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**
** Copyright (C) 2005-2008 Trolltech ASA. All rights reserved.
**
** This file is part of the Qt GUI Toolkit.
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**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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****************************************************************************/

/*!
    \group deployment
    \title Deploying Qt Applications
    \ingroup buildsystem

    Deploying an Qt application does not require any C++
    programming. All you need to do is to build Qt and your
    application in release mode, following the procedures described in
    this documentation. We will demonstrate the procedures in terms of
    deploying the \l {tools/plugandpaint}{Plug & Paint} application
    that is provided in Qt's examples directory.

    There are two ways of deploying an application:

    \list
        \o Static Linking
        \o Shared Libraries (Frameworks on Mac)
    \endlist

    Static linking results in a stand-alone executable. The advantage
    is that you will only have a few files to deploy. The
    disadvantages are that the executables are large and with no
    flexibility (i.e a new version of the application, or of Qt, will
    require that the deployment process is repeated), and that you
    cannot deploy plugins.

    To deploy plugin-based applications, you can use the shared
    library approach. Shared libraries also provide smaller, more
    flexible executables. For example, using the shared library
    approach, the user is able to independently upgrade the Qt library
    used by the application.

    Another reason why you might want to use the shared library
    approach, is if you want to use the same Qt libraries for a family
    of applications. In fact, if you download the binary installation
    of Qt, you get Qt as a shared library.

    The disadvantage with the shared library approach is that you
    will get more files to deploy.

    \table 100%
    \header
        \o {5,1} Qt's Libraries
    \row
        \o \l {QtCore}
        \o \l {QtGui}
        \o \l {QtNetwork}
        \o \l {QtOpenGL}
        \o \l {QtSql}
    \row
        \o \l {QtSvg}
        \o \l {QtXml}
        \o \l {QtDesigner}
        \o \l {QtAssistant}
        \o \l {Qt3Support}
    \endtable

    Since Qt is not a system library, it has to be redistributed along
    with your application; the minimum is to redistribute the run-time
    of the libraries used by the application.  Using static linking,
    however, the Qt run-time is compiled into the executable.

    In particular, you will need to deploy Qt plugins, such as
    JPEG support or SQL drivers. For more information about plugins,
    see the \l {plugins-howto.html}{How to Create Qt Plugins}
    documentation.

    When deploying an application using the shared library approach
    you must ensure that the Qt libraries will use the correct path to
    find the Qt plugins, documentation, translation etc. To do this you
    can use a \c qt.conf file. For more information, see the \l {Using
    qt.conf} documentation.

    Depending on configuration, compiler specific libraries must be
    redistributed as well. For more information, see the platform
    specific Application Dependencies sections: \l
    {deployment-x11.html#application-dependencies}{X11}, \l
    {deployment-windows.html#application-dependencies}{Windows}, \l
    {deployment-mac.html#application-dependencies}{Mac}.

    The procedure of deploying Qt applications is different for the
    various platforms:

    \list
        \o \l{Deploying an Application on Qt/X11}{Qt/X11}
        \o \l{Deploying an Application on Qt/Windows}{Qt/Windows}
        \o \l{Deploying an Application on Qt/Mac}{Qt/Mac}
        \o \l{Deploying Qtopia Core Applications}{Qtopia Core}
    \endlist

    \sa Installation {Window System Specific Notes}
*/

/*!
    \page deployment-x11.html
    \contentspage Deploying Qt Applications

    \title Deploying an Application on Qt/X11
    \ingroup deployment

    Due to the proliferation of Unix systems (commercial Unices, Linux
    distributions, etc.), deployment on Unix is a complex
    topic. Before we start, be aware that programs compiled for one
    Unix flavor will probably not run on a different Unix system. For
    example, unless you use a cross-compiler, you cannot compile your
    application on Irix and distribute it on AIX.

    Contents:

    \tableofcontents

    This documentation will describe how to determine which files you
    should include in your distribution, and how to make sure that the
    application will find them at run-time. We will demonstrate the
    procedures in terms of deploying the \l {tools/plugandpaint}{Plug
    & Paint} application that is provided in Qt's examples directory.

    \section1 Static Linking

    Static linking is often the safest and easiest way to distribute
    an application on Unix since it relieves you from the task of
    distributing the Qt libraries and ensuring that they are located
    in the default search path for libraries on the target system.

    \section2 Building Qt Statically

    To use this approach, you must start by installing a static version
    of the Qt library:

    \code
        cd /path/to/Qt
        ./configure -static -prefix /path/to/Qt <other parameters>
        make sub-src
    \endcode

    We specify the prefix so that we do not overwrite the existing Qt
    installation. The example above only builds the Qt libraries,
    i.e. the examples and Qt Designer will not be built.  When \c make
    is done, you will find the Qt libraries in the \c /path/to/Qt/lib
    directory.

    When linking your application against static Qt libraries, note
    that you might need to add more libraries to the \c LIBS line in
    your project file. For more information, see the \l {Application
    Dependencies} section.

    \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:

    \code
        cd /path/to/Qt/examples/tools/plugandpaint
    \endcode

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

    \code
        make clean
        PATH=/path/to/Qt/bin:$PATH
        export PATH
        qmake -config release
        make
    \endcode

    You probably want to link against the release libraries, and you
    can specify this when invoking \c qmake. Note that we must set the
    path to the static Qt that we just built.

    To check that the application really links statically with Qt, run
    the \c ldd tool (available on most Unices):

    \code
        ldd ./application
    \endcode

    Verify that the Qt libraries are not mentioned in the output.

