Category Archives: C++

Detecting memory leaks of C++ application in Ubuntu

First, I tried Valgrind tool using the following command:

valgrind --tool=memcheck --leak-check=yes ./app

With some large QT application started for some short period I got the following output:

==7090== HEAP SUMMARY:
==7090==     in use at exit: 5,623,365 bytes in 36,268 blocks
==7090==   total heap usage: 32,454,680 allocs, 32,418,412 frees, 12,822,939,874 bytes allocated
…………………………..
==7090== LEAK SUMMARY:
==7090== definitely lost: 20,163 bytes in 74 blocks
==7090== indirectly lost: 60,053 bytes in 1,273 blocks
==7090== possibly lost: 396,167 bytes in 2,169 blocks
==7090== still reachable: 4,834,822 bytes in 31,576 blocks
==7090== suppressed: 0 bytes in 0 blocks
==7090== Reachable blocks (those to which a pointer was found) are not shown.
==7090== To see them, rerun with: –leak-check=full –show-leak-kinds=all
==7090==
==7090== For counts of detected and suppressed errors, rerun with: -v
==7090== Use –track-origins=yes to see where uninitialised values come from
==7090== ERROR SUMMARY: 20905 errors from 1583 contexts (suppressed: 15 from 2)

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Lines 3D application structure (Windows Store version)

Lines 3D game is a UWP application based on “XAML App for OpenGL ES (Universal Windows)VS2015 project template (written in C++/VS2015 using OpenGL ES 2.0 and elements of OpenGL 3.0). You can install Lines 3D  from Windows Store and play for free, or at least see the game screenshots.

Main components

Game logic and OpenGL rendering engine in Lines 3D are cross-platform. Their code uses STL, OpenGL and abstract C++ interfaces for doing the following tasks:

  • Loading sounds from wav files and playing them with different speed and volume.
  • Loading textures from PNG images (this code uses Windows API, but probably it can be made cross-platform).
  • Logging game events, such as “game over” to the Windows Store. They used to collect statistics on what game levels the users play and what score they get. The possible application crashes (unhandled exceptions and memory failures) and internal errors (like file not found, etc.) are also logged to the Windows Store.
  • Accessing application installation path and application data path in the file system.

All the graphic controls, including the main windows, application bar (main menu), dialogs, message boxes and advertising are written using XAML and Windows-specific code.

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How to compile QT 5.7 with VS2015

Below I provided a simple step by step instruction on how to compile QT 5.7 with VS2015 assuming you already have VS2015 and Git client installed on your Windows machine.

Install Perl, Python and Ruby.

To get QT 5.7 sources open Git Bash and run the following command (the repository has some submodules, so “recursive” option is required):

git clone --recursive https://github.com/qtproject/qt5.git --branch 5.7

Create a bat file called configureqt.bat with the following content:

set PATH=%PATH%;"C:\Program Files (x86)\Portable\ruby-2.3.0-i386-mingw32\bin";C:\Perl\bin;C:\Python27
D:
cd D:\Repos\qt5\
set _ROOT=D:\Repos\qt5
set PATH=%_ROOT%\qtbase\bin;%_ROOT%\gnuwin32\bin;%PATH%
set QMAKESPEC=win32-msvc2015
set _ROOT=
configure -debug -nomake examples -opensource

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Using OpenGL 3.0 with MSOpenTech ANGLE

Typically ANGLE library is used with OpenGL 2.0, but I successfully tried to enable OpenGL 3.0:

const EGLint contextAttributes[] = 
{ 
    EGL_CONTEXT_CLIENT_VERSION, 3, 
    EGL_NONE
};

and used some OpenGL 3.0 features in my Universal Windows App. But today I tried to compile my application with the new version of ANGLE library and got EGL_BAD_CONFIG error while creating the OpenGL context. The source code that returns this error checks some EGL_OPENGL_ES3_BIT_KHR that is not set in the new version:

if (clientMajorVersion == 3 && !(configuration->conformant & EGL_OPENGL_ES3_BIT_KHR))
{
    return Error(EGL_BAD_CONFIG);
}

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Debugging a C++ application on an Android device with VS2015 on Windows 10

