compileOption("threads") never be false within NimScript

[panno8M]

Nim Version

$ nim -v
Nim Compiler Version 2.2.2 [Linux: amd64]
Compiled at 2025-02-06
Copyright (c) 2006-2025 by Andreas Rumpf

git hash: 6c34f62785263ad412f662f3e4e4bf8d8751d113
active boot switches: -d:release

Description

The value of compileOption(“threads”) is always true within NimScript even if passing --threads:off.

This may be due to the fact that NimScript is actually running in multi-threaded mode, but it is a little inconvenient for building a build system.

# config.nims
echo compileOption("threads")

$ nim c --threads:off somewhat

Current Output

true

Expected Output

false

Known Workarounds

No response

Additional Information

No response

[Araq]

Agreed, but it raises the question if --threads:off is a switch worth keeping. Every switch technically creates a new language dialect and that causes problems for everybody and every tool.

[panno8M]

If Nim does not plan to add a new backend in the future, no, I think.
Some potential Nim backends may have unstable multi-threaded support.
No other motive comes to mind for me either.

Context (No need to read):

I noticed this behavior because I was trying to get WebAssembly (wasm) with emscripten as a backend.
I was warned because multi-threading was an experimental feature in emscripten. So I am now trying to switch pipelines depending on the value of threads.