    Now, provided that everything compiled and linked without any
    errors, we should have a \c plugandpaint file that is ready for
    deployment. One easy way to check that the application really can
    be run stand-alone is to copy it to a machine that doesn't have Qt
    or any Qt applications installed, and run it on that machine.

    Remember that if your application depends on compiler specific
    libraries, these must still be redistributed along with your
    application. For more information, see the \l {Application
    Dependencies} section.

    The \l {tools/plugandpaint}{Plug & Paint} example consists of
    several components: The core application (\l
    {tools/plugandpaint}{Plug & Paint}), and the \l
    {tools/plugandpaintplugins/basictools}{Basic Tools} and \l
    {tools/plugandpaintplugins/extrafilters}{Extra Filters}
    plugins. Since we cannot deploy plugins using the static linking
    approach, the executable 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 shared library approach.

    \section1 Shared Libraries

    We have two challenges when deploying the \l
    {tools/plugandpaint}{Plug & Paint} application using the shared
    libraries approach: The Qt runtime has to be correctly
    redistributed along with the application executable, and the
    plugins have to be installed in the correct location on the target
    system so that the application can find them.

    \section2 Building Qt as a Shared Library

    We assume that you already have installed Qt as a shared library,
    which is the default when installing Qt, in the \c /path/to/Qt
    directory. For more information on how to build Qt, see the \l
    {Installation} documentation.

    \section2 Linking the Application to Qt as a Shared Library

    After ensuring that Qt is built as a shared library, we can build
    the \l {tools/plugandpaint}{Plug & Paint} application. First, we
    must go into the directory that contains the application:

    \code
        cd /path/to/Qt/examples/tools/plugandpaint
    \endcode

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

    \code
        make clean
        qmake -config release
        make
    \endcode

    This builds the core application, the following will build the
    plugins:

    \code
        cd ../plugandpaintplugins
        make clean
        qmake -config release
        make
    \endcode

    If everything compiled and linked without any errors, we will get
    a \c plugandpaint executable and the \c libpnp_basictools.so and
    \c libpnp_extrafilters.so plugin files.

    \section2 Creating the Application Package

    There is no standard package management on Unix, so the method we
    present below is a generic solution. See the documentation for
    your target system for information on how to create a package.

    To deploy the application, we must make sure that we copy the
    relevant Qt libraries (corresponding to the Qt modules used in the
    application) as well as the executable to the same
    directory. Remember that if your application depends on compiler
    specific libraries, these must also be redistributed along with
    your application. For more information, see the \l {Application
    Dependencies} section.

    We'll cover the plugins shortly, but the main issue with shared
    libraries is that you must ensure that the dynamic linker will
    find the Qt libraries. Unless told otherwise, the dynamic linker
    doesn't search the directory where your application resides. There
    are many ways to solve this:

    \list
    \o You can install the Qt libraries in one of the system
       library paths (e.g. \c /usr/lib on most systems).

    \o You can pass a predetermined path to the \c -rpath command-line
       option when linking the application. This will tell the dynamic
       linker to look in this directory when starting your application.

    \o You can write a startup script for your application,
       where you modify the dynamic linker configuration (e.g.
       adding your application's directory to the \c LD_LIBRARY_PATH
       environment variable).
    \endlist

    The disadvantage of the first approach is that the user must have
    super user privileges. The disadvantage of the second approach is
    that the user may not have privileges to install into the
    predetemined path. In either case, the users don't have the option
    of installing to their home directory. We recommend using the
    third approach since it is the most flexible. For example, a \c
    plugandpaint.sh script will look like this:

    \code
        #!/bin/sh
        appname=`basename $0 | sed s,\.sh$,,`
        dirname=`dirname $0`
        if [ "${dirname:0:1}" != "/" ]; then
        dirname=$PWD/$dirname
        fi
        LD_LIBRARY_PATH=$dirname
        export LD_LIBRARY_PATH
        $dirname/$appname $*
    \endcode

    By running this script instead of the executable, you are sure
    that the Qt libraries will be found by the dynamic linker. Note
    that you only have to rename the script to use it with other
    applications.

    When looking for plugins, the application searches in a plugins
    subdirectory inside the directory of the application
    executable. Either you have to manually copy the plugins into the
    \c plugins directory, or you can set the \c DESTDIR in the
    plugins' project files:

    \code
        DESTDIR = /path/to/Qt/plugandpaint/plugins
    \endcode

    An archive distributing all the Qt libraries, and all the plugins,
    required to run the \l {tools/plugandpaint}{Plug & Paint}
    application, would have to include the following files:

    \table 100%
    \header
        \o Component \o {2, 1} File Name
    \row
        \o The executable
        \o {2, 1} \c plugandpaint
    \row
        \o The script to run the executable
        \o {2, 1} \c plugandpaint.sh
    \row
        \o The Basic Tools plugin
        \o {2, 1} \c plugins\libpnp_basictools.so
    \row
        \o The ExtraFilters plugin
        \o {2, 1} \c plugins\libpnp_extrafilters.so
    \row
        \o The Qt Core module
        \o {2, 1} \c libQtCore.so.4
    \row
        \o The Qt GUI module
        \o {2, 1} \c libQtGui.so.4
    \endtable

    On most systems, the extension for shared libraries is \c .so. A
    notable exception is HP-UX, which uses \c .sl.

    Remember that if your application depends on compiler specific
    libraries, these must still be redistributed along with your
    application. For more information, see the \l {Application
    Dependencies} section.

    To verify that the application now can be successfully deployed,
    you can extract this archive on a machine without Qt and without
    any compiler installed, and try to run it, i.e. run the \c
    plugandpaint.sh script.

