qt-creator/doc/qtcreator-faq.qdoc

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**
** This file is part of Qt Creator
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** Copyright (c) 2011 Nokia Corporation and/or its subsidiary(-ies).
**
** Contact: Nokia Corporation (info@qt.nokia.com)
**
**
** GNU Free Documentation License
**
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of this
** file.
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** If you have questions regarding the use of this file, please contact
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****************************************************************************/

/*!
    \contentspage index.html
    \previouspage creator-keyboard-shortcuts.html
    \page creator-faq.html
    \nextpage creator-tips.html

    \title FAQ

    This section contains answers to some frequently asked questions about Qt
    Creator. You might also find answers to your questions in the
    \l{Known Issues} and \l{Tips and Tricks} sections, or the Troubleshooting
    sections for a special area, such as
    \l{Troubleshooting Debugger}{debugging}.

    \section1 General Questions

    \bold {How do I reset all Qt Creator settings?}

    Qt Creator creates two files and a directory:

    \list

        \o  QtCreator.db

        \o  QtCreator.ini

        \o  qtcreator

    \endlist

    The location depends on the platform. On Linux, Unix, and Mac OS, the files
    are located in \c{~/.config/Nokia}.

    On Windows XP, the files are located in
    \c{<drive>:\Documents and Settings\<username>\Application Data\Nokia}, and
    on Windows Vista and Windows 7 in
    \c {<drive>:\Users\<username>\AppData\Roaming\Nokia}.
    For all versions, try the path \c{APPDATA\Nokia}.

    \bold {Qt Creator comes with MinGW, should I use this version with Qt?}

    Use the version that was built against the Qt version.

    \bold {Qt Creator does not find a helper application, such as Git or a
    compiler. What should I do?}

    Make sure that the application is in your system PATH when starting Qt
    Creator. Also select \gui {Tools > Options} to check the settings specified
    for the application. Many plugins specify either the path to the tool they
    need or the environment they run in.

    This is especially relevant for the Mac OS where \c {/usr/local/bin} might
    not be in the path when Qt Creator is started.

    \bold {How do I change the interface language for Qt Creator?}

    Qt Creator has been localized into several languages. If the system
    language is one of the supported languages, it is automatically selected.
    To change the language, select \gui {Tools > Options > Environment} and
    select a language in the \gui Language field. The change takes effect after
    you restart Qt Creator.

    \bold {Has a reported issue been addressed?}

    You can look up any issue in the
    \l{http://bugreports.qt.nokia.com/}{Qt bug tracker}.

    \section1 Qt Designer Integration Questions

    \bold {Why are custom widgets not loaded in Design mode even though it
    works in standalone Qt Designer?}

    Qt Designer fetches plugins from standard locations and loads the plugins
    that match its build key. The locations are different for standalone and
    integrated Qt Designer.

    For more information, see \l{Adding Qt Designer Plugins}.

    \section1 Help Questions

    \bold {The Qt API Reference Documentation is missing and context help does
    not find topics. What can I do?}

    Qt Creator comes fully integrated with Qt documentation and examples using
    the Qt Help plugin. The integrated Qt Reference Documentation is available
    for Qt 4.4 and later. Qt Creator, \QSDK, and other Qt deliverables contain
    documentation as .qch files. All the documentation is accessible in the
    \gui Help mode.

    To view the documentation that is available and to add documentation,
    select \gui {Tools > Options... > Help > Documentation}. For more
    information, see \l{Adding External Documentation}.

    \section1 Debugger Questions

    For information on troubleshooting debugger, see
    \l{Troubleshooting Debugger}.

    \bold {If I have a choice of GDB versions, which should I use?}

    On Linux and Windows, use the Python-enabled GDB versions that are
    installed when you install Qt Creator and Qt SDK. On Mac OS X, use the GDB
    provided with Xcode. For a custom target, you can build your own
    Python-enabled GDB. Follow the instructions in
    \l{http://developer.qt.nokia.com/wiki/QtCreatorBuildGdb}{Building GDB}.

    You must use at least Python version 2.5, but we recommend that you use
    version 2.6.

    For more information on setting up debugger, see \l{Setting Up Debugger}.

    \section1 Code Editor Questions

    \bold {How can I get code-completion to work on the standard headers and
    phonon?}

    Install a build from March 31, 2009, or later.

    \section1 Compiler Questions

    \bold {How can I make use of my multi-core CPU with Qt Creator?}

    On Linux and Mac OS X, go to \gui Project mode, select your configuration
    in the \gui {Build Settings}, locate the \gui {Build Steps}, and add the
    following value, where \c{<num>} is the amount of cores in your CPU:
    \c{-j <num>}

    On Windows, nmake does not support the \c{-j} parameter. Instead, we
    provide a drop-in replacement called jom. You can download a precompiled
    version of jom from \l{ftp://ftp.qt.nokia.com/jom/}{Qt FTP server}.
    Put jom.exe in a location in the %PATH%. Go to the \gui {Build Settings}
    and set jom.exe as the make command.

    \note: Unlike GNU make, jom automatically detects your cores and spawns as
    many parallel processes as your CPU has cores. You can override this
    behavior by using the \c{-j} parameter as described above.

