Detect if force touch is supported through IOKit

iokit_forcetouch.c

#include <IOKit/hid/IOHIDLib.h>
#include <IOKit/hid/IOHIDEventSystem.h>

int main(int argc, char **argv, char **envp) {

	CFMutableDictionaryRef dict = IOServiceMatching("AppleMultitouchN1SPI");
	CFDictionaryAddValue(dict, CFSTR(kIOHIDManufacturerKey), CFSTR("Apple Inc."));

	io_iterator_t iter;
	mach_port_t port = kIOMasterPortDefault;
	IOServiceGetMatchingServices(port, dict, &iter);

	io_object_t device = 0;
	while ((device = IOIteratorNext(iter)))
	{
		CFMutableDictionaryRef result = NULL;
		kern_return_t err = IORegistryEntryCreateCFProperties(device, &result, kCFAllocatorDefault, 0);
		if (err == KERN_SUCCESS && result != NULL) {

			CFTypeRef forceEnabled = NULL;
			CFDictionaryGetValueIfPresent(result, CFSTR("ForceSupported"), &forceEnabled);
			if (forceEnabled) {

				NSLog(@"Force touch is supported!");

			}  

		}

		IOObjectRelease(device);
	}

	IOObjectRelease(iter);

	return 0;
}