On 04.12.2011 09:10, Marco Leise wrote:
Am 03.12.2011, 19:47 Uhr, schrieb Andrej Mitrovic
<andrej.mitrov...@gmail.com>:
On 12/3/11, Marco Leise <marco.le...@gmx.de> wrote:
Am 03.12.2011, 19:05 Uhr, schrieb Andrej Mitrovic
<andrej.mitrov...@gmail.com>:
+1 on interest on having this. Back when I was attempting to port VST
to D I got asked by a Steinberg dev how I can guarantee that D plugins
will work. But I couldn't guarantee it, if a GC collection were to run
the plugin would freeze, the host would crash, and the host company
would likely get the blame.
You'll get some angry comments on this one by others. I'll lean back and
enjoy the show :D
I don't follow..?
Hmm, and no one commented either. I thought someone would jump in and
say that you could disable the GC and that malloc isn't realtime either
and for that reason the host application should not crash when a plugin
doesn't deliver in time. The audio should stutter and that's it. So: no
realtime guarantees whatsoever on consumer OSs, but a high probability
that it will just work.
Indeed, malloc is not real-time safe. It is common wisdom that real-time
audio code should not handle any memory allocations.
To this point, D is just as safe as C++: don't do any operations that
may allocate memory in the audio thread, so the GC will never be invoked
in real-time critical code.
Where it gets more involved, though, is that D garbage collection is not
thread safe. When it starts, all registered threads are stopped.
Note: the audio-thread is typically created externally with special
settings, so D will not know about it and the GC will not stop it. As
long as the audio-thread never does any pointer assignments that are
relevant to the GC, everything should be safe.
Just make sure that any garbage collected objects that the audio thread
accesses have live pointer from areas that the GC knows about. That way
it will not matter whether the GC scans the audio-data or not or whether
this data is modified by the audio-thread while the GC is scanning it.
