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/*!
    \page macos.html
    \title Qt for macOS
    \brief Platform support for \macos.
    \keyword Qt for macOS
    \ingroup supportedplatform

    \macos (previously known as OS X or Mac OS X) is Apple's operating system
    for the Mac line of computers. It's a UNIX platform, based on the Darwin
    kernel, and behaves largely similar to other UNIX-like platforms.
    The main difference is that X11 is not used as the windowing system.
    Instead, \macos uses its own native windowing system that is accessible
    through the Cocoa API.

    To download and install Qt for \macos, follow the instructions on the
    \l{Getting Started with Qt} page.

    \target macos-supported-versions
    \section1 Supported Versions

    When talking about version support on \macos, it's important to distinguish
    between the  \l {Build Environment}{build environment}; the platform you're building on
    or with, and the  \l {Target Platforms}{target platforms}; the platforms you are building
    for. The following macOS versions are supported.

    \include supported-platforms.qdocinc macos

    \section2 Build Environment

    The build environment on \macos is defined \e entirely by the Xcode version used
    to build your application. Xcode contains both a toolchain (compiler, linker, and other
    tools), and a \macos platform-SDK (headers and libraries). Together these define how
    your application is built.

    \note The version of \macos that you are \e running Xcode on does not matter. As long as
    Apple ships a given Xcode version that runs on your operating system, the build
    environment will be defined by that Xcode version.

    Xcode can be downloaded from Apple's \l{https://developer.apple.com/download/}{developer
    website} (including older versions of Xcode). Once installed, choosing an Xcode installation
    is done using the \c{xcode-select} tool.

    \code
    $ sudo xcode-select --switch /Applications/Xcode.app
    \endcode

    You can inspect the globally selected Xcode installation using the same tool.

    \code
    $ xcode-select -print-path
    /Applications/Xcode.app/Contents/Developer
    \endcode

    The \c xcrun command can then be used to find a particular tool in the toolchain.

    \code
    $ xcrun -sdk macosx -find clang
    /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang
    \endcode

    or show the platform SDK path used when building.

    \code
    $ xcrun -sdk macosx --show-sdk-path
    /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk
    \endcode

    \section2 Target Platforms

    Building for \macos utilizes a technique called \e{weak linking} that allows you to build
    your application against the headers and libraries of the latest platform SDK, while still
    allowing your application to be deployed to \macos versions lower than the SDK version.
    When the binary is run on a \macos version lower than the SDK it was built with, Qt will
    check at runtime whether or not a platform feature is available before utilizing it.

    In theory this would allow running your application on every single \macos version released,
    but for practical (and technical) reasons there is a lower limit to this range, known as
    the \e{deployment target} of your application. If the binary is launched on a \macos version
    below the deployment target macOS or Qt will give an error message and the application will
    not run.

    Qt expresses the deployment target via the \c QMAKE_MACOSX_DEPLOYMENT_TARGET qmake
    variable, which has a default value set via the makespec for \macos. You should not
    need to change this default, but if needed you can increase it in your project file:

    \code
    QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.13
    \endcode

    \note You should not lower the deployment target beyond the default value set by Qt.
    Doing so will likely lead to crashes at runtime if the binary is then deployed to a
    \macos version lower than what Qt expected to run on.

    By always building against the latest available platform SDK, you ensure that
    Qt can take advantage of new features introduced in recent versions of \macos.

    For more information about SDK-based development on \macos, see Apple's \l
    {https://developer.apple.com/library/mac/#documentation/DeveloperTools/Conceptual/cross_development/Introduction/Introduction.html}{developer documentation}.

    \section3 Opting out of \macos behavior changes

    One caveat to using the latest Xcode version and SDK to build your application
    is that \macos's system frameworks will sometimes decide whether or not to
    enable behavior changes based on the SDK you built your application with.

    For example, when dark-mode was introduced in \macos 10.14 Mojave, \macos would
    only treat applications built against the 10.14 SDK as supporting dark-mode, and
    would leave applications built against earlier SDKs with the default light mode
    look. This technique allows Apple to ensure that binaries built long before
    the new SDK and operating system was released will still continue to run without
    regressions on new \macos releases.

    A consequence of this is that if Qt has problems dealing with some of these
    \macos features (dark-mode, layer-backed views), the only way to opt out of
    them is building with an earlier SDK (the 10.13 SDK, available through
    Xcode 9). This is a last-resort solution, and should only be applied if your
    application has no other ways of working around the problem.

    \section2 Architectures

    By default, Qt is built for x86_64. To build for x86_64h (Haswell). use the
    \c QMAKE_APPLE_DEVICE_ARCHS \c qmake variable.
    This is selectable at configure time:
    \code
    ./configure -platform macx-clang QMAKE_APPLE_DEVICE_ARCHS=x86_64h
    \endcode

    \c QMAKE_APPLE_DEVICE_ARCHS can also be specified as a space-delimited list
    in order to build for multiple architectures simultaneously:
    \code
    ./configure -platform macx-clang QMAKE_APPLE_DEVICE_ARCHS="x86_64 x86_64h"
    \endcode

    \section1 Additional Command-Line Options

    On the command-line, applications can be built using \c qmake and \c make.
    Optionally, \c qmake can generate project files for Xcode with
    \c{-spec macx-xcode}. If you are using the binary package, \c qmake
    generates Xcode projects by default; use \c{-spec macx-gcc} to generate
    makefiles. For example:

    \snippet snippets/code/doc_src_qtmac-as-native.qdoc 0

    Configuring with \c{-spec macx-xcode} generates an Xcode project file from
    project.pro. With \l qmake you do not have to worry about rules for Qt's
    preprocessors (\l moc and \l uic) since \l qmake automatically handles them
    and ensures that everything necessary is linked into your application.

