# How do I get an error in a try catch to end all running tasks

**URL:** <https://discourse.julialang.org/t/how-do-i-get-an-error-in-a-try-catch-to-end-all-running-tasks/97830>\
**Category:** General Usage\
**Created:** [April 23, 2023, 10:31pm UTC](https://discourse.julialang.org/t/how-do-i-get-an-error-in-a-try-catch-to-end-all-running-tasks/97830 "2023-04-23T22:31:03Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Zentrik](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/zentrik/32/35409_2.png) [@Zentrik](https://discourse.julialang.org/u/Zentrik)\
**Post date:** [April 23, 2023, 10:31pm UTC](https://discourse.julialang.org/t/how-do-i-get-an-error-in-a-try-catch-to-end-all-running-tasks/97830/1 "2023-04-23T22:31:04Z")

</div>

In the code below when the first task throws an error I want it to kill the second task immediately and then go to the catch block. I think the code currently ends the first task and then just runs the second task, and if it finished it would then go to the catch block.

```julia
try 
    @sync begin
        @async throw(ArgumentError)
        @async while true
            sleep(2)
            println("oops")
        end
    end
catch err
    println("Caught")
end

```

This code also exhibits the similar behaviour, where it does immediately go to the catch block but the while loop doesn’t end

```julia
try 
    @sync begin
        @async while true
            sleep(2)
            println("oops")
        end
        throw(ArgumentError)
    end
catch err
    println("Caught")
end

```

What do I need to do to get the desired behaviour of all tasks stopping when an error is thrown?

---

<div class="post-metadata">

**Author:** ![Zentrik](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/zentrik/32/35409_2.png) [@Zentrik](https://discourse.julialang.org/u/Zentrik)\
**Post date:** [April 29, 2023, 8:15am UTC](https://discourse.julialang.org/t/how-do-i-get-an-error-in-a-try-catch-to-end-all-running-tasks/97830/2 "2023-04-29T08:15:01Z")

</div>

These two solutions work for me. It seems it is easiest to end a task if you are waiting on some `x`  
in the task for which you can call `close(x)` when you have an error, which closes the task waiting on `x`. That’s why we use `Timer` here.

```julia
try 
    @sync let timer
        @async begin
            timer = Timer(2) do _
                println("oops")
            end
        end

        try
            @sync begin
                @async throw(ArgumentError)
            end
        catch err
            println("Caught 1")
            close(timer)
            rethrow()
        end
    end
catch err
    println("Caught")
end

```

```julia
try 
    @sync let timer
        @async begin
            timer = Timer(2) do _
                println("oops")
            end
        end

        try
            throw(ArgumentError)
        catch err
            println("Caught 1")
            close(timer)
            rethrow()
        end
    end
catch err
    println("Caught")
end

```