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Diffstat (limited to 'doc/src/snippets/code/src_corelib_tools_qscopedpointer.cpp')
-rw-r--r-- | doc/src/snippets/code/src_corelib_tools_qscopedpointer.cpp | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/doc/src/snippets/code/src_corelib_tools_qscopedpointer.cpp b/doc/src/snippets/code/src_corelib_tools_qscopedpointer.cpp new file mode 100644 index 0000000000..be28d56eb2 --- /dev/null +++ b/doc/src/snippets/code/src_corelib_tools_qscopedpointer.cpp @@ -0,0 +1,138 @@ +/**************************************************************************** +** +** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor +** the names of its contributors may be used to endorse or promote +** products derived from this software without specific prior written +** permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** $QT_END_LICENSE$ +** +****************************************************************************/ + +//! [0] +void myFunction(bool useSubClass) +{ + MyClass *p = useSubClass ? new MyClass() : new MySubClass; + QIODevice *device = handsOverOwnership(); + + if (m_value > 3) { + delete p; + delete device; + return; + } + + try { + process(device); + } + catch (...) { + delete p; + delete device; + throw; + } + + delete p; + delete device; +} +//! [0] + +//! [1] +void myFunction(bool useSubClass) +{ + // assuming that MyClass has a virtual destructor + QScopedPointer<MyClass> p(useSubClass ? new MyClass() : new MySubClass); + QScopedPointer<QIODevice> device(handsOverOwnership()); + + if (m_value > 3) + return; + + process(device); +} +//! [1] + +//! [2] + const QWidget *const p = new QWidget(); + // is equivalent to: + const QScopedPointer<const QWidget> p(new QWidget()); + + QWidget *const p = new QWidget(); + // is equivalent to: + const QScopedPointer<QWidget> p(new QWidget()); + + const QWidget *p = new QWidget(); + // is equivalent to: + QScopedPointer<const QWidget> p(new QWidget()); +//! [2] + +//! [3] +if (scopedPointer) { + ... +} +//! [3] + +//! [4] +class MyPrivateClass; // forward declare MyPrivateClass + +class MyClass +{ +private: + QScopedPointer<MyPrivateClass> privatePtr; // QScopedPointer to forward declared class + +public: + MyClass(); // OK + inline ~MyClass() {} // VIOLATION - Destructor must not be inline + +private: + Q_DISABLE_COPY(MyClass) // OK - copy constructor and assignment operators + // are now disabled, so the compiler won't implicitely + // generate them. +}; +//! [4] + +//! [5] +// this QScopedPointer deletes its data using the delete[] operator: +QScopedPointer<int, QScopedPointerArrayDeleter<int> > arrayPointer(new int[42]); + +// this QScopedPointer frees its data using free(): +QScopedPointer<int, QScopedPointerPodDeleter> podPointer(reinterpret_cast<int *>(malloc(42))); + +// this struct calls "myCustomDeallocator" to delete the pointer +struct ScopedPointerCustomDeleter +{ + static inline void cleanup(MyCustomClass *pointer) + { + myCustomDeallocator(pointer); + } +}; + +// QScopedPointer using a custom deleter: +QScopedPointer<MyCustomClass, ScopedPointerCustomDeleter> customPointer(new MyCustomClass); +//! [5] |