CODEWITHSUNDEEP
c++smart-pointers
Nathan Ridley
Nathan Ridley

Reputation: 34396

How do I create and initialize unique_ptr from a copy of an existing object in a single statement?

Imagine I have const Matrix IDENTITY_MATRIX defined somewhere, ready to be copied whenever I need it as a baseline. Matrix is just a struct.

If I want to create a smart pointer to a new Matrix instance, initialized with a copy of IDENTITY_MATRIX, I could do this:

std::unique_ptr<Matrix> foo(new Matrix);
*foo = IDENTITY_MATRIX;

Is there a way to perform the initialization using a single statement? I don't want to have to write a helper function to do this. If that is required, I'll settle for initialization with two statements.

Upvotes: 1

Views: 5329

Answers (1)

Columbo
Columbo

Reputation: 60969

Use the new expression to provide an initializer

std::unique_ptr<Matrix> foo(new Matrix(IDENTITY_MATRIX));

Or use make_unique

auto foo = std::make_unique<Matrix>(IDENTITY_MATRIX);

Upvotes: 3

Related Questions