    An alternative to putting the plugins in the \c plugins
    subdirectory is to add a custom search path when you start your
    application using QApplication::addLibraryPath() or
    QApplication::setLibraryPaths().

    \code
        qApp->addLibraryPath("/some/other/path");
    \endcode

    \section1 Application Dependencies

    \section2 Additional Libraries

    To find out which libraries your application depends on, run the
    \c ldd tool (available on most Unices):

    \code
        ldd ./application
    \endcode

    This will list all the shared library dependencies for your
    application. Depending on configuration, these libraries must be
    redistributed along with your application. In particular, the
    standard C++ library must be redistributed if you're compiling
    your application with a compiler that is binary incompatible with
    the system compiler. When possible, the safest solution is to link
    against these libraries statically.

    You will probably want to link dynamically with the regular X11
    libraries, since some implementations will try to open other
    shared libraries with \c dlopen(), and if this fails, the X11
    library might cause your application to crash.

    It's also worth mentioning that Qt will look for certain X11
    extensions, such as Xinerama and Xrandr, and possibly pull them
    in, including all the libraries that they link against. If you
    can't guarantee the presence of a certain extension, the safest
    approach is to disable it when configuring Qt (e.g. \c {./configure
    -no-xrandr}).

    FontConfig and FreeType are other examples of libraries that
    aren't always available or that aren't always binary
    compatible. As strange as it may sound, some software vendors have
    had success by compiling their software on very old machines and
    have been very careful not to upgrade any of the software running
    on them.

    When linking your application against the static Qt libraries, you
    must explicitly link with the dependent libraries mentioned
    above. Do this by adding them to the \c LIBS variable in your
    project file.

    \section2 Qt Plugins

    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.

    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. As
    mentioned above, using pre-determined paths has certain
    disadvantages, so you need to examine various alternatives to make
    sure that the Qt plugins are found:

    \list

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

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

    \o Using a third party installation utility or the target system's
    package manager to change the hard-coded paths in the QtCore
    library.

    \endlist
*/

/*!
    \page deployment-windows.html
    \contentspage Deploying Qt Applications

    \title Deploying an Application on Qt/Windows
    \ingroup deployment

    This documentation will describe how to determine which files you
    should include in your distribution, and how to make sure that the
    application will find them at run-time. We will demonstrate the
    procedures in terms of deploying the \l {tools/plugandpaint}{Plug
    & Paint} application that is provided in Qt's examples directory.

    Contents:

    \tableofcontents

    \section1 Static Linking

    If you want to keep things simple by only having a few files to
    deploy, i.e. a stand-alone executable with the associated compiler
    specific DLLs, then you must build everything statically.

    \section2 Building Qt Statically

    Before we can build our application we must make sure that Qt is
    built statically. To do this, go to a command prompt and type the
    following:

    \code
        cd C:\path\to\Qt
        configure -static <any other options you need>
    \endcode

    Remember to specify any other options you need, such as data base
    drivers, as arguments to \c configure. Once \c configure has
    finished, type the following:

    \code
        nmake sub-src
    \endcode

    This will build Qt statically. Note that unlike with a dynamic build,
    building Qt statically will result in libraries without version numbers;
    e.g. \c QtCore4.lib will be \c QtCore.lib. Also, we have used \c nmake
    in all the examples, but if you use MinGW you must use
    \c mingw32-make instead.

    \section2 Linking the Application to the Static Version of Qt

    Once Qt has finished building we can build the \l
    {tools/plugandpaint}{Plug & Paint} application. First we must go
    into the directory that contains the application:

    \code
        cd examples\tools\plugandpaint
    \endcode

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

    \code
        nmake clean
        qmake -config release
        nmake
    \endcode

    You probably want to link against the release libraries, and you
    can specify this when invoking \c qmake. Now, provided that
    everything compiled and linked without any errors, we should have
    a \c plugandpaint.exe file that is ready for deployment. One easy
    way to check that the application really can be run stand-alone is
    to copy it to a machine that doesn't have Qt or any Qt
    applications installed, and run it on that machine.

    Remember that if your application depends on compiler specific
    libraries, these must still be redistributed along with your
    application. You can check which libraries your application is
    linking against by using the \c depends tool. For more
    information, see the \l {Application Dependencies} section.

    The \l {tools/plugandpaint}{Plug & Paint} example consists of
    several components: The application itself (\l
    {tools/plugandpaint}{Plug & Paint}), and the \l
    {tools/plugandpaintplugins/basictools}{Basic Tools} and \l
    {tools/plugandpaintplugins/extrafilters}{Extra Filters}
    plugins. Since we cannot deploy plugins using the static linking
    approach, the application we have prepared is incomplete. It will
    run, but the functionality will be disabled due to the missing
    plugins. To deploy plugin-based applications we should use the
    shared library approach.

    \section1 Shared Libraries

    We have two challenges when deploying the \l
    {tools/plugandpaint}{Plug & Paint} application using the shared
    libraries approach: The Qt runtime has to be correctly
    redistributed along with the application executable, and the
    plugins have to be installed in the correct location on the target
    system so that the application can find them.

    \section2 Building Qt as a Shared Library

    We assume that you already have installed Qt as a shared library,
    which is the default when installing Qt, in the \c C:\path\to\Qt
    directory. For more information on how to build Qt, see the \l
    {Installation} documentation.

