Qt 5.6.2 is a bug-fix release. It maintains both forward and backward
compatibility (source and binary) with Qt 5.6.0.

For more details, refer to the online documentation included in this
distribution. The documentation is also available online:

  http://doc.qt.io/qt-5/index.html

The Qt version 5.6 series is binary compatible with the 5.5.x series.
Applications compiled for 5.5 will continue to run with 5.6.

Some of the changes listed in this file include issue tracking numbers
corresponding to tasks in the Qt Bug Tracker:

  https://bugreports.qt.io/

Each of these identifiers can be entered in the bug tracker to obtain more
information about a particular change.

******************************************************************************
*                     Important Behavior Changes                             *
******************************************************************************

 - [QTBUG-45031] The NSURLConnection backend of QNetworkAccessManager has
   been removed, since SecureTransport is the default SSL backend on iOS
   and is enabled by default. This means that building with -no-openssl
   -no-securetransport will no longer provide SSL capabilities on iOS.

 - QUrl::resolved() no longer treats a URL with a scheme as a relative URL
   if it matches this URL's scheme. For now it still treats "file:name.txt"
   as relative for compatibility, but be warned that in Qt 5.8 it will no
   longer consider those to be relative. Both isRelative() and RFC 3986 say
   that such URLs are not relative, so starting from Qt 5.8, resolved() will
   return them as is.

 - [QTBUG-47815] QDateTime now uses QLocale to get the "AM" and "PM" strings
   when parsing times, instead of strings obtained from the loaded
   translations.

******************************************************************************
*                                Library                                     *
******************************************************************************

General
-------

 - [QTBUG-45291] Qt headers are now gcc -Wzero-as-null-pointer-constant clean.

QtCore
------

 - Optimized toLatin1()/toUtf8() called on a QStringBuilder expression.
 - [QTBUG-18729][QTBUG-32457] Fixed a bug that caused Windows to show
   dialogs prompting the user to insert media when certain operations were
   made with Qt I/O classes, particularly QStorageInfo::mountedVolumes().

 - QCommandLineParser:
   * The methods that exit() the application will now call cleanup routines
     registered with qAddPostRoutine.

 - QDataStream:
   * Fixed compatibility of QTime serialization with Qt 3.

 - QDebug:
   * Fixed streaming of QChars.

 - QJsonObject:
   * Optimized equality operator.

 - QJsonValue:
   * Fixed use-after-free in assignment operator.

 - QLockFile:
   * Fixed permissions on lock files on Unix to allow for adjustments via
     umask.
   * [QTBUG-53392] Improved the robustness of detecting stale lock files on
     Windows.

 - QMutex:
   * [QTBUG-54831] Fixed a bug that caused some applications to crash on
     exit, depending on the order of creation of certain statics inside Qt.

 - QObject:
   * Fixed a crash when connecting a signal to a lambda or functor while
     using Qt::UniqueConnection (note: the connection is still not unique).

 - QStringListModel:
   * Fixed dataChanged()'s 'roles' parameter to always contain both
     Qt::EditRole and Qt::DisplayRole.

 - QTemporaryFile:
   * [QTBUG-54810] Fixed a bug that caused QTemporaryFile to fail when the
     file name contained non-ASCII characters, on Windows.

 - QTimeZone:
   * [QTBUG-53071] Fixed a bug that caused QTimeZone to mis-parse time zones
     whose names were not simple letter and digit combinations.

 - QUrl:
   * Made QUrl stricter in what it accepts for schemes, to comply with the
     relevant standards. QUrl will no longer accept schemes starting with a
     plus (+), a dash (-) or a dot (.).

 - QVariant:
   * [QTBUG-53384] Fixed QVariant::canConvert and conversion from integer
     types to enumeration types.
   * [QTBUG-54893] Fixed a bug that caused QVariants not to compare properly
     if they contained QStringLists.

 - QVector:
   * [QTBUG-51758] Fixed a bug that would cause QVector to crash if one
     called reserve(0).

 - QXmlStreamReader:
   * Fixed a bug in the XML parser that prevented to load XML that
     contained invalid characters for XML 1.0.

 - QXmlStreamWriter:
   * Fixed a bug that prevented the generation of valid XML files when
     using encoding with 8 bit per character but not ASCII compatible.
     QXMLStreamWriter generated XML markup using always ASCII in this case.

QtGui
-----

 - Fixed UBSan errors in
   * QColor
   * QGrayRaster
   * QRasterizer

 - Removed a total of 1610 relocations from the library.

 - QGuiApplication:
   * [QTBUG-51703] Fixed a bug that would cause QGuiApplication::sync() to
     be left undefined for Qt builds without session management support.

 - QIconLoaderEngine:
   * Fixed theme lookup for scalable entries.

