Detecting if Mac has a backlit keyboard-CodePudding

It’s quite easy to detect if Mac has an illuminated keyboard with ioreg at the command line…

ioreg -c IOResources -d 3 | grep '"KeyboardBacklight" =' | sed 's/^.*= //g'

…But how can I programmatically get this IOKit boolean property using the latest Swift? I’m looking for some sample code.

CodePudding user response：

I figured out the following with some trial and error:

Get the "IOResources" node from the IO registry.
Get the "KeyboardBacklight" property from that node.
(Conditionally) convert the property value to a boolean.

I have tested this on an MacBook Air (with keyboard backlight) and on an iMac (without keyboard backlight), and it produced the correct result in both cases.

import Foundation
import IOKit

func keyboardHasBacklight() -> Bool {
    let port: mach_port_t
    if #available(macOS 12.0, *) {
        port = kIOMainPortDefault // New name as of macOS 12
    } else {
        port = kIOMasterPortDefault // Old name up to macOS 11
    }
    let service = IOServiceGetMatchingService(port, IOServiceMatching(kIOResourcesClass))
    guard service != IO_OBJECT_NULL else {
        // Could not read IO registry node. You have to decide whether
        // to treat this as a fatal error or not.
        return false
    }
    guard let cfProp = IORegistryEntryCreateCFProperty(service, "KeyboardBacklight" as CFString,
                                                       kCFAllocatorDefault, 0)?.takeRetainedValue(),
          let hasBacklight = cfProp as? Bool
    else {
        // "KeyboardBacklight" property not present, or not a boolean.
        // This happens on Macs without keyboard backlight.
        return false
    }
    // Successfully read boolean "KeyboardBacklight" property:
    return hasBacklight
}