    Qt does not entirely interact with the development environment (for
    example plugins to set a file to "mocable" from within the Xcode
    user interface).

    The result of the build process is an application bundle, which is a
    directory structure that contains the actual application executable. The
    application can be launched by double-clicking it in Finder, or by
    referring directly to its executable from the command line, for example,
    \c{myApp.app/Contents/MacOS/myApp}.

    If you wish to have a command-line tool that does not use the GUI for
    example, \c moc, \c uic or \c ls, you can tell qmake to disable bundle
    creation from the \c{CONFIG} variable in the project file:

    \code
    CONFIG -= app_bundle
    \endcode

    \section1 Deploying Applications on \macos

    \macos applications are typically deployed as self-contained application
    bundles. The application bundle contains the application executable as well
    as dependencies such as the Qt libraries, plugins, translations and other
    resources you may need. Third party libraries like Qt are normally not
    installed system-wide; each application provides its own copy.

    A common way to distribute applications is to provide a compressed disk
    image (.dmg file) that the user can mount in Finder. The deployment tool, \c
    macdeployqt (available from the \macos installers), can be used to create
    the self-contained bundles, and optionally also create a .dmg archive.
    Applications can also be distributed through the Mac App Store. Qt 5 aims
    to stay within the app store sandbox rules. macdeployqt (bin/macdeployqt)
    can be used as a starting point for app store deployment.

    \list
    \li \l{Qt for macOS - Deployment}
    \endlist

    \note For selling applications in the macOS App Store, special rules apply.
    In order to pass validation, the application must verify the existence of
    a valid receipt before executing any code. Since this is a copy protection
    mechanism, steps should be taken to avoid common patterns and obfuscate the
    code that validates the receipt as much as possible. Thus, this cannot be
    automated by Qt, but requires some platform-specific code written
    specifically for the application itself. More information can be found in
    \l{https://developer.apple.com/library/archive/releasenotes/General/ValidateAppStoreReceipt/Chapters/ValidateLocally.html}{Apple's documentation}.

    \section1 \macos Issues

    The page below covers specific issues and recommendations for creating
    \macos applications.
    \list
    \li \l{Qt for macOS - Specific Issues}
    \endlist

    \section1 Where to Go from Here

    We invite you to explore the rest of Qt. We prepared overviews to help
    you decide which APIs to use and our examples demonstrate how to use our
    API.

    \list
    \li \l{Qt Overviews} - list of topics about application development
    \li \l{Qt Examples and Tutorials}{Examples and Tutorials} - code samples and tutorials
    \li \l{Qt Reference Pages} - a listing of C++ and QML APIs
    \endlist

    Qt's vibrant and active community site, \l{http://qt.io} houses
    a wiki, a forum, and additional learning guides and presentations.

*/

/*!
    \page macos-building.html
    \title Qt for macOS - Building from Source
    \brief How to install Qt on \macos.

    \section1 Requirements

    Qt requires a macOS platform SDK and corresponding toolchain to be installed
    on the system. You can get this by installing the Xcode command line tools:

    \code
    xcode-select --install
    \endcode

    Or by downloading and installing \l{https://developer.apple.com/xcode/}{Xcode}.

    \section2 Compiler Versions

    Qt for macOS is tested and compatible with several versions of GCC (GNU
    Compiler Collection) and Clang (as available from Xcode). For a list of
    tested configurations, refer to the \e{Reference Configuration} section of
    the \l{Supported Platforms#Reference Configurations}{supported platforms}
    page.

    \section1 QDoc Dependencies

    Since version 5.11, \l {QDoc Manual}{QDoc} uses Clang to parse C++ code.
    If you wish to build QDoc manually, refer to \l {Installing Clang for QDoc}
    for specific build requirements.

    \section1 Steps for Building

    The following instructions describe how to build Qt from the source package.
    You can download the Qt 5 sources from the \l{Downloads} page. For
    more information, visit the \l{Getting Started with Qt} page.

    \section2 Step 1: Install the License File (Commercially Licensed Qt Only)

    If you use Qt with a commercial license, the Qt tools look for a local license file.
    If you are using a binary installer or the commercial Qt Creator, your licenses
    are automatically fetched and stored in your local user profile
    (\c{$HOME/Library/Application Support/Qt/qtlicenses.ini} file).

    If you do not use any binary installer or Qt Creator, you can download
    the respective license file from your \l {Qt Account} Web portal and save
    it to your user profile as \c{$HOME/.qt-license}. If you prefer a
    different location or file name, you need to set the \c{QT_LICENSE_FILE}
    environment variable to the respective file path.

    \section2 Step 2: Unpack the Archive

        Unpack the archive if you have not done so already. For example,
        if you have the \c{qt-everywhere-opensource-src-%VERSION%.tar.gz}
        package, type the following commands at a command line prompt:

    \snippet snippets/code/doc_src_installation.qdoc 11

        This creates the directory \c{/tmp/qt-everywhere-opensource-src-%VERSION%}
        containing the files from the archive.

    \section2 Step 3: Build the Qt Library

        To configure the Qt library for your machine type, run the
        \c{./configure} script in the package directory.

        By default, Qt is configured for installation in the
        \c{/usr/local/Qt-%VERSION%} directory, but this can be
        changed by using the \c{-prefix} option.

    \snippet snippets/code/doc_src_installation.qdoc 12

        By default, Qt is built as a framework, but you can built
        it as a set of dynamic libraries (dylibs) by specifying the
        \c{-no-framework} option.

        Qt can also be configured to be built with debugging symbols. This
        process is described in detail in the \l{Debugging Techniques}
        document.

        The \l{Qt Configure Options}{Configure Options} page contains more
        information about the configure options.

