#include <stdio.h>
#include <stdlib.h>

#include <sys/types.h>
#include <sys/mman.h>

int
main(int argc, char *argv[])
{
        void *ptr;
        pid_t pid;
        size_t amt;
        int wstat;

        amt=(size_t) (1 * sizeof(char));
        ptr = malloc(amt);

        printf("pre-lock: %p\n", ptr);
        mlock(ptr,amt); 

        if((pid = fork()) == 0) {
                sleep(1);
                printf("child: %p\n", ptr);
                return 0;
        }
        else {
                printf("parent: %p\n", ptr);
                waitpid(pid, &wstat);
        }

        return 0;

}