Documentation: Add \nullptr macro and use where applicable

Qt for Python users reading the documentation assume that int(0) can
be passed for pointer parameters. Use the newly introduced \nullptr to
disambiguate this.

In a follow-up step, the \nullptr macro can be defined as None
when generating the Qt for Python documentation.

Task-number: PYSIDE-903
Change-Id: I3a45f87175a0668ab5f3f95f0aff409f7e3ef027
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>
Reviewed-by: Christian Tismer <tismer@stackless.com>
Reviewed-by: Venugopal Shivashankar <Venugopal.Shivashankar@qt.io>
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

7 files changed, 8 insertions, 8 deletions

diff --git a/src/gui/kernel/qevent.cpp b/src/gui/kernel/qevent.cpp
index 53d1ac1fc0..7123c4d8ba 100644
--- a/src/gui/kernel/qevent.cpp
+++ b/src/gui/kernel/qevent.cpp
@@ -3072,7 +3072,7 @@ QDropEvent::~QDropEvent()
 /*!
     If the source of the drag operation is a widget in this
     application, this function returns that source; otherwise it
-    returns 0. The source of the operation is the first parameter to
+    returns \nullptr. The source of the operation is the first parameter to
     the QDrag object used instantiate the drag.
 
     This is useful if your widget needs special behavior when dragging
@@ -3514,7 +3514,7 @@ QActionEvent::~QActionEvent()
     \fn QAction *QActionEvent::before() const
 
     If type() is \l ActionAdded, returns the action that should
-    appear before action(). If this function returns 0, the action
+    appear before action(). If this function returns \nullptr, the action
     should be appended to already existing actions on the same
     widget.
 
diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index a63e172461..fd01f8bb7b 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -3747,7 +3747,7 @@ Qt::LayoutDirection QGuiApplication::layoutDirection()
 
     Returns the active application override cursor.
 
-    This function returns 0 if no application cursor has been defined (i.e. the
+    This function returns \nullptr if no application cursor has been defined (i.e. the
     internal cursor stack is empty).
 
     \sa setOverrideCursor(), restoreOverrideCursor()
diff --git a/src/gui/kernel/qopenglcontext.cpp b/src/gui/kernel/qopenglcontext.cpp
index c5d5490ea0..be04513de6 100644
--- a/src/gui/kernel/qopenglcontext.cpp
+++ b/src/gui/kernel/qopenglcontext.cpp
@@ -1118,7 +1118,7 @@ void QOpenGLContext::swapBuffers(QSurface *surface)
 /*!
     Resolves the function pointer to an OpenGL extension function, identified by \a procName
 
-    Returns 0 if no such function can be found.
+    Returns \nullptr if no such function can be found.
 */
 QFunctionPointer QOpenGLContext::getProcAddress(const QByteArray &procName) const
 {
diff --git a/src/gui/kernel/qplatformcursor.cpp b/src/gui/kernel/qplatformcursor.cpp
index bab26f6028..76e38ab12d 100644
--- a/src/gui/kernel/qplatformcursor.cpp
+++ b/src/gui/kernel/qplatformcursor.cpp
@@ -84,7 +84,7 @@ QT_BEGIN_NAMESPACE
 
     \a windowCursor is a pointer to the QCursor that should be displayed.
 
-    To unset the cursor of \a window, 0 is passed. This means \a window does not have
+    To unset the cursor of \a window, \nullptr is passed. This means \a window does not have
     a cursor set and the cursor of a the first parent window which has a cursor explicitly
     set or the system default cursor should take effect.
 
diff --git a/src/gui/kernel/qplatformintegration.cpp b/src/gui/kernel/qplatformintegration.cpp
index 6e285a8fa5..7d1fcd4eeb 100644
--- a/src/gui/kernel/qplatformintegration.cpp
+++ b/src/gui/kernel/qplatformintegration.cpp
@@ -350,7 +350,7 @@ void QPlatformIntegration::destroy()
 /*!
   Returns the platforms input context.
 
-  The default implementation returns 0, implying no input method support.
+  The default implementation returns \nullptr, implying no input method support.
 */
 QPlatformInputContext *QPlatformIntegration::inputContext() const
 {
diff --git a/src/gui/kernel/qplatformscreen.cpp b/src/gui/kernel/qplatformscreen.cpp
index 9614be7f3e..b7b312e89e 100644
--- a/src/gui/kernel/qplatformscreen.cpp
+++ b/src/gui/kernel/qplatformscreen.cpp
@@ -370,7 +370,7 @@ QString QPlatformScreen::serialNumber() const
 /*!
     Reimplement this function in subclass to return the cursor of the screen.
 
-    The default implementation returns 0.
+    The default implementation returns \nullptr.
 */
 QPlatformCursor *QPlatformScreen::cursor() const
 {
diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index bc2d6e6a17..61ef029cbd 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -2644,7 +2644,7 @@ QOpenGLContext *QWindowPrivate::shareContext() const
     native window, or to embed a native window inside a QWindow.
 
     If foreign windows are not supported or embedding the native window
-    failed in the platform plugin, this function returns 0.
+    failed in the platform plugin, this function returns \nullptr.
 
     \note The resulting QWindow should not be used to manipulate the underlying
     native window (besides re-parenting), or to observe state changes of the