        To create the library and compile all the examples and tools, type:

    \snippet snippets/code/doc_src_installation.qdoc 13

        If \c{-prefix} is outside the build directory, you need to install
        the library, examples, and tools in the appropriate place. To do this,
        type:

    \snippet snippets/code/doc_src_installation.qdoc 14

        This command requires that you have administrator access
        on your machine.

        \note There is a potential race condition when running make install with multiple
        jobs. It is best to only run one make job (-j1) for the install.

    \section2 Step 4: Set the Environment Variables

        In order to use Qt, some environment variables need to be
        extended.

    \snippet snippets/code/doc_src_installation.qdoc 15

        This is done like this:

        In \c{.profile} (if your shell is bash), add the following lines:

    \snippet snippets/code/doc_src_installation.qdoc 16

        In \c{.login} (in case your shell is csh or tcsh), add the following line:

    \snippet snippets/code/doc_src_installation.qdoc 17

        If you use a different shell, please modify your environment
        variables accordingly.

    \b {Qt is now installed.}

    \section1 Step 5: Build the Qt Documentation

    For the Qt reference documentation to be available in \l {Qt Assistant}, you
    must build it separately:

    \snippet snippets/code/doc_src_installation.qdoc 24

    \section1 Limitations

    \section2 Fink

    If you have installed the Qt for X11 package from \l{http://www.finkproject.org/}{Fink},
    it will set the \c QMAKESPEC environment variable to \c darwin-g++. This will cause
    problems when you build the Qt for macOS package. To fix this, simply unset your \c
    QMAKESPEC or set it to \c macx-g++ before you run \c configure. To get a
    fresh Qt distribution, run \c{make confclean} on the command-line.
*/

/*!
    \page macos-issues.html
    \title Qt for macOS - Specific Issues
    \brief A description of issues with Qt that are specific to \macos.

    This page outlines the main issues regarding \macos support in Qt.
    \macos terminologies and specific processes are found at
    \l{https://developer.apple.com/}.

    \section1 Aqua

    The Aqua style is an essential part of the \macos platform. As with Cocoa, Qt provides widgets that
    look like those described in the \l{https://developer.apple.com/design/human-interface-guidelines/macos/overview/themes/}
    {\macos Human Interface Guidelines}. Note that although Qt's widgets use AppKit under the hood for
    look and feel, it does not represent each individual Qt Widget as a wrapped native control.

    The \l{Qt Widget Gallery} page contains sample images of applications using
    the \macos platform theme.

    \section2 Qt Attributes for \macos

    The following lists a set of useful attributes that can be used to tweak
    applications on \macos:

    \list
    \li Qt::AA_MacPluginApplication
    \li Qt::AA_DontUseNativeMenuBar
    \li Qt::AA_MacDontSwapCtrlAndMeta
    \li Qt::WA_MacNoClickThrough
    \li Qt::WA_MacOpaqueSizeGrip
    \li Qt::WA_MacShowFocusRect
    \li Qt::WA_MacNormalSize
    \li Qt::WA_MacSmallSize
    \li Qt::WA_MacMiniSize
    \li Qt::WA_MacVariableSize
    \li Qt::WA_MacBrushedMetal
    \li Qt::WA_MacAlwaysShowToolWindow
    \li Qt::WA_MacFrameworkScaled
    \li Qt::WA_MacNoShadow
    \li Qt::Sheet
    \li Qt::Drawer
    \li Qt::MacWindowToolBarButtonHint,
    \li QMainWindow::unifiedTitleAndToolBarOnMac
    \endlist

    \macos always double buffers the screen, therefore, the
    Qt::WA_PaintOnScreen attribute has no effect. Also it is impossible to paint
    outside of a paint event so Qt::WA_PaintOutsidePaintEvent has no effect
    either.

    \section2 Right Mouse Clicks

    The QContextMenuEvent class provides right mouse click support for \macos
    applications. This will map to a context menu event, for example, a menu
    that will display a pop-up selection. This is the most common use of right
    mouse clicks, and maps to a control-click with the \macos one-button mouse
    support.

    \section2 Menu Bar

    Qt detects menu bars and turns them into Mac native menu bars. Fitting this
    into existing Qt applications is normally automatic. However, if you
    have special needs, the Qt implementation currently selects a menu bar by
    starting at the active window (for example, QGuiApplication::focusWindow())
    and applying the following tests:

    \list 1
    \li If the window has a QMenuBar, then it is used.
    \li If the window is modal, then its menu bar is used. If no menu
       bar is specified, then a default menu bar is used (as
       documented below).
    \li If the window has no parent, then the default menu bar is used
       (as documented below).
    \endlist

    These tests are followed all the way up the parent window chain
    until one of the above rules is satisfied. If all else fails, a
    default menu bar will be created. The default menu bar on
    Qt is an empty menu bar. However, you can create a different
    default menu bar by creating a parentless QMenuBar. The first one
    created will be designated the default menu bar and will be used
    whenever a default menu bar is needed.

    Using native menu bars introduces certain limitations on Qt classes. The
    section with the \l{#Limitations}{list of limitations} below has more
    information.

    Qt provides support for the Global Menu Bar with QMenuBar. \macos users
    expect to have a menu bar at the top of the screen and Qt honors this.

    Additionally, users expect certain conventions to be respected, for example
    the application menu should contain \gui About, \gui Preferences, \gui Quit,
    and so on. Qt handles these conventions, although it does not provide a
    means of interacting directly with the application menu.

    Each \l QAction has a \l{QAction::menuRole}{menuRole} property which
    controls the special placement of application menu items; however by
    default the \c menuRole is \l{QAction::TextHeuristicRole}{TextHeuristicRole}
    which mean the menu items will be auto-detected by their \l{QAction::text}{text}.

