Re: [MIT-Scheme-devel] Linking with the new FFI on Mac OS

[Matt Birkholz]

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On Thu, 2019-02-28 at 04:01 +0000, Joel T Gustafson wrote:
> Hello all!
> 
> I'm trying to update some foreign Scheme libraries [1] I wrote a
> while ago

I took a peek at your PortAudio wrapper because... IO is hard.

You are perhaps aware of the limitations of our simple FFI.  The
cooperatively multi-scheme-threaded world is "blocked" while in a
callout and callbacks do not change this.  Our callbacks are more like
traps, running while the whole world waits, in the thread that called
out.

Thus you cannot do schemely IO in a callback -- the kind of IO that
suspends a scheme thread that would have blocked and runs another.  At
best you might do some IO with low-level primitives knowing that, if
it is blocking IO, the whole world will be waiting.

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=/oba
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