The smart pointers Rc and Arc provide reference counting. What is the API for incrementing a reference count?

What happens when an error occurs that is being handled by the question mark (?) operator?

Which comment syntax is not legal?

In matching patterns, values are ignored with _.

Defining a _ requires a lifetime parameter.

Which statement about lifetimes is false?

_ cannot be destructured.

Which choice is not a scalar data type?

Which type cast preserves the mathematical value in all cases?

Which of the following provides the most random seed source for a pseudo random number generator?

The purpose of the poll() and select() system calls is to perform which of the following functions?