[GiNaC-list] Getting a pointer to an element in a list?

Hi all A hopefully pretty simple question about lists in GiNaC. I have a little fragment of code like this: class SymbolicSystem{ private: GiNaC::lst F; public: const ex * getExpressionPtr(const unsigned &i) const{ *return* &(F[i]); } } Is there something about the implementation of the operator[] in GiNaC::list that stops me from being able to do this? GCC gives me a warning, like this: warning: taking address of temporary This might be an elementary C++ mistake, but just in case, I thought I'd ask. Cheers JP