kotlin-stdlib / kotlin / OptIn / <init>

<init>

Common
JVM
JS
Native
1.0
OptIn(vararg markerClass: KClass<out Annotation>)

Allows to use the API denoted by the given markers in the annotated file, declaration, or expression. If a declaration is annotated with OptIn, its usages are not required to opt in to that API.

markerClass specifies marker annotations that require explicit opt-in. The marker annotation is not required to be itself marked with RequiresOptIn to enable gradual migration of API from requiring opt-in to the regular one, yet declaring such OptIn yields a compilation warning.

See also Kotlin language documentation for more information.