Qt 5.9 introduces many new features and improvements as well as bugfixes
over the 5.8.x series. 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 5.9 series is binary compatible with the 5.8.x series.
Applications compiled for 5.8 will continue to run with 5.9.

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-48658][QTBUG-56306] The linuxfb and bsdfb platform plugins now
   follow the behavior of eglfs by making the first window fullscreen. This
   provides consistency and avoids applications having to make their
   windows match the screen size manually. The new behavior can be disabled
   by setting the environment variable QT_QPA_FB_FORCE_FULLSCREEN=0.
 - [QTBUG-59391] A QVariant containing a std::nullptr_t is now streamable
   to/from QDataStream.
 - Whitespace inside identifiers in logging rule files is not ignored
   anymore. That is, "[my category]" and "[mycategory]" are now two different
   categories.
 - [QTBUG-59849] QSysInfo::productType() and QFileSelector behavior on
   macOS was restored to match what Qt used to return in version 5.7.0 and
   earlier. The behavior found in Qt 5.6.2, 5.7.1 and 5.8.0 is removed.
 - [QTBUG-60771] Reverted a change that caused Qt 5.6 through 5.8 not to
   connect to QSystemSemaphore and QSharedMemory created by running
   applications using Qt earlier than 5.6. Unfortunately, this means that Qt
   5.9 will not connect to 5.6-5.8.

 - QTouchEvent
   * Touch point ids are now unique even between different devices. As a
     consequence of that, you cannot anymore assume that
     QTouchEvent::TouchPoint::id has the same value as given by the native
     platform nor the same value as given by synthesized touch points.

****************************************************************************
*                               General Notes                              *
****************************************************************************

Deprecation Notice
------------------

 - QSysInfo::windowsVersion() and QSysInfo::macVersion() are deprecated and
   are replaced by the newly introduced class QOperatingSystemVersion.
 - [QTBUG-57288] Removed support for WinRT/Windows Phone 8.1.
 - Support for CMake < 3.1 is deprecated and will be removed in Qt 5.10.

Future Compatibility Notice
---------------------------

 - [QTBUG-59849] The identifiers that QSysInfo::productType() and
   QFileSelector will use to identify macOS systems will change in Qt 6.0
   to match the Apple naming guidelines which will be current then.

Potentially Source-Incompatible Changes
---------------------------------------

 - The internal Q_COMPILER_UNICODE_STRINGS macro is now defined if the
   compiler supports charNN_t, even if the standard library does not. To
   check for availability of std::uNNstring, use the new
   Q_STDLIB_UNICODE_STRINGS macro.

Third-Party Code
----------------

 - Sqlite was updated to version 3.16.1.
 - libpng was updated to version 1.6.28.
 - Bundled HarfBuzz-NG copy updated to 1.4.1
 - Gradle wrapper 3.4.1 was added as a third-party component (see
   src/3rdparty/gradle). The code is licensed under Apache License 2.0, and is
   used to create Android packages.
 - PCRE 8.39 (src/3rdparty/pcre) was removed as a third-party component.
 - PCRE 2 10.22 was added in src/3rdparty/pcre2 as a third-party
   component. The code is licensed under the BSD 3-clause "New" or "Revised"
   License, and is required by QRegularExpression (at least version 10.20).

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

QtCore
------

 - QProcessEnvironment is now available on iOS, tvOS, watchOS, and VxWorks.
 - [QTBUG-57715] QCoreApplication::applicationVersion now defaults to an
   appropriate platform-specific value. On Windows, it defaults to the
   PRODUCTVERSION parameter of the VERSIONINFO resource for classic desktop
   apps, and the version attribute of the application package manifest for
   Univeral Windows Platform apps. On Apple Platforms (macOS, iOS, tvOS,
   watchOS), it defaults to the CFBundleVersion property of the information
   property list (Info.plist) file. On Android, it defaults to the
   android:versionName attribute of the AndroidManifest.xml manifest
   element. On other platforms, the default remains an empty string.
 - Added QStaticByteArrayMatcher.
 - Added new qfloat16 class.
 - QStringLiteral is now guaranteed to be evaluated at compile-time. The
   last platform (QNX) to use the QString::fromUtf8() fallback has been
   ported to allocate the string data statically, too.

