# How to avoid multiple \_\_init\_\_ calls?

**URL:** <https://discourse.julialang.org/t/how-to-avoid-multiple-init-calls/139531>\
**Category:** General Usage\
**Created:** [September 18, 2026, 4:11am UTC](https://discourse.julialang.org/t/how-to-avoid-multiple-init-calls/139531 "2026-09-18T04:11:39Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Alex1](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/alex1/32/11771_2.png) [@Alex1](https://discourse.julialang.org/u/Alex1)\
**Post date:** [September 18, 2026, 4:11am UTC](https://discourse.julialang.org/t/how-to-avoid-multiple-init-calls/139531/1 "2026-09-18T04:11:40Z")

</div>

I use project wide config used by many modules. And sometimes I observe its ` __init__ ` function called many times, I assume during compilation.

How to avoid that is the proper way to use `ccall(:jl_generating_output, Cint, ()) == 1 && return nothing`?

The config

```julia-auto
module Config

now::Date = Date(0)

const clear_cache_cbs = Function[]
clear_cache!() = for cb in clear_cache_cbs; cb() end
clear_cache!(cb::Function) = push!(clear_cache_cbs, cb)

set_now(d::Date) = begin
  Config.now == d && return
  Config.now = d
  clear_cache!()
  @info "config" (; now=Config.now)
end

add_load_path!(p) = begin
  p = realpath(p); p ∉ LOAD_PATH && push!(LOAD_PATH, p)
end

__init__ () = begin
  # ccall(:jl_generating_output, Cint, ()) == 1 && return nothing

  set_now(haskey(ENV, "now") ? Date(ENV["now"]) : Date(Dates.now(UTC)))
  haskey(ENV, "now") && @warn "config" (; now=Config.now)

  add_load_path!("$(@ __DIR__ )/reports")
  add_load_path!("$(@ __DIR__ )/lib")
  add_load_path!("$(@ __DIR__ )/SV")
  add_load_path!("$(@ __DIR__ )/options")
  add_load_path!("$(@ __DIR__ )/garch")
end

end

```

---

<div class="post-metadata">

**Author:** ![GunnarFarneback](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gunnarfarneback/32/1827_2.png) [@GunnarFarneback](https://discourse.julialang.org/u/GunnarFarneback)\
**Post date:** [September 18, 2026, 6:53am UTC](https://discourse.julialang.org/t/how-to-avoid-multiple-init-calls/139531/2 "2026-09-18T06:53:39Z")

</div>

I think this needs more context, e.g. on how (by which mechanism) it is used by multiple modules and what you want to achieve with the config. Manipulating `LOAD_PATH` from an ` __init__ ` function looks scary to me. There have to be better alternatives.

---

<div class="post-metadata">

**Author:** ![Alex1](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/alex1/32/11771_2.png) [@Alex1](https://discourse.julialang.org/u/Alex1)\
**Post date:** [September 18, 2026, 7:54am UTC](https://discourse.julialang.org/t/how-to-avoid-multiple-init-calls/139531/3 "2026-09-18T07:54:07Z")

</div>

The `.` added to `LOAD_PATH` in julia global startup file, and Revise.

The main.jl then can look like:

```julia
import Config # Always loaded first, it defines project paths and other settings
import SVJ # located in ./SV/SVJ.jl

println("hi")

```

Any module will be automatically loaded on demand and changes tracked and reloaded.

Config also imported (imported, not included) by many other modules, like `SVJ.jl`.

Everything loaded and reloaded automatically. No need to explicitly use include, define packages etc.

It works well, but I assume during compilation Julia reloads modules in some strange way, and `Config. __init__ ` called multiple times, I made it idempotent so it already works, but would like to fix it properly.

---

<div class="post-metadata">

**Author:** ![GunnarFarneback](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gunnarfarneback/32/1827_2.png) [@GunnarFarneback](https://discourse.julialang.org/u/GunnarFarneback)\
**Post date:** [September 18, 2026, 8:17am UTC](https://discourse.julialang.org/t/how-to-avoid-multiple-init-calls/139531/4 "2026-09-18T08:17:21Z")

</div>

I would say that the proper fix _is_ to use include, define packages, etc.

But if you absolutely don’t want to do that, you can investigate whether this new Julia 1.12 feature is of any help to you:

> `OncePerProcess{T}(init::Function)() -> T`
> 
> Calling a OncePerProcess object returns a value of type T by running the function initializer exactly once per process. All concurrent and future calls in the same process will return exactly the same value. This is useful in code that will be precompiled, as it allows setting up caches or other state which won’t get serialized.

---

<div class="post-metadata">

**Author:** ![Benny](https://avatars.discourse-cdn.com/v4/letter/b/49beb7/32.png) [@Benny](https://discourse.julialang.org/u/Benny)\
**Post date:** [September 18, 2026, 5:23pm UTC](https://discourse.julialang.org/t/how-to-avoid-multiple-init-calls/139531/5 "2026-09-18T17:23:14Z")

</div>

> [@Alex1](#):
>
> And sometimes I observe its ` __init__ ` function called many times, I assume during compilation.

` __init__ ()` shouldn’t be repeated unless it’s being explicitly called. If you mean you observe it during precompilation, that’s happening for the first times in isolated child processes. Haven’t confirmed it personally, but I think the child processes would get a new copy of the environment variables changed by `ENV` in the parent process, but `LOAD_PATH` is totally reset.

> [@Alex1](#):
>
> is the proper way to use `ccall(:jl_generating_output, Cint, ()) == 1 && return nothing`?

That is one way, but it’s usually used for different states that directly obstruct precompilation (devdocs source below), and it’s preferred to refactor or clean those states up in other ways. Like GunnarFarneback said, I’m not sure about manipulating `LOAD_PATH` to potentially import dependencies that could sidestep `Pkg.resolve`. Also not a fan of a dependency automatically tweaking `ENV`.

[Fixing precompilation hangs due to open tasks or IO · The Julia Language](https://docs.julialang.org/en/v1/devdocs/precompile_hang/)

---

<div class="post-metadata">

**Author:** ![Alex1](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/alex1/32/11771_2.png) [@Alex1](https://discourse.julialang.org/u/Alex1)\
**Post date:** [September 18, 2026, 11:54pm UTC](https://discourse.julialang.org/t/how-to-avoid-multiple-init-calls/139531/6 "2026-09-18T23:54:07Z")

</div>

> If you mean you observe it during precompilation, that’s happening for the first times in isolated child processes.

Yes, thanks, it looks like that case.

It aready works well, the main problem - misleading logs, in my case logs are important and I read it. And when something unexpected get printed it’s annoying.