    Other standard menu items such as \gui Cut, \gui Copy, \gui Paste and
    \gui{Select All} are applicable both in your application and in some
    native dialogs such as \l QFileDialog. It's important that you create these
    menu items with the standard shortcuts so that the corresponding editing
    features will be enabled in the dialogs. At this time there are no
    \c MenuRole identifiers for them, but they will be auto-detected
    just like the application menu items when the \c QAction has the default
    \l{QAction::TextHeuristicRole}{TextHeuristicRole}.

    \section2 Special Keys

    To provide the expected behavior for Qt applications on \macos,
    the Qt::Key_Meta, Qt::MetaModifier, and Qt::META enum values
    correspond to the Control keys on the standard Apple keyboard,
    and the Qt::Key_Control, Qt::ControlModifier, and Qt::CTRL enum values
    correspond to the Command keys.

    \section2 Dock

    Interaction with the dock is possible. The icon can be set by calling
    QWindow::setWindowIcon() from the main window in your application. The
    setWindowIcon() call can be made as often as necessary, providing an
    icon that can be easily updated.

    \section2 Accessiblity

    Many users interact with \macos with assistive devices. With Qt the aim is
    to make this automatic in your application so that it conforms to accepted
    practice on its platform. Qt uses Apple's accessibility framework to provide
    access to users with disabilities.

    \section1 Library and Deployment Support

    Qt provides support for \macos structures such as Frameworks and bundles.
    It is important to be aware of these structure as they directly affect the
    deployment of applications.

    Qt provides a deploy tool, \l{The Mac Deployment Tool}{macdeployqt}, to
    simplify the deployment process. The \l{Qt for macOS - Deployment}
    article covers the deployment process in more detail.

    \section2 Qt Libraries as Frameworks

    By default, Qt is built as a set of frameworks. Frameworks are the
    \macos preferred way of distributing libraries. The
    \l{http://developer.apple.com/documentation/MacOSX/Conceptual/BPFrameworks/index.html}
    {Apple's Framework Programming Guide} site has far more information about
    Frameworks.

    It is important to remember that Frameworks always link with \e release
    versions of libraries. If the \e{debug} version of a Qt framework is
    desired, use the \c DYLD_IMAGE_SUFFIX environment variables to ensure that
    the debug version is loaded:

    \code
    export DYLD_IMAGE_SUFFIX=_debug
    \endcode

    Alternatively, you can temporarily swap your debug and release versions,
    which is documented in
    \l{http://developer.apple.com/technotes/tn2004/tn2124.html#SECJUSTONELIB}
    {Apple's "Debugging Magic" technical note}.

    If you don't want to use frameworks, simply configure Qt with
    \c{-no-framework}.

    \code
    ./configure -no-framework
    \endcode

    \section2 Bundle-Based Libraries

    If you want to use some dynamic libraries in the \macos
    application bundle (the application directory), create a
    subdirectory named \e Frameworks in the application bundle
    directory and place your dynamic libraries there. The application
    will find a dynamic library if it has the install name
    \e{@executable_path/../Frameworks/libname.dylib}.

    If you use \c qmake and Makefiles, use the \c QMAKE_LFLAGS_SONAME setting:

    \snippet snippets/code/doc_src_mac-differences.pro 0

    Alternatively, you can modify the install name using the
    \c{install_name_tool(1)} on the command line.

    The \c DYLD_LIBRARY_PATH environment variable will override these settings,
    and any other default paths, such as a lookup of dynamic libraries inside
    \e /usr/lib and similar default locations.

    If you are using older versions of GDB you must run with the full
    path to the executable. Later versions allow you to pass the
    bundle name on the command line.

    \section2 Combining Libraries

    If you want to build a new dynamic library combining the Qt 4
    dynamic libraries, you need to introduce the \c{ld -r} flag. Then
    relocation information is stored in the output file, so that
    this file could be the subject of another \c ld run. This is done
    by setting the \c -r flag in the \c .pro file, and the \c LFLAGS
    settings.

    \section2 Initialization Order

    \c dyld(1) calls global static initializers in the order they are
    linked into the application. If a library links against Qt and
    references the globals in Qt (from global initializers in your own
    library), link the application against Qt before
    linking it against the library. Otherwise the result will be
    undefined because Qt's global initializers have not been called
    yet.

    \section1 Compile-Time Flags

    The following flags are helpful when you want to define \macos specific
    code:

    \list
    \li \c Q_OS_DARWIN is defined when Qt detects you are on a
    Darwin-based system such as \macos or iOS.
    \li \c Q_OS_MACOS is defined when you are on an \macos system.
    \endlist

    \note \c Q_WS_MAC is no longer defined in Qt 5.

    If you want to define code for specific versions of \macos, use
    the availability macros defined in \e{/usr/include/AvailabilityMacros.h}.

    The QSysInfo documentation has information about runtime version checking.

    \section1 \macos Native API Access

    \section2 Accessing the Bundle Path

    \macos applications are structured as a directory (ending with \e .app).
    This directory contains sub-directories and files. It may be useful to place
    items, such as plugins and online documentation, inside this bundle. The
    following code returns the path of the application bundle:

    \snippet snippets/code/doc_src_mac-differences.cpp 1

    \note When \macos is set to use Japanese, a bug causes this sequence
    to fail and return an empty string. Therefore, always test the
    returned string.

    For more information about using the CFBundle API, visit
    \l{http://developer.apple.com/documentation/CoreFoundation/Reference/CFBundleRef/index.html}
    {Apple's Developer Website}.

    QCoreApplication::applicationDirPath() can be used to determine
    the path of the binary within the bundle.

    \section2 Translating the Application Menu and Native Dialogs

    The items in the Application Menu will be merged correctly for
    localized applications, but they will not show up translated
    until the application bundle contains a localized resource folder.
    to the application bundle.