    \section2 Linking the Application to Qt as a Shared Library

    After ensuring that Qt is built as a shared library, we can build
    the \l {tools/plugandpaint}{Plug & Paint} application. First, we
    must go into the directory that contains the application:

    \code
        cd examples\tools\plugandpaint
    \endcode

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

    \code
        nmake clean
        qmake -config release
        nmake
    \endcode

    This builds the core application, the following will build the
    plugins:

    \code
        cd ..\plugandpaintplugins
        nmake clean
        qmake -config release
        nmake
    \endcode

    If everything compiled and linked without any errors, we will get
    a \c plugandpaint.exe executable and the \c pnp_basictools.dll and
    \c pnp_extrafilters.dll plugin files.

    \section2 Creating the Application Package

    To deploy the application, we must make sure that we copy the
    relevant Qt DLL (corresponding to the Qt modules used in
    the application) as well as the executable to the same directory
    in the \c release subdirectory.

    Remember that if your application depends on compiler specific
    libraries, these must be redistributed along with your
    application. You can check which libraries your application is
    linking against by using the \c depends tool. For more
    information, see the \l {Application Dependencies} section.

    We'll cover the plugins shortly, but first we'll check that the
    application will work in a deployed environment: Either copy the
    executable and the Qt DLLs to a machine that doesn't have Qt
    or any Qt applications installed, or if you want to test on the
    build machine, ensure that the machine doesn't have Qt in its
    environment.

    If the application starts without any problems, then we have
    successfully made a dynamically linked version of the \l
    {tools/plugandpaint}{Plug & Paint} application. But the
    application's functionality will still be missing since we have
    not yet deployed the associated plugins.

    Plugins work differently to normal DLLs, so we can't just
    copy them into the same directory as our application's executable
    as we did with the Qt DLLs.  When looking for plugins, the
    application searches in a \c plugins subdirectory inside the
    directory of the application executable.

    So to make the plugins available to our application, we have to
    create the \c plugins subdirectory and copy over the relevant DLLs:

    \code
        plugins\pnp_basictools.dll
        plugins\pnp_extrafilters.dll
    \endcode

    An archive distributing all the Qt DLLs and application
    specific plugins required to run the \l {tools/plugandpaint}{Plug
    & Paint} application, would have to include the following files:

    \table 100%
    \header
        \o Component \o {2, 1} File Name
    \row
        \o The executable
        \o {2, 1} \c plugandpaint.exe
    \row
        \o The Basic Tools plugin
        \o {2, 1} \c plugins\pnp_basictools.dll
    \row
        \o The ExtraFilters plugin
        \o {2, 1} \c plugins\pnp_extrafilters.dll
    \row
        \o The Qt Core module
        \o {2, 1} \c qtcore4.dll
    \row
        \o The Qt GUI module
        \o {2, 1} \c qtgui4.dll
    \endtable

    In addition, the archive must contain the following compiler
    specific libraries depending on your version of Visual Studio:

    \table 100%
    \header
        \o \o VC++ 6.0 \o VC++ 7.1 (2003) \o VC++ 8.0 (2005)
    \row
        \o The C run-time
        \o \c msvcrt.dll
        \o \c msvcr71.dll
        \o \c msvcr80.dll
    \row
        \o The C++ run-time
        \o \c msvcp60.dll
        \o \c msvcp71.dll
        \o \c msvcp80.dll
    \endtable

    To verify that the application now can be successfully deployed,
    you can extract this archive on a machine without Qt and without
    any compiler installed, and try to run it.

    An alternative to putting the plugins in the plugins subdirectory
    is to add a custom search path when you start your application
    using QApplication::addLibraryPath() or
    QApplication::setLibraryPaths().

    \code
        qApp->addLibraryPath("C:\some\other\path");
    \endcode

    One benefit of using plugins is that they can easily be made
    available to a whole family of applications.

    It's often most convenient to add the path in the application's \c
    main() function, right after the QApplication object is
    created. Once the path is added, the application will search it
    for plugins, in addition to looking in the \c plugins subdirectory
    in the application's own directory. Any number of additional paths
    can be added.

    \section2 Visual Studio 2005

    When deploying an application compiled with Visual Studio 2005
    there are some additional considerations that need to be handled.

    First, we need to copy the manifest file created when linking the
    application. This manifest file contains information about the
    application's dependencies on side-by-side assemblies, such as the
    runtime libraries. The manifest file needs to be copied into the
    same folder as the application executable. You do not need to copy
    the manifest files for shared libraries (DLLs), since they
    are not used. If the shared library has different dependencies than
    the application using it, the manifest file needs to be embedded
    into the DLL binary. In Qt 4.1.3 and later we have the following
    \c CONFIG options for embedding manifests:

    \code
        embed_manifest_dll
        embed_manifest_exe
    \endcode

    To use the options, add

    \code
        CONFIG += embed_manifest_exe
    \endcode

    to your .pro file. The \c embed_manifest_dll option is enabled by default.

    You can find more information about manifest files and side-by-side
    assemblies at the \l {http://msdn.microsoft.com/library/default.asp?url=/library/en-us/sbscs/setup/side_by_side_assemblies_reference.asp}{MSDN website}.

    There are two ways to include the run time libraries: by bundling them
    directly with your application or by installing them on the end-user's
    system.

    To bundle the run time libraries with your application, copy the directory

    \code
        <Visual Studio Install Path>\VC\redist\<Architecture>\Microsoft.VC80.CRT
    \endcode

    into the folder where your executable is, so that you are including a
    \c Microsoft.VC80.CRT directory alongside your application's executable.
    If you are bundling the runtimes and also need to deploy plugins you have
    to remove the manifest from the plugins (embedded as a resource) by
    adding this to the pro file of the plugins you are compiling:

\code
    CONFIG-=embed_manifest_dll
\endcode

    If this is not done, plugins will not load on some systems. 


