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

/* This max value is related to the depth value of the oid.
   For example the leaf life in hw.acpi.battery.life is at depth 4 */
#define MAX_DEPTH 10

int main (int argc, char *argv[])
{
        int mib[MAX_DEPTH], len = MAX_DEPTH;
        int result;
        unsigned value;

        result = sysctlnametomib ("hw.acpi.battery.life", mib, &len);
        if (result == -1)
        {
                perror ("sysctlnametomib");
                exit (-1);
        }

        len = sizeof(value);
        result = sysctl (mib, 4, &value, &len, NULL, 0);
        if (result == -1)
        {
                perror ("sysctl");
                exit (-1);
        }

        printf ("value = %d\n", value);
        return 0;
}