#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
#include <strings.h>

int main()
{int shmid,i;
 char *shmptr;
 /* Get a 10 byte shared memory segment */
 shmid=shmget(getuid(),10,IPC_CREAT|0600);
 fprintf(stderr,"Shmem ID: %d\n",shmid);
 shmptr=shmat(shmid,0,0);
 strcpy(shmptr,"0123456789");
 fprintf(stderr,"Shmem Contents: %s\n",shmptr);
 /* use realloc to change size */
 realloc(shmptr,11); 
 fprintf(stderr,"Shmem Contents after realloc: %s\n",shmptr);
 shmctl(shmid,IPC_RMID,0);
}