    To install the run time libraries on the end-user's system, you need to
    include the appropriate Visual C++ Redistributable Package (VCRedist)
    executable with your application and ensure that it is executed when the
    user installs your application.

    For example, on an 32-bit x86-based system, you would include the
    \l{http://www.microsoft.com/downloads/details.aspx?FamilyId=32BC1BEE-A3F9-4C13-9C99-220B62A191EE}{vcredist_x86.exe}
    executable. The \l{http://www.microsoft.com/downloads/details.aspx?familyid=526BF4A7-44E6-4A91-B328-A4594ADB70E5}{vcredist_IA64.exe}
    and \l{http://www.microsoft.com/downloads/details.aspx?familyid=90548130-4468-4BBC-9673-D6ACABD5D13B}{vcredist_x64.exe}
    executables provide the appropriate libraries for the IA64 and 64-bit x86 architectures, respectively.

    \section1 Application Dependencies

    \section2 Additional Libraries

    Depending on configuration, compiler specific libraries must be
    redistributed along with your application. You can check which
    libraries your application is linking against by using the
    \l{Dependency Walker} tool. All you need to do is to run it like
    this:

    \code
        depends <application executable>
    \endcode

    This will provide a list of the libraries that your application
    depends on and other information.

    \image deployment-windows-depends.png

    When looking at the release build of the Plug & Paint executable
    (\c plugandpaint.exe) with the \c depends tool, the tool lists the
    following immediate dependencies to non-system libraries:

    \table 100%
        \header
            \o Qt
            \o VC++ 6.0
            \o VC++ 7.1 (2003)
            \o VC++ 8.0 (2005)
            \o MinGW
        \row
        \o \list
               \o QTCORE4.DLL - The QtCore runtime
               \o QTGUI4.DLL - The QtGui runtime
           \endlist
        \o \list
               \o MSVCRT.DLL - The C runtime
               \o MSVCP60.DLL - The C++ runtime (only when STL is installed)
           \endlist
        \o \list
               \o MSVCR71.DLL - The C runtime
               \o MSVCP71.DLL - The C++ runtime (only when STL is installed)
           \endlist
        \o \list
               \o MSVCR80.DLL - The C runtime
               \o MSVCP80.DLL - The C++ runtime (only when STL is installed)
           \endlist
        \o \list
               \o MINGWM10.DLL - The MinGW run-time
           \endlist
    \endtable

    When looking at the plugin DLLs the exact same dependencies
    are listed.

    \section2 Qt Plugins

    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.

    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 to be a \c plugins subdirectory of
    the Qt installation:

    \code
    C:<path to Qt>\plugins
    \endcode

    Pre-determined paths like this one have certain disadvantages.
    For example, they may not exist on the target machine. For that
    reason you need to examine various alternatives to make sure that
    the Qt plugins are found:

    \list

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

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

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

    \endlist
*/

/*!
    \page deployment-mac.html
    \contentspage Deploying Qt Applications

    \title Deploying an Application on Qt/Mac
    \ingroup deployment

    This documentation will describe how to create a bundle, and how
    to make sure that the application will find the resources it needs
    at run-time. We will demonstrate the procedures in terms of
    deploying the \l {tools/plugandpaint}{Plug & Paint} application
    that is provided in Qt's examples directory.

    \tableofcontents

    \section1 The Bundle

    On the Mac, a GUI application must be built and run from a
    bundle. A bundle is a directory structure that appears as a single
    entity when viewed in the Finder. A bundle for an application
    typcially contains the executable and all the resources it
    needs. See the image below:

    \image deployment-mac-bundlestructure.png

    The bundle provides many advantages to the user. One primary
    advantage is that, since it is a single entity, it allows for
    drag-and-drop installation. As a programmer you can access bundle
    information in your own code. This is specific to Mac OS X and
    beyond the scope of this document. More information about bundles
    is available on \l
    {http://developer.apple.com/documentation/CoreFoundation/Conceptual/CFBundles/index.html}{Apple's Developer Website}.

    A Qt command line application on Mac OS X works similar to a
    command line application on Unix and Windows. You probably don't
    want to run it in a bundle: Add this to your application's .pro:

    \code
        CONFIG-=app_bundle
    \endcode

    This will tell \c qmake not to put the executable inside a
    bundle. Please refer to the \l {Deploying an application on
    Qt/x11} {x11 deployment documentation} for information about how
    to deploy these "bundle-less" applications.

    \section1 Xcode

    We will only concern ourselves with command-line tools here. While
    it is possible to use Xcode for this, Xcode has changed enough
    between each version that it makes it difficult to document it
    perfectly for each version. A future version of this document may
    include more information for using Xcode in the deployment
    process.

    \section1 Static Linking

    If you want to keep things simple by only having a few files to
    deploy, then you must build everything statically.

    \section2 Building Qt Statically

    Start by installing a static version of the Qt library. Remember
    that you will not be able to use plugins and you must build in all
    the image formats, SQL drivers, etc..

    \code
        cd /path/to/Qt
        ./configure -static <other parameters>
        make sub-src
    \endcode

    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:

    \code
        cd /path/to/Qt/examples/tools/plugandpaint
    \endcode

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

    \code
        make clean
        qmake -config release
        make
    \endcode

    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. This doesn't have
    as large an effect if you are using GCC 4, since Qt will then have
    function visibility hints built-in, but if you use GCC 3.3, it
    could make a difference.

    Now, provided that everything compiled and linked without any
    errors, we should have a \c plugandpaint.app bundle that is ready
    for deployment. One easy way to check that the application really
    can be run stand-alone is to copy the bundle to a machine that
    doesn't have Qt or any Qt applications installed, and run the
    application on that machine.

