Does initializing a variable in the init function of a package ensures a single instance in a golang app?

Question

I am writing a Bloom Filter package. Within my package, I want to create an instance of X (non-exported) which I want to exist only as a single instance; no matter how many times my package is imported into an app.

A simple snippet of what I am doing is:

package superduperbloomfilter

var x X

func init() {
    x = X.New(....)
}

Is this correct ?

Answer 1

which I want to exist only as a single instance; no matter how many times my package is imported into an app

The spec says an imported package is initialized only once:

If a package has imports, the imported packages are initialized before initializing the package itself. If multiple packages import a package P, P will be initialized only once.