# How can \`sleep(0.001)\` error?
**URL:** https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394
**Category:** General Usage
**Tags:** question
**Created:** [April 23, 2024, 1:38pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394 "2024-04-23T13:38:38Z")
**Posts on this page:** 15
**Page:** 1
### Author:  [@SunnyUser](https://discourse.julialang.org/u/SunnyUser)
#### Post date: [April 23, 2024, 1:38pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/1 "2024-04-23T13:38:38Z")
Hi all 🙂
How can `sleep(0.001)` error?
```julia
┌ Error:
│ EOFError: read end of file
│ Stacktrace:
│ [1] wait
│ @ .\asyncevent.jl:159 [inlined]
│ [2] sleep
│ @ .\asyncevent.jl:265 [inlined]
```
This happend on Windows. Julia v10.0.0
Thanks all!
---
### Author:  [@stevengj](https://discourse.julialang.org/u/stevengj)
#### Post date: [April 23, 2024, 1:40pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/2 "2024-04-23T13:40:07Z")
Please post a minimal working snippet of code that triggers this error for you. [Please read: make it easier to help you](https://discourse.julialang.org/t/please-read-make-it-easier-to-help-you/14757)
---
### Author:  [@SunnyUser](https://discourse.julialang.org/u/SunnyUser)
#### Post date: [April 23, 2024, 2:00pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/3 "2024-04-23T14:00:16Z")
Hard to give a minimal working snippet. Just can tell that it happens almost never (my feeling 1 in 10^15).
The surrounding code is a `while-true` with a inner `try-catch` and a pulling `ccall`. All this runs in a separate task.
---
### Author:  [@giordano](https://discourse.julialang.org/u/giordano)
#### Post date: [April 23, 2024, 2:14pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/4 "2024-04-23T14:14:53Z")
> [@SunnyUser](#):
>
> Hard to give a minimal working snippet.
It shouldn’t be hard to share the code you’re actually trying to run. You only showed a partial error message.
---
### Author:  [@SunnyUser](https://discourse.julialang.org/u/SunnyUser)
#### Post date: [April 23, 2024, 2:26pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/5 "2024-04-23T14:26:30Z")
I can do that… But I have to remove company code. But the following function gets spawned in at task.
```julia
function get_next_item()
while _IS_RUNNING[]
try
return_buffer = managed_allocating_ccall(
ccall_get_next_item
)
if isnothing(return_buffer)
sleep(0.001)
continue
end
distribute_to_channels(
deserialize_item(return_buffer)...
)
catch e
@error(
sprint(showerror, e, catch_backtrace())
)
end
end
end
```
and
```julia
function managed_allocating_ccall(allocating_ccall::Function)::Union{IOBuffer, Nothing}
(return_value_ptr, return_value_length) = allocating_ccall()
if return_value_ptr == Ptr{UInt8}()
return nothing
end
return_value_length_buffer = IOBuffer(return_value_length)
return_value_length = read(return_value_length_buffer, Int32)
return_value = unsafe_wrap(Vector{UInt8}, return_value_ptr, return_value_length)
return_value = deepcopy(return_value)
ccall_free(return_value_ptr)
return IOBuffer(return_value)
end
```
and
```julia
function ccall_get_next_item()
return_value_length = zeros(UInt8, 4)
return_value_ptr = @my_semaphore_lock begin
GC.@preserve return_value_length begin
@ccall $C_ABI_POINTER_GET_NEXT_ITEM(
pointer(return_value_length)::Ptr{UInt8},
)::Ptr{UInt8}
end
end with Semaphore _CCALL_SEMAPHORE
(return_value_ptr, return_value_length)
end
```
---
### Author:  [@SunnyUser](https://discourse.julialang.org/u/SunnyUser)
#### Post date: [June 14, 2024, 11:31am UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/6 "2024-06-14T11:31:21Z")
I got this error again in production. I have no idea to debug or fix it. Can me help anybody?
