From b398515b09d23b5b94d16676b709de6c0b382e56 Mon Sep 17 00:00:00 2001 From: Mitch Curtis Date: Mon, 30 Jun 2014 09:56:26 +0200 Subject: Tidy up and expand QSharedPointer documentation. Also adds the 5.4.0 changes file. Change-Id: I10967ca179b91229e7d1ee0fc666bbd8dbe54425 Reviewed-by: Jerome Pasion Reviewed-by: Thiago Macieira --- src/corelib/tools/qsharedpointer.cpp | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) (limited to 'src/corelib/tools/qsharedpointer.cpp') diff --git a/src/corelib/tools/qsharedpointer.cpp b/src/corelib/tools/qsharedpointer.cpp index 180f45eb56..e0cd54022e 100644 --- a/src/corelib/tools/qsharedpointer.cpp +++ b/src/corelib/tools/qsharedpointer.cpp @@ -374,12 +374,12 @@ /*! \class QEnableSharedFromThis \inmodule QtCore - \brief A base class that allows to obtain a QSharedPointer for an object already managed by a shared pointer + \brief A base class that allows obtaining a QSharedPointer for an object already managed by a shared pointer \since 5.4 You can inherit this class when you need to create a QSharedPointer - from any instance of a class -- for instance, from within the - object itself. The key point is that the "obvious" technique of + from any instance of a class; for instance, from within the + object itself. The key point is that the technique of just returning QSharedPointer(this) can not be used, because this winds up creating multiple distinct QSharedPointer objects with separate reference counts. For this reason you must never @@ -406,6 +406,27 @@ Q_ASSERT(p == y); // p and q must share ownership } \endcode + + It is also possible to get a shared pointer from an object outside of + the class itself. This is especially useful in code that provides an + interface to scripts, where it is currently not possible to use shared + pointers. For example: + + \code + class ScriptInterface : public QObject + { + Q_OBJECT + + // ... + + public slots: + void slotCalledByScript(Y *managedBySharedPointer) + { + QSharedPointer yPtr = managedBySharedPointer->sharedFromThis(); + // Some other code unrelated to scripts that expects a QSharedPointer ... + } + }; + \endcode */ /*! -- cgit v1.2.3