Why is using vector of pointers considered bad?

Question

Recently I\'ve met with opinion that I shouldn\'t use vector of pointers. I wanted to know - why I cant?

For example if I have a class foo it is possib

Answer 1

One of the problems is exception-safety.

For example, suppose that somewhere an exception is thrown: in this case, the destructor of std::vector is called. But this destructor call does not delete the raw owning pointers stored in the vector. So, the resources managed by those pointers are leaked (these can be both memory resources, so you have a memory leak, but they could also be non-memory resources, e.g. sockets, OpenGL textures, etc.).

Instead, if you have a vector of smart pointers (e.g. std::vector>), then if the vector's destructor is called, each pointed item (safely owned by a smart pointer) in the vector is properly deleted, calling its destructor. So, the resources associated to each item ("smartly" pointed to in the vector) are properly released.

Note that vectors of observing raw pointers are fine (assuming that the lifetime of the observed items exceeeds that of the vector). The problem is with raw owning pointers.