 - Event loop:
   * [QTBUG-33489][QTBUG-48717] QCoreApplication::flush() is now
     deprecated. Use QCoreApplication::processEvents() and
     QCoreApplication::sendPostedEvents() instead.

 - QByteArray:
   * Added toHex() overload to insert a separator character between the hex
     bytes.

 - QChar:
   * Disambiguated comparisons with nullptr constants such as '\0', which
     5.8.0 broke. As a consequence, QChar<->int comparisons are no longer
     deprecated, as this was a failed attempt at fixing the ambiguity.

 - QCryptographicHash:
   * [QTBUG-59770] QCryptographicHash now properly calculates SHA3 message
     digests. Before, when asked to calculate a SHA3 digest, it calculated
     a Keccak digest instead.

 - QDataStream:
   * Added operator<< and operator>> overloads that take std::nullptr_t, to
     facilitate generic code.
   * Added operator<< and operator>> for streaming QFlags into and out of
     QDataStreams.

 - QDateTime:
   * [QTBUG-52284][QTBUG-56397][QTBUG-56460][QTBUG-56345] Fixed a number of
     bugs related to handling of timezone offsets close to or during daylight
     savings changeovers, as well as timezones changing their standard
     offset.
   * [QTBUG-57298][QTBUG-57320] Fixed the handling of time zones in the
     toString() overload taking Qt::TextDate.

 - QDir:
   * Fixed a bug that caused QDir::mkpath() to create the wrong directory
     if the requested path contained a symbolic link and "../".
   * Added isEmpty(), that can help determining if a directory listing would
     be empty.

 - QFileInfo:
   * [QTBUG-48306] Made sure that all file lifecycle times are in local
     time. This was probably true before, but is now explicit.

 - QFileSelector:
   * [QTBUG-51230] Removed the requirement for an unused default base file
     in case you want to load only a variant.

 - QFlags:
   * Added operator<< and operator>> for streaming QFlags into and out of
     QDataStreams.

 - QHash / QMultiHash:
   * [QTBUG-60395] Fixed a bug that caused operator== to fail in the presence
     of duplicated keys.

 - QLocale:
   * Additional flags in QLocale::NumberOption allow generating strings
     from doubles in accordance to EcmaScript's Number.toPrecision(n).
   * Qt functions now always use the system time zone on Apple platforms,
     the same that low-level C APIs like localtime() does. Previously,
     converting dates and times to strings would use the "default" time
     zone (which is almost always the same as the "system" time zone but
     could be changed with the Apple API).

 - QLockFile:
   * [QTBUG-49640] Fixed a bug that caused QLockFile not to recognize a
     stale lock file if the machine's hostname contained non-US-ASCII
     characters, on Unix. A Windows fix is still pending.
   * Fixed a deadlock occurring if a corrupted lock file's modification
     time is in the future.

 - QMetaObject:
   * [QTBUG-60185] Fixed crash in QMetaObject::invokeMethod() and
     QMetaMethod::invoke() with QueuedConnection and types whose metatype gets
     automatically registered.

 - QObject:
   * QObject::dumpObjectInfo and QObject::dumpObjectTree are now fully
     functional even in a non-debug build of Qt.
   * QObject::dumpObjectInfo and QObject::dumpObjectTree now have const
     overloads.
   * Added a startTimer() overload taking std::chrono values.
   * [QTBUG-58054] Fixed an incompatibility with using noexcept functions as
     connect() targets in C++17 mode.

 - QSettings:
   * [QTBUG-34919] Added proper support for system-wide configuration file
     lookup based on XDG spec (XDG_CONFIG_DIRS) on Unix based systems.
   * [QTBUG-58531] Fixed data corruption when reading byte arrays on macOS.

 - QSharedPointer:
   * [QTBUG-49824] Fixed undefined behavior when creating an object with
     QSharedPointer::create() and its constructor throws an exception.

 - QStorageInfo:
   * Added QStorageInfo::subvolume(), which returns the name of the
     subvolume of a volume that was mounted, if one was detected. This is
     currently implemented only for btrfs on Linux.

