[PD-dev] Same buffer for input and output?

[Evan Buswell]

Hello,

I'm new to the community so apologies if this isn't the best place to post
this. I'm currently working on a pd external that's wrapping an synthesis
library I've been working on for a few years. I'll share it when it's in
working shape, but it may not be of interest as the library is not
specifically tailored to pd and so there's a lot of redundancy with other
people's work.

I've noticed that sometimes input and output buffers will be identical,
e.g. logging the arguments from a lowpass filter, I get: *filter=0x261ab0,
n=64, *y=0x32a360, *x=0x329fd0, *f=0x32a100, *Q=0x32a360 -- meaning that Q
and y share the same buffer. This leads to weird results when history (i.e.
x[i-1], x[i-2], etc.) is needed. My questions are: is this intentional?
why? is this sharing somehow deterministic? can it somehow be
deterministically disabled with a flag somewhere? There are multiple
workarounds, of course, but I figured I'd ask first.

Thanks for your help,

Evan
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