hi,all
i have in trouble about msgget.
i create a queue and the program like blow:

openMsg( pid_t key )
{
....
int msgid;
....
msgid=msgget(key,IPC_CREAT|IPC_EXCL|0666)
if( msgid<=0 ){
fprintf( stdout,"%s,%d",strerror(errno),errno );
return -1;
}
else{
return msgid;
}
}

when i open my computer and run this program first ,the answer always is "Invalid argument" .
use ipc to see the queue stat, i found a queue is already exist just like this
"Message Queues
q 0 0x00000835 --rw-rw-rw- iccard informix
"
when i delete the queue ,and restart my program ,everything right.
so why? please tell me.
thank you.

Hi!

It may be because you are not deleting the "Message Queue" before exiting your application. You should be using the command IPC_RMID in your shmctl() function to remove the Message Queue before exiting your program.

Regards
SHAIK

the queue not exist before i run this program.

What is the value of key ?

the key is 2101

Are you sure you are getting the Error Message "Invalid argument" for this msgget()? Maybe the error is on some other function like: msgctl() or msgsnd() or msgrcv() . . .

yes, i'm sure.
because i have log file and trace the problem.