moonbit-num-cpus is a small MoonBit module for detecting the number of CPU cores available on the current machine.

It supports:

• Logical CPU count, including SMT / hyper-threading
• Physical CPU count when the operating system can report it
• Native implementations for Windows, macOS, Linux, and other Unix-like systems
• Safe fallback behavior that never returns less than 1

moon add justjavac/num_cpus

fn main {
  let logical = @num_cpus.get()
  let physical = @num_cpus.get_physical()

  println("Logical CPU cores: \{logical}")
  println("Physical CPU cores: \{physical}")

  if logical > physical {
    println("SMT or hyper-threading is likely enabled")
  }
}

fn worker_count() -> Int {
  @num_cpus.get_physical()
}

fn main {
  let logical = @num_cpus.get()
  let physical = @num_cpus.get_physical()
  println("CPU topology: \{physical} physical / \{logical} logical")
}

• Logical CPU detection uses native platform APIs rather than external commands.
• Physical CPU detection uses the best available system interface on each OS.
• When physical core detection is unavailable, the module falls back to the logical CPU count.
• The package is designed for the native target and declares it as the preferred target.

moon test --target native
moon check --deny-warn --target native

MIT. See LICENSE.

Inspired by Rust's num_cpus crate.