---
### Author:  [@barucden](https://discourse.julialang.org/u/barucden)
#### Post date: [June 14, 2024, 11:45am UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/7 "2024-06-14T11:45:59Z")
Wrap `sleep` in a try-catch block and ignore `EOFError`:
```julia
try
sleep(0.001)
catch ex
ex isa EOFError || rethrow()
end
```
---
### Author:  [@SunnyUser](https://discourse.julialang.org/u/SunnyUser)
#### Post date: [June 14, 2024, 11:53am UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/8 "2024-06-14T11:53:55Z")
Thank you for that idea. But why isn’t that in Base or why does it happen at all? I mean I don’t want to wrap the sleep method all the time
---
### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [June 14, 2024, 12:10pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/9 "2024-06-14T12:10:21Z")
This should get a better error message. The error is thrown here:
>
Which triggers in this case:
>
So this throws `EOFError` if the timer has already expired i.e. the sleeping duration is too short.
---
### Author:  [@ericphanson](https://discourse.julialang.org/u/ericphanson)
#### Post date: [June 14, 2024, 12:39pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/10 "2024-06-14T12:39:11Z")
It seems like for `sleep` the code should be modified so no error is thrown in that case. It doesn’t seem helpful to error if it “overslept”, in fact that seems expected in some cases.
---
### Author:  [@stevengj](https://discourse.julialang.org/u/stevengj)
#### Post date: [June 14, 2024, 1:04pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/11 "2024-06-14T13:04:50Z")
> [@ericphanson](#):
>
> It seems like for `sleep` the code should be modified so no error is thrown in that case. It doesn’t seem helpful to error if it “overslept”, in fact that seems expected in some cases.
>
>
> This prevents \`sleep\` from throwing an \`EOFError\` under rare conditions (with ve…ry short timer durations) where the \`Timer\` object is already closed before it can be signaled, which seems like a bug.
>
> See \[the discourse discussion\](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394).
---
### Author:  [@SunnyUser](https://discourse.julialang.org/u/SunnyUser)
#### Post date: [June 27, 2024, 11:59am UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/12 "2024-06-27T11:59:04Z")
If the issue was the duration being too short, we would expect the following code to throw an error as the timer `t` has already expired by the time we wait for it. But it does not.
```julia
julia> t = Timer(1); sleep(2); wait(t)
julia>
```
---
### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [June 27, 2024, 1:10pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/13 "2024-06-27T13:10:38Z")
> [@SunnyUser](#):
>
> If the issue was the duration being too short, we would expect the following code to throw an error as the timer `t` has already expired by the time we wait for it. But it does not.
`wait` on a `Timer` is guaranteed not to return until the `Timer` is expired and the `Timer` has not yet told anyone that it has expired (or its been told that it has expired through `close`). In other words, if `t` has already expired when the first `wait` call occurs, `wait` just notes that down atomically and returns immediately. Subsequent calls to `wait` on the same object throw, since the timer has already notified the program that it has expired:
```julia
julia> t = Timer(1); sleep(2);
julia> isopen(t)
false
julia> wait(t) # first time someone waits on this specific Timer
julia> wait(t) # second time someone waits on this specific Timer
ERROR: EOFError: read end of file
Stacktrace:
[1] wait(t::Timer)
@ Base ./asyncevent.jl:159
[2] top-level scope
@ REPL[16]:1
```
The error message is maximally unhelpful here, and I agree that this should throw on the first `wait` too. As I understand it, this behavior is part of the buggy behavior mentioned [in the linked PR](https://github.com/JuliaLang/julia/pull/54801#issuecomment-2171994543).
---
### Author:  [@SunnyUser](https://discourse.julialang.org/u/SunnyUser)
#### Post date: [June 27, 2024, 1:12pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/14 "2024-06-27T13:12:51Z")
>
>
> We will no longer throw a error if the timer fires after we first checked set.
> …
> But still keeps this case functional:
> \`\`\`
> julia\> t = Timer(1000000000);
>
> julia\> close(t)
>
> julia\> t.set
> false
>
> julia\> wait(t)
> ERROR: EOFError: read end of file
> Stacktrace:
> \[1\] wait(t::Timer)
> @ Base .\\asyncevent.jl:159
> \[2\] top-level scope
> @ REPL\[16\]:1
> \`\`\`
---
### Author:  [@ufechner7](https://discourse.julialang.org/u/ufechner7)
#### Post date: [June 27, 2024, 1:58pm UTC](https://discourse.julialang.org/t/how-can-sleep-0-001-error/113394/15 "2024-06-27T13:58:29Z")
The sleep function is not really intended for a duration of 1ms. If you need to sleep for less than 5 ms, try using sleep\_ms()` from the Timers.jl package. Or use Libc.systemsleep() which is still better than sleep() .