Very Computer

by **Michael Mandelber** » Sat, 28 Oct 2000 22:58:51

Sorry if this belongs elsewhere. If so, I'd appreciate a pointer.

I am trying to use the IPC message queue on Redhat 6.2. Here's my code

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <stdio.h>

#define TM_MSGQ_KEY 1000

typedef struct TM_MSGBUF
{
long mtype;
char mtext[20];
}a;

int main()
{

int tm_msqId = msgget( TM_MSGQ_KEY, 0666 | IPC_CREAT );

TM_MSGBUF bufsnd={100,"Hope this works"}, bufrcv;
bufsnd.mtype = 100;

printf("send buffer type = %d\n",bufsnd.mtype);
printf("send buffer data = %s\n\n\n",bufsnd.mtext);

msgsnd(tm_msqId, (struct msgbuf *)&bufsnd, sizeof(bufsnd), 0);
msgrcv(tm_msqId,(struct msgbuf *)&bufrcv,sizeof(bufrcv), 0, 0);

printf("send buffer type = %d\n",bufsnd.mtype);
printf("send buffer data = %s\n\n\n",bufsnd.mtext);

printf("receive buffer type = %d\n",bufrcv.mtype);
printf("receive buffer data = %s\n\n\n",bufrcv.mtext);
}
And here's the output:

send buffer type = 100
send buffer data = Hope this works

send buffer type = 0
send buffer data = Hope this works

receive buffer type = 100
receive buffer data = Hope this works

The problem is that the message type in bufsnd has been corrupted. Any
ideas what's going on here?

Thanks

Michael Mandelberg

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