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Re: Restrictions

This page is part of the web mail archives of SRFI 50 from before July 7th, 2015. The new archives for SRFI 50 contain all messages, not just those from before July 7th, 2015.



Am Tue, 06 Jan 2004 08:35:29 +0100 hat Michael Sperber <sperber@xxxxxxxxxxxxxxxxxxxxxxxxxxx> geschrieben:

"Felix" == Felix Winkelmann <felix@xxxxxxxxxxxxx> writes:

Felix> Michael Sperber wrote:

felix> Note that the Chicken FFI (for example) does not allow GC during the
felix> invocation of foreign code,

Sure, and that *greatly* simplifies a lot of issues.  It's also an
unacceptable restriction for many Scheme systems.

Felix> Well, I wonder what that should be. Could you provide an example?

Any environment where

- C code allocates
- allocation may trigger a GC to provide the requested space

Huh? Then perform a callback. Where's the problem?

(BTW, if you re-read the message you're quoting, it says:

"Note that the Chicken FFI (for example) does not allow GC during the invocation of foreign code,
 unless callbacks are explicitly used"
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)


These include, at the very least:

- Scheme 48
- scsh
- MzScheme
- Gambit-C
- Elk

(In case you completely misunderstood: Chicken allows callbacks.
Callbacks may allocate, allocation may GC, i.e. C code called in Chicken
may GC)


PS: Please note this is SRFI 50; you posted to the SRFI 40 mailing
    list


Yep, sorry. I noticed two seconds too late and reposted it.


cheers,
felix