How deeply does 100 C++ Mistakes and How to Avoid Them cover unique object?

Explains implicit copy construction, private declarations, member-function loopholes, and deleted operations.

Unique object

As explained in 100 C++ Mistakes and How to Avoid Them

A unique object is an object whose identity or existence must not be duplicated within the modeled domain.

A unique object represents a domain concept that must not be duplicated. Copying such an object violates its class invariant, even when the program compiles and runs normally. section 9.2

Avoid the duplication mistake by checking every copy operation:

Hiding only the copy assignment operator is insufficient: the compiler can still provide a default copy constructor. section 9.2

A duplicated artwork

Constructing ArtPiece dup(ml) prints “Mona Lisa” twice: the compiler-created copy constructor silently produces a second object, with no visible forgery warning.

How 100 C++ Mistakes and How to Avoid Them covers it

Cover of 100 C++ Mistakes and How to Avoid Them

liveBook manning.com

Read 100 C++ Mistakes and How to Avoid Them on liveBook Get the book at manning.com

Related concepts

copy constructorproduced by · A copy constructor is a constructor that initializes a new object from an existing object of the same class or type.
distinct valuecontrasts with · A distinct value is a value different from others in a collection, counted once regardless of how many times it occurs.

This explainer was generated by Manning's knowledge graph from the text of 100 C++ Mistakes and How to Avoid Them. The section links point to the parts of the book it draws on.