C Posix queues message size

[jimbo7777]

Hi Folks,

What are the message limits for mq_open() system call? I.e. What is the max size of bytes on message (mq_msgsize attr)? What is max number of posix queues mq_maxmsg attr?

Where can I configure these limits?

Thanks a lot in advance,
Madars

 

[jimbo7777]

In my case I cannot run messages bigger with than 32KB, then I get invalid argument error from mq_open.

 

[mrclksr]

Hi jimbo7777 ,

What is the max size of bytes on message (mq_msgsize attr)? What is max number of posix queues mq_maxmsg attr?

The system wide default values for mq_maxmsg and mq_msgsize are 100 and 16384 respectively.

Where can I configure these limits?

These values can be altered by using the sysctl variables kern.mqueue.maxmsg and kern.mqueue.maxmsgsize.