#include <sys/types.h>
#include <sys/sysctl.h>
#include <stdio.h>

#define	KELV_ZEROC	2732
#define	KELV_TO_CEL(x)	((x) - KELV_ZEROC)
#define	CEL_TO_FAR(x)	((x) * 9 / 5 + 320)
#define KELV_TO_FAR(x)	CEL_TO_FAR(KELV_TO_CEL((x)))

int
main(int ac, char **av)
{
	int celsius, far, kelvin, error;
	size_t kelvinlen = sizeof(kelvin);

	/*
	 * Use sysctl interface to get temperature.
	 */
	error = sysctlbyname("hw.acpi.thermal.tz0.temperature", &kelvin,
	    		&kelvinlen, NULL, 0);
	if (error == -1)
		err(1, "sysctlbyname (hw.acpi.thermal)");
	
	celsius = KELV_TO_CEL (kelvin);
	far = CEL_TO_FAR (celsius);
	printf("ACPI Thermal Zone Information\n");
	printf("System temperature = %d.%d K  %d.%d C  %d.%d F\n", kelvin / 10,
	    kelvin % 10, celsius / 10, celsius % 10, far / 10, far % 10);
}