 - QString:
   * toLocal8Bit() now preserves nullness of the input QString (outputs
     null QByteArray).
   * QString::null is now deprecated. When used to construct a QString, use
     QString() instead. When used to compare to a QString, replace with
     QString::isNull().

 - QStringRef:
   * toLocal8Bit() and toLatin1() now preserve nullness of the input
     QStringRef (output null QByteArrays).

 - QThreadPool:
   * The cancel() function suffers from several subtle issues and has been
     replaced with a new tryTake() function.

 - QUrl:
   * The temporary compatibility in QUrl::resolved() that treated the base
     URL as relative if its scheme matched the current URL's scheme has
     been removed.
   * [QTBUG-60364] Fixed a bug that caused certain domain names that look
     like Internationalized Domain Names to become corrupt in decoded forms
     of QUrl, notably toString() and toDisplayString().

 - QVarLengthArray:
   * Fixed a bug involving appending an item already in the container to
     the container again.
   * Added rvalue overloads of append() and push_back().

 - QVariant:
   * [QTBUG-56073] Fixed a bug that caused wrong results for comparisons of
     QVariants containing either NaN or infinite numbers.
   * Can now convert QUuid to and from QByteArray, not just QString.
   * [QTBUG-58296] isNull() now returns true if the QVariant contains nullptr.

QtGui
-----

 - OpenGL:
   * [QTBUG-55496] QOpenGLShaderProgram now offers a built-in program binary
     disk cache for systems with OpenGL ES 3.x or GL_ARB_get_program_binary.
     This can lead to significant increases in performance when it comes to
     application startup times for example.  Usage is opt-in for direct C++
     users of the class, however Qt's own main users of shaders, including Qt
     Quick and QPainter's OpenGL engine, are migrated to use the new,
     cache-enabled APIs. Opting out on application level is always possible
     via Qt::AA_DisableShaderDiskCache.

 - QIcon:
   * [QTBUG-49820] Implemented support for Scale directory key according to
     Icon Theme Spec. Icons created via QIcon::fromTheme() now have high
     DPI support by specifying the Scale in the appropriate entry of the
     relevant index.theme file.

 - QImage:
   * A new method reinterpretAsFormat() is has been added to change the
     format of a QImage without converting the data.

 - QMatrix4x4:
   * operator*=() now calculates the correct result even if the RHS and LHS
     are the same object.

 - QPA:
   * QPlatformScreen: Added an API to list available modes for a screen,
     that is resolution and refresh rate.
   * [QTBUG-58383] The function createForeignWindow() has been added to
     QPlatormIntegration and is now responsible for creating foreign
     windows. The function isForeignWindow() in QPlatformWindow has been
     added, and platforms should implement this to return true for windows
     created by createForeignWindow().

 - QPainter:
   * [QTBUG-28851] Fixed fills of negatively sized QRects.

 - QRgba64:
   * The default constructor on Clang and GCC builds now no longer
     initializes with 0s, but leaves the value uninitialized. This is
     consistent with MSVC behavior and pre-C++11 behavior of GCC and Clang.

 - QScreen:
   * Added manufacturer, model and serialNumber properties.

 - QTextLine:
   * Fixed a possible undefined behavior in the calculation of glyph right
     bearing when a QTextLine layout is performed.

 - QTouchEvent:
   * TouchPoint::rect(), sceneRect() and screenRect() are deprecated; a
     touchpoint is now modeled as an ellipse centered on a point, so please
     use pos(), scenePos(), screenPos(), and ellipseDiameters() instead.
   * QTouchEvent::TouchPoint::id values are now unique even between
     different devices.

 - QWindow:
   * [QTBUG-58383] The "_q_foreignWinId" dynamic property is no longer set
     nor read.

 - Text:
   * [QTBUG-56538] Added QTextDocument::toRawText() function.
   * [QTBUG-48005] Fixed clipping errors and too small bounding rects for
     some right-to-left text.
   * [QTBUG-57241] Fixed crash for very tall glyphs

QtNetwork
---------

 - The connect timeout from QAbstractSocket is now configurable through
   QNetworkConfiguration.
 - Added redirects policy to QNAM.
 - Added HTTP Strict Transport Security to QNAM.