VS2015 has an exciting ability to debug a C++ application on Android Emulator, but in this article I will talk about no less exciting and more time expensive ability to debug a C++ application on a real Android device. The first thing we need to spend the time with is figuring out how to enable USB debugging mode on our Android device. On my ASUS Zenfone I need to go to Settings->About->Software Information and tap on Build Number 7 times, after that I have USB debugging check box in Settings->Developer Options that I should tap as well:

enabling USB debugging mode on Android device USB debugging mode on Android device

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Listening to a dependency property changes in Universal Windows App in C++

If you want to be notified when some dependency property of a control changes, for example, UIElement::Visibility, you can do the following trick. First declare you own dependency property of the same type in some class:

public ref class MyListener
{
public:

    static property Windows::UI::Xaml::DependencyProperty ^ BoundVisibilityProperty
    {
        Windows::UI::Xaml::DependencyProperty ^ get() { return boundVisibilityProperty; }
    }

    property Windows::UI::Xaml::Visibility BoundVisibility
    {
        Windows::UI::Xaml::Visibility get() { return safe_cast<Windows::UI::Xaml::Visibility>(GetValue(boundVisibilityProperty)); }
        void set(Windows::UI::Xaml::Visibility value) { SetValue(boundVisibilityProperty, value); }
    }

    static Windows::UI::Xaml::DependencyProperty ^ boundVisibilityProperty;

    static void OnBoundVisibilityChanged(DependencyObject^ d, Windows::UI::Xaml::DependencyPropertyChangedEventArgs^ e);
};

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Initialization of UWP C++ XAML application

UWP C++ applications based on “DirectX 11 and XAML App” or “XAML App for OpenGL ES“ project templates have some partial App class defined in user code and in generated file App.g.h:

partial ref class App :  public ::Windows::UI::Xaml::Application,
    public ::Windows::UI::Xaml::Markup::IXamlMetadataProvider
{
public:
    void InitializeComponent();
    [Windows::Foundation::Metadata::DefaultOverload]
    virtual ::Windows::UI::Xaml::Markup::IXamlType^ GetXamlType(::Windows::UI::Xaml::Interop::TypeName type);
    virtual ::Windows::UI::Xaml::Markup::IXamlType^ GetXamlType(::Platform::String^ fullName);
    virtual ::Platform::Array<::Windows::UI::Xaml::Markup::XmlnsDefinition>^ GetXmlnsDefinitions();
private:
    ::XamlTypeInfo::InfoProvider::XamlTypeInfoProvider^ _provider;
    bool _contentLoaded;
};

the user code:

ref class App sealed
{
public:
    App();
    virtual void OnLaunched(Windows::ApplicationModel::Activation::LaunchActivatedEventArgs^ e) override;
    ...
};

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Creating cross platform (Android, iOS, UWP) OpenGLES 2 applications with VS2015

Cross platform (Android, iOS, UWP) OpenGLES 2 application can be easily created in VS2015 using “OpenGLES 2 Application (Android, iOS, Windows Universal)” project template:

“OpenGLES 2 Application (Android, iOS, Windows Universal)” project template

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Using Visual Leak Detector with MS Visual Studio 2013

Go to Tools->Extensions and Updates, download and install Using Visual Leak Detector:

Using Visual Leak Detector

Create a header file, named, for example, CommonTools.h containing the following:

#pragma once

#include "C:\Program Files (x86)\Visual Leak Detector\include\vld.h" 

#pragma comment(lib, "C:\\Program Files (x86)\\Visual Leak Detector\\lib\\Win32\\vld.lib")

Include CommonTools.h in at least one file in all the C++ projects in your solution. Build debug version of the program. Visual Leak Detector will write the information on memory leaks to Output window when the program exits.

How I fixed “error LNK2005: _DllMain@12 already defined in msvcrtd.lib”

Today I got “error LNK2005: _DllMain@12 already defined in msvcrtd.lib” while linking some C++ CLI project with MFC support in MS Visual Studio 2013. As described in A LNK2005 error occurs when the CRT library and MFC libraries are linked in the wrong order in Visual C++A LNK2005 error occurs when the CRT library and MFC libraries are linked in the wrong order in Visual C++ article, I added /verbose:lib linker option:

MS Visual Studio Linker options

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