    Essentially, there needs to be a file called
    \e locversion.plist. Here is an example of an application with Norwegian
    localization:

    \snippet snippets/code/doc_src_mac-differences.qdoc 2

    Afterwards, when the application is run with the preferred language set to
    Norwegian, the menu items should display \gui Avslutt instead of \gui Quit.

    The \l{http://developer.apple.com/library/mac/#documentation/CoreFoundation/Conceptual/CFBundles/BundleTypes/BundleTypes.html#//apple_ref/doc/uid/10000123i-CH101-SW13}{Bundle Programming Guide}
    contains information about bundles and the localized resource folder.

    \section2 Mixing Qt with Native Code

    Two classes are available for adding native Cocoa views and controls
    inside a Qt application, or for embedding Qt into a native
    Cocoa application: QMacCocoaViewContainer, and QMacNativeWidget.

    \section2 Using Native Cocoa Panels

    Qt's event dispatcher is more flexible than what Cocoa offers, and lets the
    user spin the event dispatcher (and running QEventLoop::exec) without having
    to think about whether or not modal dialogs are showing on screen (which is
    a difference compared to Cocoa). Therefore, we need to do extra management
    in Qt to handle this correctly, which unfortunately makes mixing native
    panels hard. The best way at the moment to do this, is to follow the pattern
    below, where we post the call to the function with native code rather than
    calling it directly. Then we know that Qt has cleanly updated any pending
    event loop recursions before the native panel is shown:

    \code
        #include <QtGui>

        class NativeProxyObject : public QObject
        {
            Q_OBJECT
        public slots:
            void execNativeDialogLater()
            {
                QMetaObject::invokeMethod(this, "execNativeDialogNow", Qt::QueuedConnection);
            }

            void execNativeDialogNow()
            {
                NSRunAlertPanel(@"A Native dialog", @"", @"OK", @"", @"");
            }

        };

        #include "main.moc"

        int main(int argc, char **argv){
            QApplication app(argc, argv);
            NativeProxyObject proxy;
            QPushButton button("Show native dialog");
            QObject::connect(&button, SIGNAL(clicked()), &proxy, SLOT(execNativeDialogLater()));
            button.show();
            return app.exec();
        }
    \endcode

    \section1 Limitations

    \section2 MySQL and \macos

    There seems to be a issue when both \c -prebind and \c -multi_module are
    defined when linking static C libraries into dynamic libraries. If you
    get the following error message when linking Qt:

    \snippet snippets/code/doc_src_platform-notes.qdoc 6

    re-link Qt using -single_module. This is only a problem when building the
    MySQL driver into Qt. It does not affect plugins or static builds.

    \section2 D-Bus and \macos

    The QtDBus module defaults to dynamically loading the libdbus-1 library on
    \macos. That means applications linking against the QtDBus module will
    load even on \macos systems that do not have the libraries, but they
    will fail to connect to any D-Bus server and they will fail to open a
    server using QDBusServer.

    To use D-Bus functionality, you need to install the libdbus-1 library, for
    example through Homebrew, Fink or MacPorts. You may want to include those
    libraries in your application's bundle if you're deploying to other
    systems. Additionally, note that there is no system bus on \macos and
    that the session bus will only be started after launchd is configured to
    manage it.

    \section2 Menu Actions

    \list
    \li Actions in a QMenu with accelerators that have more than one
       keystroke (QKeySequence) will not display correctly, when the
       QMenu is translated into a Mac native menu bar. The first key
       will be displayed. However, the shortcut will still be
       activated as on all other platforms.

    \li QMenu objects used in the native menu bar are not able to
       handle Qt events via the normal event handlers.
       Install a delegate on the menu itself to be notified of these
       changes. Alternatively, consider using the QMenu::aboutToShow()
       and QMenu::aboutToHide() signals to keep track of menu visibility;
       these provide a solution that should work on all platforms
       supported by Qt.

    \li By default, Qt creates a native \b Quit menu item that will react
       to the \c {CMD+Q} shortcut. Creating a QAction for the QAction::QuitRole
       role will replace that menu item. Therefore, the replacement action
       should be connected to either the QCoreApplication::quit slot, or a
       custom slot that stops the application.
    \endlist

    \section2 Native Widgets

    Qt has support for sheets, represented by the window flag, Qt::Sheet.

    Usually, when referring to a native \macos application, \e native means an
    application that interfaces directly to the underlying window system, rather
    than one that uses some intermediary layer. Qt applications run as first
    class citizens, just like Cocoa applications. We use Cocoa
    internally to communicate with the operating system.

*/

/*!
    \page macos-deployment.html
    \title Qt for macOS - Deployment
    \brief Describes the deployment process for \macos.

    This document describes how to create a \l{Qt for macOS}{\macos} bundle
    and make sure that the application finds the resources it needs at run-time.
    We demonstrate the procedures in terms of deploying the
    \l{tools/plugandpaint/app}{Plug & Paint} example application that comes with the
    Qt installation package.

    The Qt installers for \macos include a \l
    {macdeploy}{deployment tool} that automates the procedures described here.

    \section1 The Bundle

    On \macos, a GUI application must be built and run from a bundle, which is a
    directory structure that appears as a single  entity when viewed in the
    Finder. A bundle for an application typically contains the executable and
    all the resources it needs. Here is the snapshot of an application bundle
    structure:

    \image deployment-mac-bundlestructure.png

    The bundle provides many advantages to the user:
    \list
     \li It is easily installable as it is identified as a single entity.
     \li Information about a bundle is accessible from code.
    \endlist
    This is specific to \macos and beyond the scope of this document. For
    more information about bundles, see
    \l {http://developer.apple.com/documentation/CoreFoundation/Conceptual/CFBundles/index.html}{Apple's Developer Website}.