 - Bearer management:
   * [QTBUG-56228][QTBUG-52988] Fixed a bug that could cause a crash on
     application exit, depending on the order of destruction of the
     QCoreApplication object and the QtDBus manager thread.

 - QHostAddress:
   * QHostAddress is now implicitly shared.
   * Added operator!=(SpecialAddress, QHostAddress).

 - QSslSocket:
   * Fixed connection to international domains (IDN) by normalizing to
     ASCII equivalent before comparing the host name in the certificate.
   * [QTBUG-56102] Allow QSslSocket (Secure Transport back-end) to use a temporary
     keychain on macOS instead of a default one; this can be enabled via a special
     environment variable QT_SSL_USE_TEMPORARY_KEYCHAIN (this feature is disabled
     by default).
   * [QTBUG-60233] QSslSocket (Secure Transport back-end) now respects CA
     certificates set in QSslConfiguration (before was always implicitly using
     the built-in anchor certificates in addition to a user provided configuration).
   * [QTBUG-59480] Added a missing cipher (Secure Transport).
   * [QTBUG-59930] Fixed spurious socket notifications in QCFSocketNotifer.
   * [QTBUG-58214] Fixed spurious socket notifications on Windows.

QtTest
------

 - QUuids are now printed on failure.
 - Added QTest::addRow(), which is like newRow(), but can take printf-style
   formatted strings.

QtWidgets
---------

 - [QTBUG-26116] QWidget now has a tabletTracking property, analogous to
   mouseTracking, which will enable TabletMove events while the stylus is
   hovering, even if no button is pressed. This allows applications to show
   feedback based on the other tablet event properties such as rotation and
   tilt.

 - Input:
   * [QTBUG-42074][QTBUG-57003] Characters in the Unicode Private Use Area, as
     well as zero-width joiners and zero-width non-joiners, are now accepted
     as input in QLineEdit and QTextEdit.

 - Qt::WA_WindowPropagation:
   * [QTBUG-59106] Locale is now propagated consistently, along with font and
     palette, within the widget hierarchy. Previously, setLocale() propagated
     the new locale from parents to children (recursively) but new children
     didn't inherit from their parents.

 - QColorDialog:
   * [QTBUG-58424] Fixed long standing bug that prevented custom colors in
     QColorDialog to be stored in the settings.

 - QDialog:
   * [QTBUG-6018][QTBUG-12156][QTBUG-14430] Fixed a bug where accessing the
     result of QDialog's result could yield an incorrect value in some
     situation like using it as a delegate for item views.

 - QErrorMessage:
   * Critical (QtCriticalMsg) and informational (QtInfoMsg) messages are now
     displayed properly. Previously, they appeared as if they were debug
     (QtDebugMsg) ones.

 - QFormLayout:
   * [QTBUG-58693][QTBUG-15990] The functions takeRow() and removeRow(),
     new in 5.8.0, now take and remove the correct row.

 - QMacStyle:
   * [QTBUG-57470] PE_IndicatorMenuCheckMark now looks for State_On instead of
     the State_Selected to set its highlighted state. Its color is picked from
     the style option palette.

 - QPixmapStyle:
   * Now handles progress bars with minimum != 0 correctly.

 - QSizePolicy:
   * Added transposed() method.

 - QSystemTrayIcon:
   * [QTBUG-49283] Support for custom icons in showMessage() was added.

 - QTextEdit:
   * [QTBUG-59196] Fixed initial char format of input method text as it is
     in pre-edit mode.

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

Android
-------

 - [QTBUG-44697] Removed old work-around which was causing OpenGL shader
   compilation to fail on updated Android emulators.
 - QTouchEvent::TouchPoints have correct ellipseDiameters() and rotation().

XCB/X11
-------
 - [QTBUG-60389] Every QTouchEvent includes up-to-date keyboard modifiers.
 - [QTBUG-59415] Every QTabletEvent includes up-to-date keyboard modifiers.

