msgctl & Max Message Queue Size

msgctl & Max Message Queue Size

Post by Christopher Miln » Fri, 16 Jun 1995 04:00:00

Hi all,

When I create a Solaris Message Queue using msgctl(), its default size is
4096 bytes.

I'd like to increase the size of the queue by setting the msg_qbytes member of the
struct msgqid_ds structure to, say, 40K bytes, and call msgctl again (with IPC_SET).

Problem is, whenever I try to increase the size of the queue, msgctl fails with

Am I allowed to increase the size?  Must I be root?  Must I have been granted certain
permissions by root?  Does the O/S support larger message queues?  One would think so..

Thanks for your input,

Chris Milner


1. About IPC, max size of message and queue

    Now I'm coding a program that use in my job and use message queue
for communication data. I ran 'ipcs -l' command :

This's result.

------ Messages: Limits --------
max queues system wide = 128
max size of message (bytes) = 4056
default max size of queue (bytes) = 16384

I'd like to know each number what's it mean ? And can I change them ?
Or where can I get this detail ?
Because I fear size of my structure of message is over max size of

Thanks for your help.
Kritsada Poolwan.

2. newbie & wine



5. Max number of char in Message Queues

6. ISDN and Linux

7. Message Queues max. limit?

8. Thinkpad Soundcard

9. max number processes, message queues

10. max number of processes, message queues

11. Sendmail Max messages size

12. Max size of a message for msgsnd()

13. MSGMAX - SunOS max message size 2048?