 - Text:
   * [QTBUG-42033] Fixed bug where a QTextLayout with
     ShowLineAndParagraphSeparators would modify the layout's input string.
   * [QTBUG-49452] Fixed a performance regression in Freetype engine that
     was introduced in Qt 5.5.
   * [QTBUG-54180] Fixed performance regression when rapidly switching
     between a large set of fonts.

 - Windows:
   * [QTBUG-54494] Fixed stretch when combined with either no or vertical
     hinting preference or a device pixel ratio different from 1.
   * [QTBUG-51024] Fixed height of text bounding box when using no or
     vertical hinting preference, or when the device pixel ratio is
     different from 1.

QtNetwork
---------

 - QAuthenticator:
   * [QTBUG-53338] Fixed crash when comparing an initialized QAuthenticator
     with an uninitialized QAuthenticator.

QtSql
-----

 - [QTBUG-53969][QTBUG-53237] Fixed QSqlQuery::prepare value truncation
   error when using UNSIGNED values in a MySQL database.

QtWidgets
---------

 - Fixed UBSan/Coverity errors in:
   * QAbstractItemView
   * QDataWidgetMapper
   * QTreeWidget
   * QWidgetLineControl

 - Removed a total of 167 relocations from the library.

 - QAbstractItemDelegate:
   * [QTBUG-16469] Show localized detailed tooltips and "What's this?"
     texts.

- QAbstractItemView:
   * [QTBUG-53541] Fixed a bug involving drawing the drop indicator
     where it shouldn't be drawn.
   * Fixed a bug in setSelectionModel() which could lead to model indexes
     from a different model be reused on a new model.

 - QAbstractSpinBox:
   * [QTBUG-55249] Fixed a bug related to first key press.

 - QColorDialog:
   * Fixed ignored alpha channel in getRgb().

 - QComboBox:
   * [QTBUG-54191] Fixed a crash on setEditable(false) called from
     editTextChanged().

 - QCompleter:
   * [QTBUG-54642] Fixed wrong completion role after a QFileSystemModel
     has been used.

 - QDesktopWidget:
   * [QTBUG-52101] Fixed tracking of QScreens.
   * [QTBUG-52606] Fixed a bug related to DPI-scaling in screenNumber().

 - QDialog:
   * [QTBUG-52735] Fixed a bug involving moves between screens with
     different DPI-scaling factors.

 - QDockWidget:
   * [QTBUG-52107][QTBUG-53754] Fixed bugs related to floating group tab
     window title.
   * [QTBUG-52108] A QDockWidgetGroupWindow can now be dragged into one of
     its QDockWidgets.
   * [QTBUG-53808] Fixed a bug that caused an undocked dock widget to lose
     its decoration.
   * [QTBUG-54185] Unbroke drag-and-drop.

 - QGraphicsProxyWidget:
   * [QTBUG-55112] Fixed a bug that caused the widget to receive events
     during construction.

 - QLineEdit:
   * [QTBUG-49374] Fixed icons being too small on a High DPI screen
     without scaling.
   * [QTBUG-52796] Fixed QKeySequence::MoveToStartOfLine shortcut
     being ignored.
   * [QTBUG-54425] Fixed missing clear button on macOS.

 - QMainWindow:
   * [QTBUG-50491] Fixed a bug related to restoring dock widgets with
     GroupedDragging.
   * [QTBUG-52108] Fixed a bug related to context menus in the presence of
     floating tabs.

 - QMenu:
   * [QTBUG-53054] Submenus can now be opened on left mouse button
     press, too.

 - QMenuBar:
   * [QTBUG-53205] Fixed bugs (incl. crashes) involving reparented
     menu bars.

 - QOpenGLWidget:
   * [QTBUG-50818][QTBUG-51815][QTBUG-54241][QTBUG-52419] Fixed several
     repainting bugs and other drawing artifacts.

 - QSideBar:
   * Fixed a nullptr dereference on platforms that do not support
     QFileSystemWatcher.

 - QSystemTrayIcon:
   * [QTBUG-53591] Use large icon for balloon message on Windows systems.

 - QTabBar:
   * Fixed a performance problem involving font metrics.

 - QTreeView:
   * [QTBUG-52793] Fixed a key navigation bug when the columns were
     reordered.

- QTreeWidget:
   * [QTBUG-50207] Now handles device pixel ratio in animations correctly.