Linux
-----

 - Added an option to switch from mailbox to FIFO mode in eglfs' EGLStream
   backend. This is done by setting the environment variable
   QT_QPA_EGLFS_STREAM_FIFO_LENGTH to a >= 1 value, the desired length of the
   FIFO queue.
 - [QTBUG-57411] Added support for cross-compilation for the MIPS CI20.
 - Added support for cross-compilation targeting 64-bit Jetson TX1 systems.
 - Added support for cross-compilation targeting Renesas R-Car H2 (Lager)
   systems.
 - The Raspberry Pi 3 device specs have been renamed from linux-rpi3-* to
   linux-rasp-pi3-* in order to follow the pattern of the RPi 1 and 2 specs.
 - [QTBUG-57980] Added support for specifying the primary screen in the
   JSON config file in QT_QPA_EGLFS_KMS_CONFIG when running on DRM/KMS with
   eglfs.
 - The evdevtouch plugin now has the option to apply filtering and
   prediction. Enabled by passing "filtered" as an argument. Prediction can
   be specified by passing "prediction=X" as an argument, where X is in
   milliseconds.

 - linuxfb:
   * [QTBUG-56306] Added experimental support for DRM dumb buffers. Enable
     by setting the environment variable QT_QPA_FB_DRM to 1.

macOS
-----

 - Extra mouse buttons are now correctly be mapped to correct Qt::MouseButton
   values.

 - Accessibility:
   * [QTBUG-39008][QTBUG-54776][QTBUG-56043][QTBUG-57146] A common crash in
     accessibility on macOS was fixed.

Solaris
-------

 - [QTBUG-56293] Support for the Illumos distribution OpenIndiana (release
   "Hipster") has been added. This is a community-supported partial port.

Windows
-------

 - Support for Visual Studio 2017 has been added.
 - Fixed frameMargins for WM_NCCALCSIZE when handled inside with
   QAbstractNativeEventFilter.
 - [QTBUG-55510][QTBUG-48242] Windows are now automatically resized when they
   are moved on a screen to adapt to the new pixel ratio.
 - [QTBUG-58446] Fixed a bug that caused applications to crash with
   "Illegal instruction" faults when compiled with Visual Studio and run on
   some older processors.
 - [QTBUG-57023] Fixed a bug that caused QFile to create files with
   truncated names if the file name was invalid. Now, QFile::open correctly
   fails to create such files.

 - PDF:
   * [QTBUG-58954] Fixed a bug in PDF output when using high-dpi scaling
     which was causing the display of warnings when opening the file in
     Adobe Reader.

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

moc
---

 - [QTBUG-59351] Fixed parsing errors in presence of C++14 digit separators.
 - Added Support for C++17 nested namespaces
 - Move-only types are now supported as return types of signals and slots.

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

 - [QTBUG-30083] Generalized command line overrides of installation
   paths of external dependencies; see configure -help. Use configure
   -list-libraries to find about known libraries.
 - [QTBUG-42937][iOS] Added support for the configure -shared flag.
 - [QTBUG-56225] Re-introduced creation of config.summary.
 - [QTBUG-57908][QTBUG-59062] Fixed parsing of configure --xxx options.
 - [QTBUG-57656][macOS] Fixed installation of header-only modules like
   QtUiPlugin in framework builds of Qt.
 - [QTBUG-58321] Switching to a different qmakespec for user projects will
   now properly enable C++11 support if necessary.
 - [QTBUG-58411] Added configure -list-features option. This is useful
   for finding unnecessary features to disable with -no-feature-XXX.
 - [QTBUG-58511] Fixed QMAKE_CXXFLAGS, etc. assignments on the configure
   command line being ignored when building bootstrapped Qt tools while
   not cross-building (in cross-builds, they are intentionally ignored).
 - [QTBUG-60016] configure will now refuse to run if it finds variables
   in its environment which are known to cause trouble.
 - [QTBUG-60382] Fixed query of library paths from pkg-config.
 - Added possibility to merge ANGLE's libEGL and libGLESv2 into QtANGLE;
   configure option -combined-angle-lib.
 - [Windows] The -no-rtti configure option was removed, as Qt fails
   to build under that condition. To disable RTTI in user code, add
   CONFIG+=rtti_off to your project file.
 - [GCC] Debug builds of Qt are now optimized with -Og if available;
   use -no-optimize-debug to disable. This is also applicable to user
   projects; add CONFIG+=optimize_debug to your project file.
 - Added possibility to optimize release builds for size instea of speed;
   configure option -optimize-size.

