What is a segmentation fault?
Core Dump/Segmentation fault is a specific kind of error caused by accessing memory that “does not belong to you.”
Huh? What? Where and how am I doing this?? During the construction of your object (not exactly in the constructor).
— Then, nonstatic data members shall be initialized in the order they were ...
Your crashes is mostly because of improper handling of the object's ownership.
When you add something to a collection, you should clearly understand who's owning the object. Is that handler owns the added objects now, and may delete those when time has come? Or is that handler only references the objects, and there's some other subsystem that will destroy ...