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#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <stdio.h>
#define MSGSZ 128
#ifdef NOT_USED
/*
* Declare the message structure.
*/
struct msgbuf {
long mtype;
char mtext[MSGSZ];
};
#endif /* NOT_USED */
main()
{
int msqid;
key_t key;
struct msgbuf sbuf, rbuf;
/*
* Create a message queue with "name" 1234.
*/
key = 1234;
/*
* We want to let everyone read and
* write on this message queue, hence
* we use 0666 as the permissions.
*/
if ((msqid = msgget(key, IPC_CREAT | 0666)) < 0) {
perror("msgget");
exit(1);
}
/*
* Receive a message.
*/
if (msgrcv(msqid, &rbuf, MSGSZ, 0, 0) < 0) {
perror("msgrcv");
exit(1);
}
/*
* We send a message of type 2.
*/
sbuf.mtype = 2;
sprintf(sbuf.mtext, "I received your message.");
/*
* Send an answer.
*/
if (msgsnd(msqid, &sbuf, strlen(sbuf.mtext) + 1, 0) < 0) {
perror("msgsnd");
exit(1);
}
exit(0);
}
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