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

    \code
        otool -L plugandpaint.app/Contents/MacOs/plugandpaint
    \endcode

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

    \code
        plugandpaint.app/Contents/MacOS/plugandpaint:
        /System/Library/Frameworks/Carbon.framework/Versions/A/Carbon
                (compatibility version 2.0.0, current version 128.0.0)
        /System/Library/Frameworks/QuickTime.framework/Versions/A/QuickTime
                (compatibility version 1.0.0, current version 10.0.0)
        /usr/lib/libz.1.dylib
                (compatibility version 1.0.0, current version 1.2.3)
        /System/Library/Frameworks/ApplicationServices.framework/Versions/A/ApplicationServices
                (compatibility version 1.0.0, current version 22.0.0)
        /usr/lib/libstdc++.6.dylib
                (compatibility version 7.0.0, current version 7.3.0)
        /usr/lib/libgcc_s.1.dylib
                (compatibility version 1.0.0, current version 1.0.0)
        /usr/lib/libmx.A.dylib
                (compatibility version 1.0.0, current version 92.0.0)
        /usr/lib/libSystem.B.dylib
                (compatibility version 1.0.0, current version 88.0.0)
    \endcode

    For more information, see the \l {Application Dependencies}
    section.

    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 will always choose dynamic over
    static. There are two solutions: Either move your Qt dynamic
    libraries (\c .dylibs) away to another directory while you link
    the application and then move them back, or edit the \c Makefile
    and replace link lines for the Qt libraries with the absolute path
    to the static libraries. For example, replace

    \code
        -lQtGui
    \endcode

    with

    \code
        /where/static/qt/lib/is/libQtGui.a
    \endcode

    The \l {tools/plugandpaint}{Plug & Paint} example consists of
    several components: The core application (\l
    {tools/plugandpaint}{Plug & Paint}), and the \l
    {tools/plugandpaintplugins/basictools}{Basic Tools} and \l
    {tools/plugandpaintplugins/extrafilters}{Extra Filters}
    plugins. Since 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.

    \section1 Frameworks

    We have two challenges when deploying the \l
    {tools/plugandpaint}{Plug & Paint} application using frameworks:
    The Qt runtime has to be correctly redistributed along with the
    application bundle, and the plugins have to be installed in the
    correct location so that the application can find them.

    When distributing Qt with your application using frameworks, you
    have two options: You can either distribute Qt as a private
    framework within your application bundle, or you can distribute Qt
    as a standard framework (alternatively use the Qt frameworks in
    the installed binary). These two approaches are essentially the
    same. The latter option is good if you have many Qt applications
    and you would prefer to save memory. 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.

    \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, see the \l
    Installation documentation.

    When installing, the identification name of the frameworks will
    also be set. The identification name is what the dynamic linker
    (\c dyld) uses to find the libraries for your application.

    \section2 Linking the Application to Qt as Frameworks

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

    \code
        cd /path/to/Qt/examples/tools/plugandpaint
    \endcode

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

    \code
        make clean
        qmake -config release
        make
    \endcode

    This builds the core application, the following will build the
    plugins:

    \code
        cd ../plugandpaintplugins
        make clean
        qmake -config release
        make
    \endcode

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

    \code
        otool -L QtGui.framework/QtGui
    \endcode

    You will get the following output:

    \code
        QtGui.framework/QtGui:
        /path/to/Qt/lib/QtGui.framework/Versions/4.0/QtGui
                (compatibility version 4.0.0, current version 4.0.1)
        /System/Library/Frameworks/Carbon.framework/Versions/A/Carbon
                (compatibility version 2.0.0, current version 128.0.0)
        /System/Library/Frameworks/QuickTime.framework/Versions/A/QuickTime
                (compatibility version 1.0.0, current version 10.0.0)
        /path/to/Qt/QtCore.framework/Versions/4.0/QtCore
                (compatibility version 4.0.0, current version 4.0.1)
        /usr/lib/libz.1.dylib
                (compatibility version 1.0.0, current version 1.2.3)
        /System/Library/Frameworks/ApplicationServices.framework/Versions/A/ApplicationServices
                (compatibility version 1.0.0, current version 22.0.0)
        /usr/lib/libstdc++.6.dylib
                (compatibility version 7.0.0, current version 7.3.0)
        /usr/lib/libgcc_s.1.dylib
                (compatibility version 1.0.0, current version 1.0.0)
        /usr/lib/libmx.A.dylib
                (compatibility version 1.0.0, current version 92.0.0)
        /usr/lib/libSystem.B.dylib
                (compatibility version 1.0.0, current version 88.0.0)
    \endcode

    For the Qt frameworks, the first line (i.e. \c
    {path/to/Qt/lib/QtGui.framework/Versions/4.0/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
    upon location, or store the frameworks in the bundle itself.
    Regardless of which solution you choose, you must make sure that
    the frameworks return the proper identification name for
    themselves, and that the application will look 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.

    \code
        mkdir plugandpaint.app/Contents/Frameworks
        cp -R /path/to/Qt/lib/QtCore.framework
                plugandpaint.app/Contents/Frameworks
        cp -R /path/to/Qt/lib/QtGui.framework
               plugandpaint.app/Contents/Frameworks
    \endcode

    First we create a \c Frameworks directory inside the bundle. This
    follows the Mac OS X application convention. We then copy the
    frameworks into the new directory. Since frameworks contain
    symbolic links, and we want to preserve them, we use the \c -R
    option.

