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Version: 2.0.x


An Exit[E, A] value describes how fibers end life. It has two possible values:

  • Exit.Success contain a success value of type A.
  • Exit.Failure contains a failure Cause of type E.

This is how the Exit data type is defined:

sealed abstract class Exit[+E, +A] extends Product with Serializable { self =>
// Exit operators
object Exit {
final case class Success[+A](value: A) extends Exit[Nothing, A]
final case class Failure[+E](cause: Cause[E]) extends Exit[E, Nothing]

We can call ZIO#exit on our effect to determine the Success or Failure of our fiber:

import zio._
import zio.Console._


val result: ZIO[Any, IOException, Unit] =
for {
successExit <- ZIO.succeed(1).exit
_ <- successExit match {
case Exit.Success(value) =>
printLine(s"exited with success value: ${value}")
case Exit.Failure(cause) =>
printLine(s"exited with failure state: $cause")
} yield ()