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

int main()
{
   char str[256];
   size_t size = sizeof (str);

   int i;
   size_t len = sizeof(i);

   if (sysctlbyname ("kern.version", str, &size, NULL, 0)) {
      perror ("kern.version");
   } else {
       printf ("kern.version %s\n", str);
   }

   if (sysctlbyname ("kern.osrelease", str, &size, NULL, 0)) {
      perror ("kern.osrelease");
   } else {
       printf ("kern.osrelease %s\n", str);
   }

   if (sysctlbyname ("kern.osversion", str, &size, NULL, 0)) {
      perror ("kern.osversion");
   } else {
       printf ("kern.osversion %s\n", str);
   }

   if (sysctlbyname ("kern.osrevision", &i, &len, NULL, 0)) {
      perror ("kern.osversion");
   } else {
       printf ("kern.osversion %s\n", str);
   }
}