// Copyright (c) 2026 Charles KWON OhJun (charleskwonohjun@gmail.com)
// All rights reserved.

//go:build darwin || linux

package hbrtl

import "os"

// openFDCount reads /dev/fd (macOS) or /proc/self/fd (Linux). Returns -1
// if the directory can't be listed — Windows falls back to the stub.
func openFDCount() int {
	for _, path := range []string{"/proc/self/fd", "/dev/fd"} {
		f, err := os.Open(path)
		if err != nil {
			continue
		}
		names, err := f.Readdirnames(-1)
		f.Close()
		if err == nil {
			return len(names)
		}
	}
	return -1
}