qmake
-----

 - [QTBUG-51598] Libs.private is now written to .pc files only when building
   static libraries.
 - [QTBUG-55279] Static plugins are now imported also into dynamic libraries,
   not only executables. Various other improvements to static linking.
 - [QTBUG-56965][Darwin] Fixed overriding QMAKE_*_DEPLOYMENT_TARGET from
   within project files.
 - [QTBUG-57343] Fixed execution of extra compilers' depend_commands in build
   directories containing shell meta characters in their names,.
 - [QTBUG-57276] Fixed QMAKE_PRE_LINK (always) and QMAKE_POST_LINK (in one
   case) being ignored when building static libraries for Unix.
 - [QTBUG-57435][VS] Fixed capitalization of <PlatformToolset> tags in the
   generated vcxproj files.
 - [QTBUG-57694][VS] Fixed bogus ToolsVersion attributes in the generated
   vcxproj files.
 - [QTBUG-57914][VS] Fixed handling of RC_FILE when generating single-
   configuration vcxproj files.
 - [QTBUG-59630][VS] Fixed uninitialized value of GenerateDebugInformation,
   which was particularly bad if DebugFastLink was emitted for VS < 2015.
 - [QTBUG-58710][MSVC/nmake] Fixed overlong lines in response files generated
   for link.exe and lib.exe.
 - [QTBUG-57502][Darwin] Added support for launch images in asset catalogs.
 - [QTBUG-58126] Fixed the target compiler's default include and library paths
   interfering with the build of host tools when cross-building.
 - [QTBUG-58764] Fixed building of moc'able files with a Qt installation
   in a path containing spaces.
 - [QTBUG-58857] Added the ability to use CONFIG+=no_moc_predefs to suppress
   the collection of the compiler's predefined macros for moc's use.
 - [QTBUG-59004][Windows] '(n)make install' will now copy the timestamps of
   the installed files, like it was already done on Unix.
 - [QTBUG-59319] Fixed $$shadowed() function for the case where the source
   tree lives in a symlinked or substituted path.
 - [QTBUG-59779][Android][MinGW] Fixed CONFIG+=separate_debug_info.
 - [QTBUG-38782][iOS] Added support for setting the Xcode development team
   and provisioning profile.
 - [QTBUG-58754][iOS] Fixed handling of bitcode.
 - [Darwin] Binaries now automatically get @executable_path/Frameworks
   added to RPATH, and libraries additionally @loader_path/Frameworks.
   Suppress with CONFIG+=no_default_rpath.
 - [Darwin][Xcode] QMAKE_BUNDLE_DATA now supports embedding Frameworks
   and PlugIns.
 - [macOS] Support for universal binaries has been re-introduced.
 - Added the command line options -early and -late, plus -before (which is
   the default) for symmetry with -after.
 - The $$prompt() function will now exit qmake upon EOF on stdin.
 - The touch() function now uses nanosecond precision if available.
 - [MSVC] Qt now has a common mkspec for all Visual Studio versions, called
   "win32-msvc". The old names which contained the version number are now
   gone (but qmake scopes based on the old names continue to work).
   In qmake project files, the version of the compiler can be obtained from
   the MSC_VER and MSVC_VER variables (for example, for Visual Studio 2015,
   those contain the values 1900 and 14.0, respectively). Those variables
   are also available with the Intel compiler (win32-icc) and with Clang
   (win32-clang-msvc).
 - [Windows] The win32-clang-msvc qmakespec will now adjust the emulated
   MSVC version to match that of the cl.exe found in PATH.
 - [Windows] Fixed make 'install' targets to be idempotent.
 - [Windows] '(n)make install' will not fail on file names containing the
   plus sign any more.
 - Numerous obsolete qmakespecs have been pruned.