Author Archives: dmitriano

Key knowledge about forwarding references in C++

The compiler deduces U as std::string& or as std::string depending on value category of the argument:

template <class U>
void f(U&& s)
{
    static_assert(std::is_same_v<U, const std::string&>);

    std::cout << std::forward<U>(s) << std::endl;
}

int main()
{
    const std::string& s = "abc";

    f(s);

    return 0;
}
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Creating Windows Application Icon on Ubuntu 22.04

Install magick tool:

sudo apt update
sudo apt install imagemagick

Copy *.png files to a folder, for example:

win16x16.png
win32x32.png
win48x48.png
win64x64.png

and run the following command:

convert *.png winapp.ico

QDebug can’t be used from a destructor of a static object

We can’t do this in QT:

class Global
{
public:

    ~Global()
    {
        qDebug() << "Global destructor.";
    }
};

Global g;
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QML Application Style

There was qtquickcontrols2.conf in the root directory of my app sources with the following content:

; This file can be edited to change the style of the application
; See Styling Qt Quick Controls 2 in the documentation for details:
; https://doc.qt.io/qt-6/qtquickcontrols2-styles.html

[Controls]
;Style=Default
;Style=Universal
;Style=Material
Style=Fusion
;Style=iOS

[Universal]
Theme=Light
Accent=Steel

[Material]
;Theme=Light
Theme=Dark
;Accent=BlueGrey
;Primary=BlueGray
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QT6 multimedia module crashes on iOS

After several hours of playing sounds my iOS app crashes and the QT Creator displays the following stack trace:

1 caulk::thread::join() (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/caulk.framework/caulk 0x7fff49a06293
2 std::__shared_ptr_emplace<AURemoteIO::IOThread, std::allocator<AURemoteIO::IOThread>>::__on_zero_shared() (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff438a7469
3 AURemoteIO::Stop() (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff438a58d3
4 ausdk::AUMethodStop(void *) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff438f3529
5 QDarwinAudioSink::audioDeviceStop() qdarwinaudiosink.mm 619 0x10ffa7afd
6 QDarwinAudioSink::audioDeviceIdle() qdarwinaudiosink.mm 629 0x10ffa7b68
7 QDarwinAudioSink::renderCallback(void *, unsigned int *, AudioTimeStamp const *, unsigned int, unsigned int, AudioBufferList *) qdarwinaudiosink.mm 446 0x10ffa7ab7
8 ausdk::AUInputElement::PullInput(unsigned int&, AudioTimeStamp const&, unsigned int, unsigned int) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff438f12d2
9 AUInputFormatConverter2::InputProc(OpaqueAudioConverter *, unsigned int *, AudioBufferList *, AudioStreamPacketDescription * *, void *) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff4382cf27
10 acv1::AudioConverterChain::CallInputProc(unsigned int) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AudioToolboxCore.framework/AudioToolboxCore 0x7fff30323840
11 acv1::AudioConverterChain::FillBufferFromInputProc(unsigned int *, CADeprecated::CABufferList *) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AudioToolboxCore.framework/AudioToolboxCore 0x7fff3032467f
12 acv1::BufferedAudioConverter::GetInputBytes(unsigned int, unsigned int&, CADeprecated::CABufferList const *&) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AudioToolboxCore.framework/AudioToolboxCore 0x7fff3045c7bd
13 acv1::CBRConverter::RenderOutput(CADeprecated::CABufferList *, unsigned int, unsigned int&, AudioStreamPacketDescription *) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AudioToolboxCore.framework/AudioToolboxCore 0x7fff303091bc
14 acv1::BufferedAudioConverter::FillBuffer(unsigned int&, AudioBufferList&, AudioStreamPacketDescription *) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AudioToolboxCore.framework/AudioToolboxCore 0x7fff3045c589
15 acv1::AudioConverterChain::RenderOutput(CADeprecated::CABufferList *, unsigned int, unsigned int&, AudioStreamPacketDescription *) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AudioToolboxCore.framework/AudioToolboxCore 0x7fff303235bb
16 acv1::BufferedAudioConverter::FillBuffer(unsigned int&, AudioBufferList&, AudioStreamPacketDescription *) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AudioToolboxCore.framework/AudioToolboxCore 0x7fff3045c589
17 acv1::_AudioConverterFillComplexBuffer(OpaqueAudioConverter *, int ( *)(OpaqueAudioConverter *, unsigned int *, AudioBufferList *, AudioStreamPacketDescription * *, void *), void *, unsigned int *, AudioBufferList *, AudioStreamPacketDescription *, AudioStreamPacketDependencyInfo *) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AudioToolboxCore.framework/AudioToolboxCore 0x7fff30491df6
18 AudioConverterFillComplexBuffer (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AudioToolboxCore.framework/AudioToolboxCore 0x7fff303a3680
19 AUConverterBase::RenderBus(unsigned int&, AudioTimeStamp const&, unsigned int, unsigned int) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff4382b617
20 AURemoteIO::RenderBus(unsigned int&, AudioTimeStamp const&, unsigned int, unsigned int) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff438a4317
21 ausdk::AUBase::DoRender(unsigned int&, AudioTimeStamp const&, unsigned int, unsigned int, AudioBufferList&) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff438f06a9
22 AURemoteIO::PerformIO(unsigned int, unsigned int, unsigned int, AudioTimeStamp const&, AudioTimeStamp const&, AudioBufferList const *, AudioBufferList *, unsigned int&) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff438af7df
23 _XPerformIO (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff438e9817
24 mshMIGPerform (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libAudioToolboxUtility.dylib 0x7fff2e30936a
25 MSHMIGDispatchMessage (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libAudioToolboxUtility.dylib 0x7fff2e309759
26 void * caulk::thread_proxy<std::tuple<caulk::thread::attributes, AURemoteIO::IOThread::IOThread(AURemoteIO&, caulk::thread::attributes const&, caulk::mach::os_workgroup const&)::'lambda'(), std::tuple<>>>(void *) (x86_64) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AudioToolbox.framework/libEmbeddedSystemAUs.dylib 0x7fff438a7200
27 _pthread_start (x86_64) /usr/lib/system/libsystem_pthread.dylib 0x7fff6da2b8fc
28 thread_start (x86_64) /usr/lib/system/libsystem_pthread.dylib 0x7fff6da27443
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What is the difference between -nativeScale and -scale on UIScreen in iOS