    \c{qmake} automatically generates a bundle for your application. To disable this,
    add the following statement to your application's project file (\c{.pro}):

    \snippet snippets/code/doc_src_deployment.pro 26

    \section1 Static Linking

    If you want to keep things simple and have a few files to
    deploy, you must build your application with statically linked libraries.

    \section2 Building Qt Statically

    Start by installing a static version of the Qt library. Remember that you
    cannot use plugins and that you must build the dependent libraries such
    as image formats, SQL drivers, and so on with static linking.

    \snippet snippets/code/doc_src_deployment.qdoc 27

    You can check the various options that are available by running \c
    configure -help.

    \section2 Linking the Application to the Static Version of Qt

    Once Qt is built statically, the next step is to regenerate the
    makefile and rebuild the application. First, we must go into the
    directory that contains the application:

    \snippet snippets/code/doc_src_deployment.qdoc 28

    Now run \c qmake to create a new makefile for the application, and do
    a clean build to create the statically linked executable:

    \snippet snippets/code/doc_src_deployment.qdoc 29

    You probably want to link against the release libraries, and you
    can specify this when invoking \c qmake. If you have Xcode Tools
    1.5 or higher installed, you may want to take advantage of "dead
    code stripping" to reduce the size of your binary even more. You
    can do this by passing \c {LIBS+= -dead_strip} to \c qmake in
    addition to the \c {-config release} parameter.

    Now, provided that everything compiled and linked without any
    errors, we should have a \c plugandpaint.app bundle ready
    for deployment. Try installing the bundle on a machine running \macos
    that does not have Qt or any Qt applications installed.

    You can check what other libraries your application links to using
    the \c otool:

    \snippet snippets/code/doc_src_deployment.qdoc 30

    Here is what the output looks like for the statically linked
    \l {tools/plugandpaint/app}{Plug & Paint}:

    \snippet snippets/code/doc_src_deployment.qdoc 31

    If you see \e Qt libraries in the output, it probably
    means that you have both dynamic and static Qt libraries installed
    on your machine. The linker always chooses dynamic linking over
    static. If you want to use only static libraries, you can either:
    \list
     \li move your Qt dynamic libraries (\c .dylibs) away to another directory
         while you link the application and then move them back,
     \li or edit the \c Makefile  and replace link lines for the Qt libraries
         with the absolute path to the static libraries.
    \endlist

    For example, replace the following:

    \snippet snippets/code/doc_src_deployment.qdoc 32

    with this:

    \snippet snippets/code/doc_src_deployment.qdoc 33

    The \l {tools/plugandpaint/app}{Plug & Paint} example consists of
    several components: The core application (\l
    {tools/plugandpaint/app}{Plug & Paint}), and the \l
    {tools/plugandpaint/plugins/basictools}{Basic Tools} and \l
    {tools/plugandpaint/plugins/extrafilters}{Extra Filters}
    plugins. As we cannot deploy plugins using the static linking
    approach, the bundle we have prepared so far is incomplete. The
    application will run, but the functionality will be disabled due
    to the missing plugins. To deploy plugin-based applications we
    should use the framework approach, which is specific to \macos.

    \section1 Frameworks

    In this approach, ensure that the Qt runtime is redistributed correctly
    with the application bundle, and that the plugins are installed in the correct
    location so that the application finds them.

    There are two ways to distribute Qt with your application in the frameworks
    approach:
    \list
     \li Private framework within your application bundle.
     \li Standard framework (alternatively use the Qt frameworks in
    the installed binary).
    \endlist

    The former is good if you have Qt built in a special way, or want to make
    sure the framework is there. It just comes down to where you place the Qt
    frameworks.

    The latter option is good if you have many Qt applications and you want
    them use a single Qt framework rather than multiple versions of it.

    \section2 Building Qt as Frameworks

    We assume that you already have installed Qt as frameworks, which
    is the default when installing Qt, in the /path/to/Qt
    directory. For more information on how to build Qt without Frameworks,
    visit the \l{Qt for macOS - Specific Issues} documentation.

    When installing, the identification name of the frameworks is set. This
    name is used by the dynamic linker (\c dyld) to find the libraries for your
    application.

    \section2 Linking the Application to Qt as Frameworks

    After building Qt as frameworks, we can build the \l
    {tools/plugandpaint/app}{Plug & Paint} application. First, we must go
    to the directory that contains the application:

    \snippet snippets/code/doc_src_deployment.qdoc 34

    Run \c qmake to create a new makefile for the application, and do
    a clean build to create the dynamically linked executable:

    \snippet snippets/code/doc_src_deployment.qdoc 35

    This builds the core application. Use the following to build the plugins:

    \snippet snippets/code/doc_src_deployment.qdoc 36

    Now run the \c otool for the Qt frameworks, for example Qt Gui:

    \snippet snippets/code/doc_src_deployment.qdoc 37

    You would get the following output:

    \snippet snippets/code/doc_src_deployment.qdoc 38

    For the Qt frameworks, the first line (i.e. \c
    {path/to/Qt/lib/QtGui.framework/Versions/4/QtGui (compatibility
    version 4.0.0, current version 4.0.1)}) becomes the framework's
    identification name which is used by the dynamic linker (\c dyld).

    But when you are deploying the application, your users may not
    have the Qt frameworks installed in the specified location. For
    that reason, you must either provide the frameworks in an agreed
    location, or store the frameworks in the bundle.
    Regardless of which solution you choose, you must make sure that
    the frameworks return the proper identification name for
    themselves, and that the application looks for these names.
    Luckily we can control this with the \c install_name_tool
    command-line tool.

    The \c install_name_tool works in two modes, \c -id and \c
    -change. The \c -id mode is for libraries and frameworks, and
    allows us to specify a new identification name. We use the \c
    -change mode to change the paths in the application.

