysql/sys
22G     /var/lib/mysql/bot
79M     /var/lib/mysql/master
11M     /var/lib/mysql/mysql
176K    /var/lib/mysql/phpmyadmin
21M     /var/lib/mysql/shar
127M    /var/lib/mysql/mike
1.1M    /var/lib/mysql/performance_schema
79M     /var/lib/mysql/devnote
12M     /var/lib/mysql/mike1
48K     /var/lib/mysql/game
24G     /var/lib/mysql/

C++ binary serialization speed is comparable with std::memmove

Measuring std::memmove speed

I wrote a simple test that outputs std::memmove speed to the console:

AWT_ATTRIBUTE(size_t, element_count, 1000000);

std::unique_ptr<uint8_t> p_src(new uint8_t[element_count]);
std::memset(p_src.get(), 25u, element_count);

std::unique_ptr<uint8_t> p_dst(new uint8_t[element_count]);

context.out << _T("std::memmove: ");

awl::StopWatch w;

std::memmove(p_dst.get(), p_src.get(), element_count);

ReportSpeed(context, w, element_count);

context.out << std::endl;

And the similar tests for std::memset and std::vector::insert.


A funny example of C++ code that MS can compile :)

In the code below, static_assert operates on the addresses of local variables, but however MS compiles it and the assertion does not fail:

#include <tuple>
#include <string>
struct A
    int a;
    double b;
    std::string c;
void f()
    A a{ 1, 3.0, "abc" };
    constexpr auto t1 = std::tie(a.a, a.b, a.c);
    static_assert(&std::get<0>(t1) == &a.a);

Use the following command to compile this example:

cl /std:c++17 /EHsc a.cpp

How I solved “This version of the application is not configured for billing through Google Play”

I created an unlockable product in Google Play, added billing permission to the manifest:

<uses-permission android:name=""/>

and implemented billing in my application, but when I attempted to purchase the product first time I got error ‘This version of the application is not configured for billing through Google Play‘:

This version of the application is not configured for billing through Google Play