    \code
        install_name_tool -id @executable_path/../Frameworks/QtCore.framework/Versions/4.0/QtCore
               plugandpaint.app/Contents/Frameworks/QtCore.framework/Versions/4.0/QtCore
        install_name_tool -id @executable_path/../Frameworks/QtGui.framework/Versions/4.0/QtGui
               plugandpaint.app/Contents/Frameworks/QtGui.framework/Versions/4.0/QtGui
    \endcode

    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 which
    identification we wish to change.  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 will be located "one directory up and over" in the \c
    Frameworks directory.

    \code
        install_name_tool -change path/to/Qt/lib/QtCore.framework/Versions/4.0/QtCore
                @executable_path/../Frameworks/QtCore.framework/Versions/4.0/QtCore
                plugandpaint.app/Contents/MacOs/plugandpaint
        install_name_tool -change path/to/qt/lib/QtGui.framework/Versions/4.0/QtGui
                @executable_path/../Frameworks/QtGui.framework/Versions/4.0/QtGui
                plugandpaint.app/Contents/MacOs/plugandpaint
    \endcode

    Now, the dynamic linker knows where to look for QtCore and
    QtGui. Then we must make the application aware of the library
    locations as well using \c install_name_tool's \c -change mode.
    This basically comes down to string replacement, to match the
    identification names that we set for the frameworks.

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

    \code
        install_name_tool -change path/to/Qt/lib/QtCore.framework/Versions/4.0/QtCore
                @executable_path/../Frameworks/QtCore.framework/Versions/4.0/QtCore
                plugandpaint.app/Contents/Frameworks/QtGui.framework/Versions/4.0/QtGui
    \endcode

    After all this we can run \c otool again and see that the
    application will look in the right locations.

    Of course, the thing that makes the \l {tools/plugandpaint}{Plug &
    Paint} example interesting are its plugins. The basic steps we
    need to follow with plugins are:

    \list
        \o Put the plugins inside the bundle
        \o Make sure that the plugins use the correct library using the
           \c install_name_tool
        \o Make sure that the application knows where to get the plugins
    \endlist

    While we can put the plugins anywhere we want in the bundle, the
    best location to put them is under Contents/Plugins. When we built
    the Plug & Paint plugins, the \c DESTDIR variable in their \c .pro
    file put the plugins' \c .dylib files in a \c plugins subdirectory
    in the \c plugandpaint directory. So, in this example, all we need
    to do is move this directory:

    \code
        mv plugins plugandpaint.app/Contents
    \endcode

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

    \code
        libpnp_basictools.dylib:
        libpnp_basictools.dylib
               (compatibility version 0.0.0, current version 0.0.0)
        /path/to/Qt/lib/QtGui.framework/Versions/4.0/QtGui
               (compatibility version 4.0.0, current version 4.0.1)
        /System/Library/Frameworks/Carbon.framework/Versions/A/Carbon
               (compatibility version 2.0.0, current version 128.0.0)
        /System/Library/Frameworks/QuickTime.framework/Versions/A/QuickTime
               (compatibility version 1.0.0, current version 10.0.0)
        /path/to/Qt/lib/QtCore.framework/Versions/4.0/QtCore
               (compatibility version 4.0.0, current version 4.0.1)
        /usr/lib/libz.1.dylib
               (compatibility version 1.0.0, current version 1.2.3)
        /System/Library/Frameworks/ApplicationServices.framework/Versions/A/ApplicationServices
               (compatibility version 1.0.0, current version 22.0.0)
        /usr/lib/libstdc++.6.dylib
               (compatibility version 7.0.0, current version 7.3.0)
        /usr/lib/libgcc_s.1.dylib
               (compatibility version 1.0.0, current version 1.0.0)
        /usr/lib/libmx.A.dylib
               (compatibility version 1.0.0, current version 92.0.0)
        /usr/lib/libSystem.B.dylib
               (compatibility version 1.0.0, current version 88.0.0)
    \endcode

    Then we can see that the plugin links to the Qt frameworks it was
    built against. Since 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:

    \code
        install_name_tool -change /path/to/Qt/lib/QtCore.framework/Versions/4.0/QtCore
                @executable_path/../Frameworks/QtCore.framework/Versions/4.0/QtCore
                plugandpaint.app/Contents/plugins/libpnp_basictools.dylib
        install_name_tool -change /path/to/Qt/lib/QtGui.framework/Versions/4.0/QtGui
                @executable_path/../Frameworks/QtGui.framework/Versions/4.0/QtGui
                plugandpaint.app/Contents/plugins/libpnp_basictools.dylib
    \endcode


    We must also modify the code in \c
    tools/plugandpaint/mainwindow.cpp to \l {QDir::cdUp()}{cdUp()} one
    directory since the plugins live in the bundle. Add the following
    code to the \c mainwindow.cpp file:

    \code
        #elif defined(Q_OS_MAC)
        if (pluginsDir.dirName() == "MacOS") {
            pluginsDir.cdUp();
        }
        #endif
    \endcode

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

    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 approach from above.