    Let's test this out by copying the Qt frameworks into the Plug &
    Paint bundle. Looking at \c otool's output for the bundle, we can
    see that we must copy both the QtCore and QtGui frameworks into
    the bundle. We will assume that we are in the directory where we
    built the bundle.

    \snippet snippets/code/doc_src_deployment.qdoc 39

    First we create a \c Frameworks directory inside the bundle. This
    follows the \macos application convention. We then copy the
    frameworks into the new directory. As frameworks contain
    symbolic links, we use the \c -R option.

    \snippet snippets/code/doc_src_deployment.qdoc 40

    Then we run \c install_name_tool to set the identification names
    for the frameworks. The first argument after \c -id is the new
    name, and the second argument is the framework that we want to
    rename.  The text \c @executable_path is a special \c dyld variable
    telling \c dyld to start looking where the executable is located. The new
    names specifies that these frameworks are located in the directory directly
    under the \c Frameworks directory.

    \snippet snippets/code/doc_src_deployment.qdoc 41

    Now, the dynamic linker knows where to look for QtCore and
    QtGui. We must ensure that the application also knows where to find the
    library, using \c install_name_tool's \c -change mode.
    This basically comes down to string replacement, to match the
    identification names that we set earlier to the frameworks.

    Finally, the QtGui framework depends on QtCore, so we must
    remember to change the reference for QtGui:

    \snippet snippets/code/doc_src_deployment.qdoc 42

    After this, we run \c otool again and see that the
    application can find the libraries.

    The plugins for the \l {tools/plugandpaint/app}{Plug &
    Paint} example makes it interesting. The basic steps we
    need to follow with plugins are:

    \list
        \li put the plugins inside the bundle,
        \li run the \c install_name_tool to check whether the plugins are using
            the correct library,
        \li and ensure that the application knows where to look for the plugins.
    \endlist

    We can put the plugins anywhere we want in the bundle, but the
    best location is to put them under Contents/Plugins. When we built
    the Plug & Paint plugins, based on the \c DESTDIR variable in their \c .pro
    file, the plugins' \c .dylib files are in the \c plugins subdirectory
    under the \c plugandpaint directory. We just have to move this directory
    to the correct location.

    \snippet snippets/code/doc_src_deployment.qdoc 43

    For example, If we run \c otool on the \l
    {tools/plugandpaint/plugins/basictools}{Basic Tools} plugin's \c
    .dylib file, we get the following information.

    \snippet snippets/code/doc_src_deployment.qdoc 44

    Then we can see that the plugin links to the Qt frameworks it was
    built against. As we want the plugins to use the framework in
    the application bundle, we change them the same way as we did for
    the application. For example for the Basic Tools plugin:

    \snippet snippets/code/doc_src_deployment.qdoc 45


    We must also modify the code in \c
    tools/plugandpaint/mainwindow.cpp to \l {QDir::cdUp()}{cdUp()} to ensure
    that the application finds the plugins. Add the following
    code to the \c mainwindow.cpp file:

    \snippet snippets/code/doc_src_deployment.qdoc 46

    \table
    \row
    \li \inlineimage deployment-mac-application.png
    \li
    The additional code in \c tools/plugandpaint/mainwindow.cpp also
    enables us to view the plugins in the Finder, as shown in the image.

    We can also add plugins extending Qt, for example adding SQL
    drivers or image formats. We just need to follow the directory
    structure outlined in plugin documentation, and make sure they are
    included in the QCoreApplication::libraryPaths(). Let's quickly do
    this with the image formats, following the procedure outlined earlier.

    Copy Qt's image format plugins into the bundle:

    \snippet snippets/code/doc_src_deployment.qdoc 47

    Use \c install_name_tool to link the plugins to the frameworks in
    the bundle:

    \snippet snippets/code/doc_src_deployment.qdoc 48

    Update the source code in \c tools/plugandpaint/main.cpp
    to look for the new plugins. After constructing the
    QApplication, we add the following code:

    \snippet snippets/code/doc_src_deployment.cpp 49

    First, we tell the application to only look for plugins in this
    directory. In our case, we want the application to look for only those
    plugins that we distribute with the bundle. If we
    were part of a bigger Qt installation we could have used
    QCoreApplication::addLibraryPath() instead.

    \endtable

    \warning While deploying plugins, we make changes to the
    source code and that resets the default identification names when
    the application is rebuilt. So you must repeat the process of
    making your application link to the correct Qt frameworks in the bundle
    using \c install_name_tool.

    Now you should be able to move the application to another \macos
    machine and run it without Qt installed. Alternatively, you can
    move your frameworks that live outside of the bundle to another
    directory and see if the application still runs.

    If you store the frameworks in another location outside the
    bundle, the technique of linking your application is similar; you
    must make sure that the application and the frameworks agree where
    to be looking for the Qt libraries as well as the plugins.

    \section2 Creating the Application Package

    When you are done linking your application to Qt, either
    statically or as frameworks, the application is ready to be
    distributed. For more information, refer to the
    \l {https://developer.apple.com/}{Apple Developer} website.

    Although the process of deploying an application do have some
    pitfalls, once you know the various issues you can easily create
    packages that all your \macos users will enjoy.

    \section1 Application Dependencies

    \section2 Qt Plugins

    All Qt GUI applications require a plugin that implements the \l {Qt
    Platform Abstraction} (QPA) layer in Qt 5. For \macos, the name of the
    platform plugin is \c {libqcocoa.dylib}. This file must be located within a
    specific subdirectory (by default, \c platforms) under your distribution
    directory. Alternatively, it is possible to adjust the search path Qt
    uses to find its plugins, as described below.