- QWidget:
   * [QTBUG-39887] Restored documented behavior for the
     WA_X11NetWmWindowType* attributes.
   * [QTBUG-41135][QTBUG-50030][QTBUG-50136][QTBUG-52507] Fixed
     mapTo/FromGlobal() in case of widget hierarchies embedded into
     QGraphicsView with transformations.
   * [QTBUG-45484] Fixed setWindowRole().
   * [QTBUG-50796] Reduced paint-events when resizing native widgets.
   * [QTBUG-52123] Fixed a bug by which opaque texture-based widgets
     were not always shown.
   * [QTBUG-53515] Added a workaround for render-to-texture widgets in
     fullscreen windows.
   * [QTBUG-54734] Worked around an issue with translucent GL windows
     on Windows.
   * [QTBUG-54906] Fixed a bug relaed to fullscreen handling on Windows.

 - Styles:
   * Fixed several cases of QStyleOptions being created with null
     version.
   * [QTBUG-51266] Fixed painting of small progress bars on Vista+.
   * [QTBUG-54630] Fixed a crash in QMacStyle::styleHint().
   * [QTBUG-49374] The Windows style now takes the monitor's differing
     logical DPI into account when calculating native metrics.

******************************************************************************
*                     Platform-specific Changes                              *
******************************************************************************

Android
-------

 - [QTBUG-50724] Added support for clang compiler.
 - [QTBUG-53511] Fixed CJK font resolution on Android 7.

BSDs
----

 - The freebsd-g++ mkspec was moved back and no longer requires the
   "unsupported/" prefix, matching the FreeBSD ports tree, as FreeBSD 9.3
   still defaults to using GCC. Users of GCC that did not previously use
   the ports patch will need to adapt their build scripts and drop the
   "unsupported/" prefix.
 - Fixed a number of compilation issues on FreeBSD, NetBSD and OpenBSD. Qt
   should now build out-of-the-box (no patches needed) on those systems.

Linux
-----

 - [QTBUG-54733] It is now possible to opt out from installing signal
   handlers when running with eglfs and linuxfb by setting the
   QT_QPA_NO_SIGNAL_HANDLER environment variable to a non-zero value.
 - Fixed the value of the 'defined' field in ATSPI GetAttributeValue
   results.

macOS
-----

 - [QTBUG-48953] Pasting text from Qt applications to Apple Mail now works.
 - [QTBUG-48953] “text/vcard” is now required as the mime type when
   placing vCards on the clipboard.
 - OS X => macOS rename in Q_OS_ macros/docs, qmake scopes,
   file selectors, etc.
 - Add new QSysInfo values and MAC_OS_X / __MAC_ / __IPHONE_ values for
   macOS 10.12 and iOS 9.1 through 10.0.
 - Update prettyProductName with new macOS "Sierra" codename.

Windows
-------

 - Fixed a new[]/delete mismatch in Windows tablet support.

****************************************************************************
*                                Tools                                     *
****************************************************************************

moc
---

 - [QTBUG-53441] Fixed crash on file ending with a backslash followed by
   carriage return

configure & build system
------------------------

 - [QTBUG-35886][QTBUG-51417] Fixed Fontconfig vs. system FreeType
   configuration.
 - [QTBUG-43784][X11] Fixed detection of GLX with -qt-xcb.
 - [QTBUG-52951] Fixed dynamic library support detection for platforms
   without libdl.
 - [QTBUG-53038] Fixed running of configure tests outside qtbase when
   cross compiling on Windows (for example for Android).
 - [QTBUG-53312] The flags supplied by the configure -D/-I/-L/-l options
   are now applied after Qt's own flags. This helps in some cases when
   the provided paths contain files which conflict with the Qt build.
 - [QTBUG-55011][Unix] Fixed -no-pkg-config being ignored by some
   configure tests, which led to build failures later on.
 - Fixed configure tests outside qtbase when $MAKEFLAGS contains the
   -i flag.
 - [Android] Some unused plugins are not built anymore.
 - [MinGW] Added support for -separate-debug-info.
 - [Unix] Added configure -no-opengles3 option.
 - [Unix] Fixed MySQL detection/use on RHEL 6.6.

qmake
-----

 - [QTBUG-41830] Fixed nested custom functions inheriting their callers'
   arguments.
 - [QTBUG-53895][MSVC] Started using separate PDB files for compiling
   and linking.
 - [QTBUG-54036][Darwin] Fixed installation of debug symbols.
 - [QTBUG-54550] Fixed access to freed memory in $$absolute_path().
 - [QTBUG-55183][nmake] _WINDLL is now automatically defined when building
   a DLL, consistently with Visual Studio.
 - [QTBUG-55649][QTBUG-55915][Xcode] Fixed support for Xcode 8.
 - Fixed several cases where the error() function would not abort qmake.
 - Interrupting a command run via system() will now abort qmake as well.
 - The packagesExist() function will now warn when used when Qt was
   configured with -no-pkg-config.
 - [Android] The default compiler flags were adjusted to match newer
   NDK versions.