gistfile1.c

#define erase_memory(data,data_length) \
	({ typeof (data) data_ = (data);          \
        typeof (data_length) data_length_ = (data_length);          \
        __builtin_choose_expr( \
        		__builtin_constant_p(data_),  \
        		__builtin_choose_expr( \
        				__builtin_choose_expr(__builtin_constant_p(data_), data_, 0), \
        				_erase_memory(data_,data_length_), \
        				0\
        		), \
        		data_?_erase_memory(data_,data_length_):0 \
        ); })