Found the answer on stackoverflow.com and installed iPhone 6 Plus simulator:

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Building QT6.4 on Windows for Android with OpenSSL and clang 14

Installed latest NDK:

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Building QT6.4 on Windows for Android with OpenSSL and clang 12

My mistake was that while building QT6.4 on Windows for Android I tried to set OPENSSL_ROOT_DIR as an environment variable that doesn’t take an effect. Now I set it as an argument:

C:\dev\build\qta
  
set "CMAKE_ROOT=C:\dev\PFiles\cmake-3.24.2-windows-x86_64\bin"
set "NINJA_ROOT=C:\dev\PFiles\ninja-win"
set "PERL_ROOT=C:\dev\PFiles\Strawberry\perl\bin"
set "MINGW_ROOT=C:\dev\PFiles\x86_64-12.2.0-release-win32-seh-rt_v10-rev0\mingw64\bin"
set "PYTHON_ROOT=C:\dev\PFiles\Python35"
set "JDK_ROOT=C:\dev\libs\jdk-19\bin"
          
set PATH=C:\WINDOWS\system32;C:\WINDOWS
set PATH=%CMAKE_ROOT%;%PATH%
set PATH=%NINJA_ROOT%;%PATH%
set PATH=%MINGW_ROOT%;%PATH%
set PATH=%PERL_ROOT%;%PATH%
set PATH=%PYTHON_ROOT%;%PATH%
set PATH=%JDK_ROOT%;%PATH%  

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My attempt to build OpenSSL for Android on Windows

I tried to build OpenSSL for Android with the following commands in Windows Command Prompt:

cd C:\dev\repos\openssl-1.1.1r

set MY_NDK_DIR=C:\Users\dmitr\AppData\Local\Android\Sdk\ndk\23.1.7779620

set MY_CLANG_DIR=%MY_NDK_DIR%\toolchains\llvm\prebuilt\windows-x86_64\bin
set MY_CMAKE=%MY_NDK_DIR%\prebuilt\windows-x86_64\bin\make.exe
set MY_PERL_DIR=C:\dev\PFiles\Strawberry\perl\bin

set PATH=%MY_CLANG_DIR%;%MY_PERL_DIR%;%PATH%

set "MY_ANDROID_BUILD_ABI=x86_64"
rem set "MY_ANDROID_BUILD_ABI=x86"
rem set "MY_ANDROID_BUILD_ABI=arm64"
rem set "MY_ANDROID_BUILD_ABI=arm"

set MY_INSTALL_ROOT_DIR=C:/dev/libs/OpenSSL-android
set MY_INSTALL_DIR=%MY_INSTALL_ROOT_DIR%/%MY_ANDROID_BUILD_ABI%

set ANDROID_NDK_HOME=%MY_NDK_DIR%

# Set compiler clang, instead of gcc by default
set CC=clang

perl Configure android-%MY_ANDROID_BUILD_ABI% -D__ANDROID_API__=23 --prefix="%MY_INSTALL_DIR%" --openssldir="%MY_INSTALL_DIR%" no-shared
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Building QT6.4 on Windows for Android

I installed Android Studio and pressed two buttons in QT Creator:

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