On Thursday, 5 de January de 2012 12.07.37, craig.sc...@csiro.au wrote: > On 05/01/2012, at 11:47 AM, Thiago Macieira wrote: > > On Thursday, 5 de January de 2012 11.03.42, craig.sc...@csiro.au wrote: > >> This could be perceived as creating a race condition. You'd have to > >> connect > >> a slot to the signal on the object returned, but what if the signal is > >> emitted before you get a chance to do that? > > > > It cannot happen if you make it, by design, not possible. > > > > That means the reply object must ensure that it never processes replies > > before first returning to the user. If a result was found cached (if ever > > there's a cache), then we need to be able to tell the user that the reply > > has already finished. > > Even if it never processes replies before first returning the user, there is > the possibility of a race condition:
No, there isn't. Your scenario below implies the user willfully connected
late. All you need to do is connect the signal before returning to the event
loop. That's how QNetworkReply ensures it works.
> (1) Reply object is returned to the user.
> (2) Reply object processes the request and emits the relevant finished
> signal in its own thread.
> (3) Caller adds a signal-slot connection (could
> be on the line immediately following the function call that returned the
> reply object), but the signal has already been missed.
--
Thiago Macieira - thiago.macieira (AT) intel.com
Software Architect - Intel Open Source Technology Center
Intel Sweden AB - Registration Number: 556189-6027
Knarrarnäsgatan 15, 164 40 Kista, Stockholm, Sweden
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