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  1. Qt
  2. QTBUG-14636 QSharedPointer is not exception-safe
  3. QTBUG-14637

QSharedPointer's constructor dereferences uninitialised data in case of exception thrown

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    • 3bb0cf4

    Description

      If operator new throws, the following code will dereference uninitialised memory:

          QSharedPointer<A> ptr(new A);

      qsharedpointer_impl.h: In function 'int main(int, char**)':
qsharedpointer_impl.h:337: warning: 'a.QSharedPointer<A>::<anonymous>.QtSharedPointer::ExternalRefCount<A>::d' may be used uninitialized in this function                                                                        
main.cpp:16: note: 'a.QSharedPointer<A>::<anonymous>.QtSharedPointer::ExternalRefCount<A>::d' was declared here
qsharedpointer_impl.h:340: warning: 'a.QSharedPointer<A>::<anonymous>.QtSharedPointer::ExternalRefCount<A>::<anonymous>.QtSharedPointer::Basic<A>::value' may be used uninitialized in this function

      The reason is that QSharedPointer::QSharedPointer(T*) leaves its base uninitialised, then calls a function that may throw (internalConstruct). If that throws, then the parent class's destructor is run, which proceeds to dereference the uninitialised members.

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            tmacieir Thiago Macieira (closed Nokia identity) (Inactive)
            tmacieir Thiago Macieira (closed Nokia identity) (Inactive)
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