    Copy Qt's image format plugins into the bundle:

    \code
        cp -R /path/to/Qt/plugins/imageformats
                pluginandpaint.app/Contents/plugins
    \endcode

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

    \code
        install_name_tool -change /path/to/Qt/lib/QtGui.framework/Versions/4.0/QtGui
                @executable_path/../Frameworks/QtGui.framework/Versions/4.0/QtGui
                plugandpaint.app/Contents/plugins/imageformats/libqjpeg.dylib
        install_name_tool -change /path/to/Qt/lib/QtCore.framework/Versions/4.0/QtCore
                @executable_path/../Frameworks/QtCore.framework/Versions/4.0/QtCore
                plugandpaint.app/Contents/plugins/imageformats/libqjpeg.dylib
    \endcode

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

    \code
        QDir dir(QApplication::applicationDirPath());
        dir.cdUp();
        dir.cd("plugins");
        QApplication::setLibraryPaths(QStringList(dir.absolutePath()));
    \endcode

    First, we tell the application to only look for plugins in this
    directory. In our case, this is what we want since we only want to
    look for the 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 When deploying plugins, and thus make changes to the
    source code, the default identification names are reset when
    rebuilding the application, and you must repeat the process of
    making your application link to the Qt frameworks in the bundle
    using \c install_name_tool.

    Now you should be able to move the application to another Mac OS X
    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 than in 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. Apple provides a fair bit of information about how to
    do this and instead of repeating it here, we recommend that you
    consult their \l {
    http://developer.apple.com/documentation/DeveloperTools/Conceptual/SoftwareDistribution/SoftwareDistribution.html
    }{software distribution} documentation.

    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 Mac OS X users will enjoy.

    \section1 Application Dependencies

    \section2 Qt Plugins

    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.

    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. For that reason you need
    to examine various alternatives to make sure that the Qt plugins
    are found:

    \list

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

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

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

    \endlist

    \section2 Additional Libraries

    You can check which libraries your application is linking against
    by using the \c otool tool. To use \c otool, all you need to do is
    to run it like this:

    \code
        otool -L MyApp.app/Contents/MacOS/MyApp
    \endcode

    Unlike the deployment processes on \l {Deploying an Application on
    Qt/X11}{X11} and \l {Deploying an Application on
    Qt/Windows}{Windows}, compiler specific libraries rarely have to
    be redistributed along with your application. But since Qt can be
    configured, built, and installed in several ways on Mac OS X,
    there are also several ways to deploy applications. Typically your
    goals help determine how you are going to deploy the
    application. The last sections describe a couple of things to keep
    in mind when you are deploying your application.

    \section2 Mac OS X Version Dependencies

    Qt 4.2 has been designed to be built and deployed on Mac OS X 10.3
    up until the current version as of this writing, Mac OS X 10.4 and
    all their minor releases. Qt acheives this by using "weak
    linking." This means that Qt tests if a function added in newer
    versions of Mac OS X is available on the computer it is running on
    before it uses it. This results in getting access to newer
    features when running on newer versions of OS X while still
    remaining compatible on older versions.

    For more information about cross development issues on Mac OS X,
    see \l
    {http://developer.apple.com/documentation/DeveloperTools/Conceptual/cross_development/index.html}{Apple's Developer Website}.

    Since the linker is set to be compatible with all OS X version, you have to
    change the \c MACOSX_DEPLOYMENT_TARGET environment variable to get weak
    linking to work for your application. You can add:

    \code
    QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.3
    \endcode

    to your .pro file and qmake will take care of this for you.

    However, there is a bit of a wrinkle to keep in mind when your are
    deploying. Mac OS X 10.4 ("Tiger") ships GCC 4.0 as its default
    compiler. This is also the GCC compiler we use for building the
    binary Qt package. If you use GCC 4.0 to build your application,
    it will link against a dynamic libstdc++ that is only available on
    Mac OS X 10.4 and Mac OS X 10.3.9.  The application will refuse to
    run on older versions of the operating system.

    For more information about C++ runtime environment, see \l
    {http://developer.apple.com/documentation/DeveloperTools/Conceptual/CppRuntimeEnv/index.html}{Apple's Developer Website}

    If you want to deploy to versions of Mac OS X earlier than 10.3.9,
    you must build with GCC 3.3 which is the default on Mac OS X
    10.3. GCC 3.3 is also available on the Mac OS X 10.4 "Xcode Tools"
    CD and as a download for earlier versions of Mac OS X from Apple
    (\l {https://connect.apple.com/}{connect.apple.com}). You can use
    Apple's \c gcc_select(1) command line tool to switch the default
    complier on your system.

    \section2 Architecture Dependencies

    The Qt/Mac libraries, tools, and examples can be built "universal"
    (i.e. they run natively on both Intel and PowerPC machines).  This
    is accomplished by passing \c -universal on the \c configure line
    of the source package, and requires that you use GCC 4.0.x. On
    PowerPC hardware you will need to pass the universal SDK as a
    command line argument to the Qt configure command. For example:

    \code
         ./configure (other arguments) -universal -sdk /Developer/SDKs/MacOSX10.4u.sdk
    \endcode

    From 4.1.1 the Qt binary package is already universal.

    If you want to create a binary that runs on older versions of
    PowerPC and x86, it is possible to build Qt for the PowerPC using
    GCC 3.3, and for x86 one using GCC 4.0, and use Apple's \c lipo(1)
    tool to stitch them together. This is beyond the scope of this
    document and is not something we have tried, but Apple documents
    it on their \l
    {http://developer.apple.com/documentation}{developer website}.

    Once you have a universal Qt, \a qmake will generate makefiles
    that will build for its host architecture by default. If you want
    to build for a specific architecture, you can control this with
    the \c CONFIG line in your \c .pro file. Use \c CONFIG+=ppc for
    PowerPC, and \c CONFIG+=x86 for x86. If you desire both, simply
    add both to the \c CONFIG line. PowerPC users also need an
    SDK. For example:

    \code
        QMAKE_MAC_SDK=/Developer/SDKs/MacOSX10.4u.sdk
        CONFIG+=x86 ppc
    \endcode

    Besides \c lipo, you can also check your binaries with the \c file(1)
    command line tool or the Finder.
*/