    \section1 Qt SDK Questions

    \bold {I cannot use QSslSocket with the SDK. What should I do?}

    The Qt build in the SDK is built with QT_NO_OPENSSL defined. Rebuilding it
     is possible. For more information, see
     \l{http://www.qtcentre.org/forum/f-qt-programming-2/t-qssl-19222-post94842.html}.

    \bold {Which development packages from the distribution are needed on
    Ubuntu or Debian?}

    \code
    sudo apt-get install libglib2.0-dev libSM-dev libxrender-dev libfontconfig1-dev libxext-dev
    \endcode

    If you use QtOpenGL, you also need:

    \code
    sudo apt-get install libgl-dev libglu-dev
    \endcode

    \section1 Platform Releated Questions

    \bold {Where is application output shown in Qt Creator?}

    \bold {On Unix (Linux and Mac OS):} \c qDebug() and related functions use
    the standard output and error output. When you run or debug the
    application, you can view the output in the \gui{Application Output} pane.

    For console applications that require input, select \gui {Projects > Run
    Settings > Run in terminal}.

    \bold {On Windows:} Output is displayed differently for \e{console
    applications} and \e{GUI applications}.

    The setting \c {CONFIG += console} in the .pro file specifies that the
    application is built as a console application using some other runtime.
    When you run a console application, you can view the output in the console
    window of the calling application. If the
    calling application is a GUI application (for example, a release-built
    version of Qt Creator), a new console window is opened.  For this
    type of application, \c qDebug() and related functions use standard output
    and error output.

    We recommend that you select \gui {Projects > Run Settings > Run in
    terminal} for console applications.

    For GUI applications, \c qDebug() and related functions use the Windows API
    function \c OutputDebugString(). The output is displayed in the
    \gui{Application Output} pane. However, only one output pane tab may be
    open at a time or the output is not displayed correctly. You can use an
    external debug output viewer, such as the
    \l{http://technet.microsoft.com/en-us/sysinternals/bb896647}{DebugView for Windows}
    to display output from GUI applications.

    \bold {On Symbian OS}: \c qDebug() and related functions use the native
    \c RDebug::Print functionality.

    When you use the Symbian emulator on Windows, the output is redirected to
    standard debug output. To view it, you can use a Windows debug output
    viewer, such as the DebugView for Windows.

    On devices, the \c RDebug output is intercepted by \e CODA or \e {App TRK}
    and then propagated to Qt Creator, which displays it in the
    \gui {Application Output} pane.

    Symbian OS provides no support for differentiating between standard output
    and error output.

    \section1 Questions about New Features

    \bold {Will a requested feature be implemented?}

    If it is a scheduled feature, you can see this in the task tracker. If a
    feature already has been implemented, it is mentioned in the
    \l{http://qt.gitorious.org/qt-creator/qt-creator/trees/master/dist}{changes file}
    for the upcoming release.

    \bold {Why does Qt Creator not use tabs for editors?}

    This question comes up from time to time, so we have considered it
    carefully. Here are our main reasons for not using tabs:

    \list

        \o  Tabs do not scale. They work fine if you have 5 to 6 editors open,
            they become cumbersome with 10, and if you need more horizontal
            space than the tab bar, the interface does not work at all.

        \o  Tabs do not adapt to your working set.

        \o  The common solution is to give the user the ability to reorder
            tabs. Now user has to manage tabs instead of writing code.

        \o  Tabs force you to limit the amount of open editors, because
            otherwise you get confused.

    \endlist

    Consider the following use case: \e {Developers want to switch editors.}

    In fact, developers do not want to switch editors, but might have to do so
    to accomplish their tasks. We need to figure out what the tasks are to
    provide developers with better ways to navigate while performing the tasks.

    One common factor in many use cases is switching editors while working on a
    set of open files. While working on files A and B, users sometimes need to
    look at file C. They can press \key Ctrl+Tab to move between the files and
    have the files open in the correct editor according to file type. The list
    is sorted by last used.

    Typically, users also work on multiple classes or functions that are
    related, even though they are defined or declared in different files.
    Qt Creator provides two shortcuts for that: \key F2 to follow the symbol
    and \key Ctrl+Shift+U to find usages.

    In addition, developers can:

    \list

        \o  Press \key F4 to switch between header and source.

        \o  Press \key Alt+Left to move backwards in the navigation history.

        \o  Use the locator (Ctrl+K) to simply tell Qt Creator where to go.

    \endlist

    The locator can be used to open files, but opening files is also just a
    step on the way to accomplish a task. For example, consider the following
    use case: \e {Fix AMethod in SomeClass which comes from
    someclass.cpp/someclass.h}.

    With a tabbed user interface, developers would search for someclass.cpp in
    the tab bar, and then search for \c {::AMethod}, only to find out that the
    method is not located in that file. They would then search for someclass.h
    in the tab bar, find our that the function is inline, fix the problem, and
    forget where they came from.

    With Qt Creator, developers can type \c {Ctrl+K m AMet} to find the method.
    Typically, they only need to type 3 to 4 characters of the method name.
    They can then fix the problem and press \key Alt+Back to go back to where
    they were.

    Other locator filters include \c c for classes, \c : for all symbols, and
    (thanks to a community contribution) \c . for symbols in the current file.

*/