Will this C++ code cause a memory leak (casting array new)

Question

I have been working on some legacy C++ code that uses variable length structures (TAPI), where the structure size will depend on variable length strings. The structures are allo

Answer 1

As highlighted in other posts:

1) Calls to new/delete allocate memory and may call constructors/destructors (C++ '03 5.3.4/5.3.5)

2) Mixing array/non-array versions of new and delete is undefined behaviour. (C++ '03 5.3.5/4)

Looking at the source it appears that someone did a search and replace for malloc and free and the above is the result. C++ does have a direct replacement for these functions, and that is to call the allocation functions for new and delete directly:

STRUCT* pStruct = (STRUCT*)::operator new (sizeof(STRUCT) + nPaddingSize);
// ...
pStruct->~STRUCT ();  // Call STRUCT destructor
::operator delete (pStruct);

If the constructor for STRUCT should be called, then you could consider allocating the memory and then use placement new:

BYTE * pByteData = new BYTE[sizeof(STRUCT) + nPaddingSize];
STRUCT * pStruct = new (pByteData) STRUCT ();
// ...
pStruct->~STRUCT ();
delete[] pByteData;