What is difference between "pulse" and "message"?

I am a a newuser of QNX and I am doing a assignment which involves some
system call in QNX,

The MsgReceive(…) system call return a value, from specification, it
saids:

0 : it is a rcvid.It encodes the sending thread’s ID and a local connection
ID.

=0: it is a pulse ,Unlike a message, your shouldn’t reply to a pulse.

What is the difference between a pulse and a message?Why the server side
should not reply a pulse?

Also, If I have some question on concurrent programming in qnx, which
newsgroup should I post to?
Thanks a lot for your help.

P.S. btw, I still don’t know how to install an editor in qnx…I can’t find
a window with an icon and double click it… I just find something like
“software installer” for qnx, but I don’t know how to use…that may be a
stupid question, ,but I do need help…hope all of you won’t mind.

()=()=()=()=()=()=()=()=()
^_^!
I ask because I am a novice.
()=()=()=()=()=()=()=()=()

What is the difference between a pulse and a message?Why the server side
should not reply a pulse?

A pulse is an asyncronous event that carries only a single 32bit value. When
the client sends a pulse it isn’t expecting a reply so there isn’t anything
for the server to reply to. Normal messages are syncronous, so the client
will always be waiting for a reply and will stop until a reply is received.

Also, If I have some question on concurrent programming in qnx, which
newsgroup should I post to?

You could post here or on our internal newsgroups @ inn.qnx.com.

P.S. btw, I still don’t know how to install an editor in qnx…I can’t find
a window with an icon and double click it… I just find something like
“software installer” for qnx, but I don’t know how to use…that may be a
stupid question, ,but I do need help…hope all of you won’t mind.

If you click on the Launch menu, go to Editors and click on Ped you will get
a basic editor. There are others you can install from the web including
Workspace, Vim, Emacs, …

chris


Chris McKillop <cdm@qnx.com> “The faster I go, the behinder I get.”
Software Engineer, QSSL – Lewis Carroll –
http://qnx.wox.org/

Chris McKillop wrote:

If you click on the Launch menu, go to Editors and click on Ped you will get
a basic editor. There are others you can install from the web including
Workspace, Vim, Emacs, …

Don’t forget eclipse (from www.eclipse.org).

Rennie

Shirley <novice@hongkong.com> wrote:

I am a a newuser of QNX and I am doing a assignment which involves some
system call in QNX,

The MsgReceive(…) system call return a value, from specification, it
saids:

0 : it is a rcvid.It encodes the sending thread’s ID and a local connection
ID.
=0: it is a pulse ,Unlike a message, your shouldn’t reply to a pulse.

What is the difference between a pulse and a message?Why the server side
should not reply a pulse?

I’d strongly suggest taking a read through the System Architecture
manual, in particular, Chapter 2, “The QNX Neutrino Microkernel”,
subsection, “QNX Neutrino IPC”.

In essence, on the send side of a message (MsgSend), it will not
return (complete) until the server side receives the message
(MsgReceive) and replies with a result or reply message (MsgReply).

For a pulse, the delivery call (MsgSendPulse) returns immediately,
queueing the pulse for delivery, when the pulse is delivered, the
receive returns, but there is no-one waiting for a reply, so no
reply is needed, nor can be done.

Also, If I have some question on concurrent programming in qnx, which
newsgroup should I post to?

This newsgroup is good, but again… the documentation, especially the
System Architecture guide, is very worthwhile to read before getting
into things.

-David

QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.