examples/SFExamples/Example_RArray/ThingsNotToDo.cpp

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Description:  
*/ 
#include "ThingsNotToDo.h"
#include "SharedCode.h"

// ---------------------------------------------------------
// void AllocRArrayObjectsL()
// This shows how its possible to leak memory if RArray
// are put onto the heap.
// ---------------------------------------------------------
//
LOCAL_C void AllocRArrayObjectsL()
        {
        // put the array on the stack
        // this goes in as a TAny* pointer with a granulatiry of 8
        RExampleArray* array = new (ELeave) RExampleArray;
        CleanupStack::PushL(array);
        
        // now add an item so the array allocates resources
        // internally
        TExampleStruct s = {1,2};
        User::LeaveIfError(array->Append(s));
        
        // Now if we leave the memory allocated for RExampleArray
        // gets deleted but 
        // a) its destructor will not be called
        // b) the resources allocated when we addded an item
        //    will not be cleaned up
        User::Leave(KErrGeneral);
        
        // This never gets called - its intentional!
        CleanupStack::PopAndDestroy(array);
        }

// ---------------------------------------------------------
// void UnalignedDataL()
// Shows how to cause an alignment issue using RArray
// This is typical use case that has come up and is a result
// of the array elements not being the correct minimum size
// ---------------------------------------------------------
//
LOCAL_C void UnalignedDataL()
        {
        TUint8 data[] = {1,2,3,4,5};
        
        // NOTE: No resource management as this code
        // will panic anyway.
        RArray<TUint8> array;
        
        // we pass in a reference not aligned
        // to a 32 bit address so it panics
        // with an alignment fault
        array.Append(data[3]);
        }

// ---------------------------------------------------------
// void ThingsNotToDoL()
// Shows the things not do with RArrays
// ---------------------------------------------------------
//
void ThingsNotToDoL()
        {
        // Create an RArray on the heap 
        AllocRArrayObjectsL();
        
        // misaligned data will cause a panic
        UnalignedDataL();
        }

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