About IPC, max size of message and queue

About IPC, max size of message and queue

Post by Cookie » Wed, 31 Mar 1999 04:00:00



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.

 
 
 

About IPC, max size of message and queue

Post by Sascha Bohnenkam » Wed, 31 Mar 1999 04:00:00


Quote:>max queues system wide = 128

max 128 messages are allowed to be waiting, e.g. the next message_send will
block if 128
messages are already waiting ...

Quote:>max size of message (bytes) = 4056

a message is allowed to have 4056 bytes of data ...
that is posix, if you need more -- fix your programm to work with it to make
it portable!

Quote:>default max size of queue (bytes) = 16384

one queue is allowed to carry as many messages as fit into 16384 bytes ...
e.g. 4 full-sized messages

Quote:>I'd like to know each number what's it mean ?

see above

Quote:> And can I change them ?

yes --- you have the linux-source, you can change anything

Quote:>Or where can I get this detail ?

Stevens: Advanced Programming in the Unix Environment

Quote:>Because I fear size of my structure of message is over max size of
>message.

split your structures and transmit those pieces

 
 
 

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