# How does io redirection work with tasks?
**URL:** https://discourse.julialang.org/t/how-does-io-redirection-work-with-tasks/112405
**Category:** General Usage
**Tags:** task, async
**Created:** [April 2, 2024, 8:46am UTC](https://discourse.julialang.org/t/how-does-io-redirection-work-with-tasks/112405 "2024-04-02T08:46:30Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@jules](https://discourse.julialang.org/u/jules)
#### Post date: [April 2, 2024, 8:46am UTC](https://discourse.julialang.org/t/how-does-io-redirection-work-with-tasks/112405/1 "2024-04-02T08:46:30Z")
I don’t understand this simple MWE:
```julia
julia> redirect_stdio(;stdout = devnull) do
@async println("hello")
@async redirect_io(; stdout = devnull) do
println("hey")
end
println("hi")
end
hello
```
The docstring of `redirect_stdio` doesn’t mention anything about it not affecting child tasks. How does this actually work?
---
### Author:  [@Benny](https://discourse.julialang.org/u/Benny)
#### Post date: [April 2, 2024, 9:46pm UTC](https://discourse.julialang.org/t/how-does-io-redirection-work-with-tasks/112405/2 "2024-04-02T21:46:33Z")
The `do` block seems to complete without interruption, the streams restored, and then the tasks run. If you do something to interrupt the `do` block and go to the scheduler:
```julia
julia> redirect_stdio(;stdout = devnull) do
@async println("hello")
sleep(0)
@async redirect_io(; stdout = devnull) do
println("hey")
end
println("hi")
end
```
---
### Author:  [@jar1](https://discourse.julialang.org/u/jar1)
#### Post date: [April 2, 2024, 11:56pm UTC](https://discourse.julialang.org/t/how-does-io-redirection-work-with-tasks/112405/3 "2024-04-02T23:56:28Z")
My preference is to never let a block return if tasks created in that block are still running.
```julia
julia> Base.redirect_stdio(;stdout = devnull) do
@sync begin
@async println("hello")
@async Base.redirect_stdio(; stdout = devnull) do
println("hey")
end
println("hi")
end
end
julia>
```