boost::make_shared and C++Builder VCL objects

Question

I've tried switching some C++Builder 2010 code using new to use boost::make_shared<>, as below.

Old:

boost::shared_ptr<TStringList> l(new TStringList());

New:

boost::shared_ptr<TStringList> l(boost::make_shared<TStringList>());

l->Add("foo"); //dies here

The old code works, but the new code dies when I try and use the pointer (AV, or just hangs). I've used make_shared and shared_ptr successfully before, but never with TObject descendants. Is this a known problem - perhaps something to do withe the way make_shared uses placement new() ??

Answer 1

I imagine the placement new is indeed problematic because TObject has expectations about memory allocations which new satisfies (because C++Builder's RTL internally routes C/C++ memory routines to Delphi RTL routines in VCL projects), but which placement new does not.