Inter process Communication

QNX Newsgroups (Archives) qdn.public.porting
1

Hi

I’m trying to implement an inter process communication system using message
queues under Neutrino.
My first question is about mq_attr.mq_flags . In Qnx 4 you could use
MQ_NOTIFY_ALWAYS but it seems that this has disappeared , do you know why ?
Moreover i’m trying to get a notification when receiving data in that queue
via a signal handler but it seems that this handler is never called . I have
used SIGEV_SIGNAL_CODE_INIT and tried also to fill the sigevent myself ,
both fails. When i send the signal i’m waiting for ( SIGUSR1) the handler is
called. Qny clues ?

Thanks.


Christophe.

2

Christophe Menard <christophe.menard@voila.fr> wrote:

Hi

I’m trying to implement an inter process communication system using message
queues under Neutrino.
My first question is about mq_attr.mq_flags . In Qnx 4 you could use
MQ_NOTIFY_ALWAYS but it seems that this has disappeared , do you know why ?

Not Posix. Also, not really needed if you do your notification properly.
When you get notification, re-enable notification, THEN drain the queue.

Moreover i’m trying to get a notification when receiving data in that queue
via a signal handler but it seems that this handler is never called . I have
used SIGEV_SIGNAL_CODE_INIT and tried also to fill the sigevent myself ,
both fails. When i send the signal i’m waiting for ( SIGUSR1) the handler is
called. Any clues ?

Are you actually getting notification at all? That is, do you ever hit
a notification condition?

-David

QNX Training Services
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