//SHMServer.C#include <sys/types.h>#include <sys/ipc.h>#include <sys/shm.h>#include <stdio.h>#include <stdlib.h>
#define MAXSIZE 27
void die(char *s){ perror(s); exit(1);}
int main(){ char c; int shmid; key_t key; char *shm, *s;
key = 5678;
if ((shmid = shmget(key, MAXSIZE, IPC_CREAT | 0666)) < 0) die("shmget");
if ((shm = shmat(shmid, NULL, 0)) == (char *) -1) die("shmat");
/* * * Put some things into the memory for the * other process to read. * */ s = shm;
for (c = 'a'; c <= 'z'; c++) *s++ = c;
/* * Wait until the other process * changes the first character of our memory * to '*', indicating that it has read what * we put there. */ while (*shm != '*') sleep(1);
exit(0);}
//SHMClient.C
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
#include <stdlib.h>
#define MAXSIZE 27
void die(char *s)
{
perror(s);
exit(1);
}
int main()
{
int shmid;
key_t key;
char *shm, *s;
key = 5678;
if ((shmid = shmget(key, MAXSIZE, 0666)) < 0)
die("shmget");
if ((shm = shmat(shmid, NULL, 0)) == (char *) -1)
die("shmat");
//Now read what the server put in the memory.
for (s = shm; *s != '\0'; s++)
putchar(*s);
putchar('\n');
/*
*Change the first character of the
*segment to '*', indicating we have read
*the segment.
*/
*shm = '*';
exit(0);
}
