devctl messages, return data with pointers

QNX Newsgroups (Archives) qnx.ddk
1

Hi all,

I have test application and resouce manager and I use devctlv to send
some data with pointers from application to resouce manager and in
this way work ok.But I also need to return some pointer data from
resouce manager to the test application.It is possible to do and how
can I solve this problem?

Thanks

Juraj

2

I’m not sure what use pointers would be between separate processes,
unless you are using shared memory, but in any case, with message
passing data goes both ways. Likewise devctl can receive and send
back data. Are you having trouble getting devctl to work right?
Make sure you are using the right macros to define your commands.

3

hi,
I use devctlv not devctl because of data with pointers.devctlv is
proposed to handle structure data with some pointers inside.In
resouce manager I can read this data which was send from test
application in call back function.But I don’t know how to send return
data back to the test application.

Thanks

Juraj

4

That’s interesting. I can’t find devctlv in the Help on 6.3.3?

5

juro <juraj.frank@naex-dot-sk.no-spam.invalid> wrote:

hi,
I use devctlv not devctl because of data with pointers.devctlv is
proposed to handle structure data with some pointers inside.In
resouce manager I can read this data which was send from test
application in call back function.But I don’t know how to send return
data back to the test application.

Just MsgReply() with the io_devctl_reply header followed by the data
that you want to return. (Or, MsgReplyv().)

-David

David Gibbs
QNX Training Services
dagibbs@qnx.com