    Your application may also depend on one or more Qt plugins, such as the JPEG
    image format plugin or a SQL driver plugin. Be sure to distribute any Qt
    plugins that you need with your application. Similar to the platform plugin,
    each type of plugin must be located within a specific subdirectory (such as
    \c imageformats or \c sqldrivers) in your distribution directory.

    The search path for Qt plugins (as well as a few other paths) is
    hard-coded into the QtCore library. By default, the first plugin
    search path will be hard-coded as \c /path/to/Qt/plugins. But
    using pre-determined paths has certain disadvantages. For example,
    they may not exist on the target machine. So you must check
    various alternatives to ensure that the Qt plugins are found:

    \list

    \li \l{qt-conf.html}{Using \c qt.conf}. This is the recommended
    approach as it provides the most flexibility.

    \li Using QApplication::addLibraryPath() or
    QApplication::setLibraryPaths().

    \li Using a third party installation utility to change the
    hard-coded paths in the QtCore library.

    \endlist

    The \l{How to Create Qt Plugins} document outlines the issues you
    need to pay attention to when building and deploying plugins for
    Qt applications.

    \section2 Additional Libraries

    You can check which libraries your application is linking against
    by using \c otool. Run this with the application path as an argument:

    \snippet snippets/code/doc_src_deployment.qdoc 50

    Compiler-specific libraries rarely have to be redistributed with your
    application. But there are several ways to deploy applications, as Qt can be
    configured, built, and installed in several ways on \macos. Typically your
    goals help determine how you are going to deploy the application. The last
    sections describe a few things that you must be aware of while deploying
    your application.

    \section2 \macos Version Dependencies

    \include expressing-apple-os-versions.qdocinc expressing os versions

    \section1 The Mac Deployment Tool
    \target macdeploy
    The Mac deployment tool can be found in QTDIR/bin/macdeployqt. It is
    designed to automate the process of creating a deployable
    application bundle that contains the Qt libraries as private
    frameworks.

    The mac deployment tool also deploys the Qt plugins, according
    to the following rules (unless \c {-no-plugins} option is used):
    \list
    \li The platform plugin is always deployed.
    \li Debug versions of the plugins are not deployed.
    \li The designer plugins are not deployed.
    \li The image format plugins are always deployed.
    \li The print support plugin is always deployed.
    \li SQL driver plugins are deployed if the application uses the \l{Qt SQL} module.
    \li Script plugins are deployed if the application uses the \l{Qt Script} module.
    \li The SVG icon plugin is deployed if the application uses the \l{Qt SVG} module.
    \li The accessibility plugin is always deployed.
    \endlist

    To include a 3rd party library in the application bundle, copy the library
    into the bundle manually, after the bundle is created.

    \c macdeployqt supports the following options:
    \table
    \header
        \li Option
        \li Description
    \row
        \li \c{-verbose=<0-3>}
        \li 0 = no output, 1 = error/warning (default), 2 = normal, 3 = debug
    \row
        \li \c{-no-plugins}
        \li Skip plugin deployment
    \row
        \li \c{-dmg}
        \li Create a .dmg disk image
    \row
        \li \c{-no-strip}
        \li Don't run 'strip' on the binaries
    \row
        \li \c{-use-debug-libs}
        \li Deploy with debug versions of frameworks and plugins (implies
            \c{-no-strip})
    \row
        \li \c{-executable=<path>}
        \li Let the given executable also use the deployed frameworks
    \row
        \li \c{-qmldir=<path>}
        \li Deploy imports used by .qml files in the given path
    \row
        \li \c{-qmlimport=<path>}
        \li Add the given path to the QML imports search locations
    \row
        \li \c{-always-overwrite}
        \li Copy files even if the target file exists
    \row
        \li \c{-codesign=<ident>}
        \li Run \c codesign with the given identity on all executables
    \row
        \li \c{-hardened-runtime}
        \li Enable Hardened Runtime when code signing
    \row
        \li \c{-timestamp}
        \li Include a secure timestamp when code signing (requires internet connection)
    \row
        \li \c{-sign-for-notarization=<ident>}
        \li Activate the necessary options for notarization (requires internet connection). The activated options are \c{-hardened-runtime}, \c{-timestamp} and \c{-codesign=<ident>}
    \row
        \li \c{-appstore-compliant}
        \li Skip deployment of components that use private API
    \row
        \li \c{-libpath=<path>}
        \li Add the given path to the library search path
    \row
        \li \c{-fs=<filesystem>}
        \li Set the filesystem used for the .dmg disk image (defaults to HFS+)
    \endtable

    \note macOS High Sierra introduced the new Apple File System (APFS). Older
    versions of macOS cannot read .dmg files that are formatted with APFS. By
    default, \c macdeployqt uses the older HFS+ file system for compatibility
    with all versions of macOS currently supported by Qt. Use the \c{-fs} option
    to specify a different file system.

    \section1 Volume Name

    The volume name of a disk image (the text displayed in the window title of
    an opened \c .dmg file) created with \c -dmg is based on the path to the
    application when \c macdeployqt is run. For example, consider the following
    command that creates a disk image for a Qt Quick application:

    \badcode
    macdeployqt /Users/foo/myapp-build/MyApp.app -qmldir=/Users/foo/myapp/qml -dmg
    \endcode

    The resulting volume name will be:

    \badcode
    /Users/foo/myapp-build/MyApp.app
    \endcode

    To ensure that the volume name only contains the application name and not
    the path on the deployment machine, run \c macdeployqt in the same
    directory:

    \badcode
    cd /Users/foo/myapp-build
    macdeployqt MyApp.app -qmldir=/Users/foo/myapp/qml -dmg
    \endcode

    The resulting volume name will then be:

    \badcode
    MyApp.app
    \endcode
*/