Setting a unique_ptr to nullptr is supported by C++11 standard.

1. Declaring a unique_ptr without definition fills the pointer with nullptr

2. unique_ptr has dedicated overloaded assignment operator to update its value

   • The object previously pointed to by the pointer is destroyed
   • Effectively equivalent to unique_ptr::reset() with no argument

References:

• https://stackoverflow.com/questions/15070862/can-a-unique-ptr-take-a-nullptr-value
• https://en.cppreference.com/w/cpp/memory/unique_ptr/reset