macOS. How to get CPU temperature programmatically

I need to get CPU temperature using Swift, but I can't find any information except for this.

I think that I should use IOKit.framework but again there's no much information about it.

Solution

using https://github.com/lavoiesl/osx-cpu-temp/blob/master/smc.c I got it to work. You have to do a few things:

Simplify main() to something else:

double calculate()
{
    SMCOpen();
    double temperature = SMCGetTemperature(SMC_KEY_CPU_TEMP);
    SMCClose();
    temperature = convertToFahrenheit(temperature);
    return temperature;
}

Write an ObjC wrapper:

#import "SMCObjC.h"
#import "smc.h"   
@implementation SMCObjC

+(double)calculateTemp {
    return calculate();
}

@end

Add the header to your Swift bridging header.

//
//  Use this file to import your target's public headers that you would like to expose to Swift.
//
#import "SMCObjC.h"

If the app is sandboxed, add a security exemption for AppleSMC:

<dict>
    <key>com.apple.security.app-sandbox</key>
    <true/>
    <key>com.apple.security.files.user-selected.read-only</key>
    <true/>
    <key>com.apple.security.temporary-exception.sbpl</key>
    <array>
        <string>(allow iokit-open)</string>
        <string>(allow iokit-set-properties (iokit-property &quot;AppleSMC&quot;))</string>
        <string>(allow mach-lookup (global-name &quot;com.apple.AssetCacheLocatorService&quot;))</string>
    </array>
</dict>
</plist>

Call it from Swift.

import Cocoa

class ViewController: NSViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        let temp = SMCObjC.calculateTemp()
        print("I got \(temp) in swift")
    }
}