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
errno=EPERM.

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

Dear,
    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
message.

Thanks for your help.
Kritsada Poolwan.

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