[haiku-development] Re: A BMessage w/o a BApplication?
- From: Pete Goodeve <pete.goodeve@xxxxxxxxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Sun, 29 Jan 2012 15:31:09 -0800
On Sun, Jan 29, 2012 at 06:55:49PM +0100, fano il primo wrote:
> Ahh I *DO love* this API!
Me too... (:-), but...
>
> Let's see if I've understood correctly, sirs:
I think some important details got skipped in the replies so far.
The thing is, I don't think you can use a BLooper in your suggested
application. A Blooper is pretty much what it says it is -- it loops through
its code contimually -- *but* it waits at the beginning of each loop for
a BMessage to arrive. It really is only intended for doing something
in response to BMessages.
If you want to wait for something else -- e.g. a network event -- it will
clash with BLooper's normal wait scheme. If the looper is waiting for
a BMessage, it won't see the network event, and if you have added code
in the loop to wait for a network event, it won't be responding to
BMessages at that point.
So basically your network thread has to work the other way round.
It should loop (not a BLooper -- just use a 'while' or whatever is
appropriate) but wait with a 'select' or whatever [sorry -- I've forgotten
most of what I might have once known about sockets] for the network.
So you can't directly send a BMessage to that thread. You would have
to send an interrupt signal to the thread to get out of the select and
handle the new information in some convenient way. I suspect you
could just fill in a data block (even create a BMessage to be accessed
directly -- via pointer, not MessageReceived) before sending the signal.
OTOH, you can always send a BMessage *from* your thread *to* 'be_app'
or any other BLooper. Either have a pointer to the looper, and
directly do:
looper->PostMessage(msg);
or use a BMessenger and its SendMessage(). The former is simpler
if you're *sure* your looper exists, but the latter is a bit safer.
-- Pete --
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