Author Archives: dmitriano

Replace a substring in source file names

For example, the command below

find -name "*android*" -exec rename 's/android/windows/' {} \;

renames the following source files:

androidinappproduct.cpp
androidinappproduct.h
androidinapppurchasebackend.cpp
androidinapppurchasebackend.h
androidinapptransaction.cpp
androidinapptransaction.h
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Compiling QT6.2.2 example with new billing library for Android

To prevent linker errors related to \Qt6.2.2\android\include\QtConcurrent\qtconcurrentrunbase.h

    void run() override
    {
        if (promise.isCanceled()) {
            promise.reportFinished();
            return;
        }
#ifndef QT_NO_EXCEPTIONS
        try {
#endif
            runFunctor();
#ifndef QT_NO_EXCEPTIONS
        } catch (QException &e) {
            promise.reportException(e);
        } catch (...) {
            promise.reportException(QUnhandledException(std::current_exception()));
        }
#endif
        promise.reportFinished();
    }
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Configuring Android NDK version in QT Creator

When I uninstalled old NDK versions including 21.3.6528147, QT Creator displayed this:

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Building QT 6.2.2 for Windows and Android

I downloaded QT 6.2.2, verified its checksum:

certutil -hashfile qt-everywhere-src-6.2.2.zip MD5

Building for Windows with MSVC2019

Configured QT for building in the system Command Prompt (but not in MSVC Developer Command Prompt) as follows:

CALL "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvarsall.bat" amd64
  
set "CMAKE_ROOT=E:\PFiles\cmake-3.21.3-windows-x86_64\bin"
set "NINJA_ROOT=E:\PFiles\ninja-win"
set "PERL_ROOT=E:\PFiles\Strawberry\perl\bin"
   
set PATH=%CMAKE_ROOT%;%PATH%
set PATH=%NINJA_ROOT%;%PATH%
set PATH=%PERL_ROOT%;%PATH%
set PATH=E:\PFiles\Python35;%PATH%
     
rem Check if the tools are in PATH
where perl.exe
where python.exe
where cmake.exe
where ninja.exe
 
set "MY_INSTALL_PATH=E:\Qt\Qt6.2.2\windows"
set CL=/MP
 
configure.bat -prefix %MY_INSTALL_PATH% -DQT_NO_EXCEPTIONS=1 -debug-and-release -force-debug-info -platform win32-msvc -opensource -confirm-license ^
-opengl es2 -I "C:\Program Files\OpenSSL\include" -L "C:\Program Files\OpenSSL\lib"
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I have MacBook

And it is even Pro:

System Version: macOS 11.6 (20G165)
Kernel Version: Darwin 20.6.0

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“Server certificate verification failed” error with command line Git client

Some guy described the same situation about 10 years ago on stackoverflow.com and there was another discussion about 7 years ago.

First I did:

GIT_CURL_VERBOSE=1 git clone https://git.developernote.com/examples.git
Cloning into 'examples'...
* Couldn't find host git.developernote.com in the .netrc file; using defaults
*   Trying 139.162.243.103...
* TCP_NODELAY set
* Connected to git.developernote.com (139.162.243.103) port 443 (#0)
* found 129 certificates in /etc/ssl/certs/ca-certificates.crt
* found 387 certificates in /etc/ssl/certs
* ALPN, offering http/1.1
* SSL connection using TLS1.2 / ECDHE_RSA_AES_256_GCM_SHA384
* server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
* stopped the pause stream!
* Closing connection 0
fatal: unable to access 'https://git.developernote.com/examples.git/': server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
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How to backup entire disk on MacOS

Open Disk Utility, select View->Show All Devices, select the disk and then Image from … :

To restore the disk from backup create a boot USB flash, boot from it and use Recovery option.

Periodically get ‘device not responding’ error on my HiveOS rig

Once a 2 or 3 minutes I get the following error in the miner log:

grep -i error /var/log/miner/gminer/gminer.log
Error on GPU6: Device not responding, check overclocking settings

and on the following message on the miner screen:

miner
GPU6: DAG has been damaged, check overclocking settings
Miner terminated, watchdog will restart process after 10 seconds

GPU temperature is about 50-60°C, but looks like the memory chips overheat, because there was NVidia error:

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Writing market data to SQLite database

SQLite utilizes up to 90% of the my SSD disk when SHIB coin riches its local peaks with more than 10.000 – 18.000 trades/min that is 166 – 300 trades/second. My C++ app inserts 64-bit values to tables like this:

CREATE TABLE trades (time INT PRIMARY KEY NOT NULL, price REAL, volume REAL) WITHOUT ROWID;

so it is only 3984 – 7200 bytes/second. Totally across all markets there can be about 30.000 trades/min that is 500 trades/second and only 12.000 bytes/second and it is enough to slow down my SQLite database.

I use WAL with 4GB cache:

PRAGMA journal_mode = WAL;
PRAGMA cache_size = -4 * 1024 * 1024;

and do all the inserts in a transaction once a 5 seconds into 500+ tables (a separate table for each market) with a prepared statement.

See the screenshots of my app below:

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Building QT 6.2 for Android on Windows

First I built QT 6.2 for Windows then I installed JDK8, CMake 3.21.3 and configured QT as follows:

set "CMAKE_ROOT=E:\PFiles\cmake-3.21.3-windows-x86_64\bin"
set "NINJA_ROOT=E:\PFiles\ninja-win"
set "JDK_ROOT=C:\Program Files\Java\jdk1.8.0_301\bin"
set "MINGW_ROOT=E:\PFiles\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin"
set "PERL_ROOT=E:\PFiles\Strawberry\perl\bin"
 
set PATH=C:\WINDOWS\system32;C:\WINDOWS
set PATH=%CMAKE_ROOT%;%PATH%
set PATH=%NINJA_ROOT%;%PATH%
set PATH=%JDK_ROOT%;%PATH%
set PATH=%MINGW_ROOT%;%PATH%
set PATH=%PERL_ROOT%;%PATH%
set PATH=E:\PFiles\Python35;%PATH%
   
rem Check if the tools are in PATH
where gcc
where mingw32-make.exe
where perl.exe
where javac.exe
where python.exe
where cmake.exe
where ninja.exe

set "ANDROID_SDK_ROOT=C:\Users\D-Ef\AppData\Local\Android\Sdk"
set "ANDROID_NDK_PATH=C:\Users\D-Ef\AppData\Local\Android\Sdk\ndk\21.3.6528147"
rem See qtbase\mkspecs\android-clang\qmake.conf
set "ANDROID_NDK_PLATFORM=android-23"
rem see %ANDROID_SDK_ROOT%\build-tools folder
set "ANDROID_BUILD_TOOLS_REVISION=29.0.2"
 
set MY_INSTALL_PATH=E:\Qt\Qt6.2\android
set QT_HOST_PATH=E:\Qt\Qt6.2\windows

configure.bat -platform android-clang -prefix %MY_INSTALL_PATH% -android-sdk %ANDROID_SDK_ROOT% -android-ndk %ANDROID_NDK_PATH% -qt-host-path %QT_HOST_PATH% -android-abis x86_64 ^
  -DQT_NO_EXCEPTIONS=1 -release -force-debug-info -opensource -confirm-license
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