[gambit-list] Passing lambdas as callbacks to C functions
pdawes at users.sf.net
Sat Feb 3 02:57:09 EST 2007
Actually, here's a testcase that's more representative of what I'm
trying to do:
(c-define (call-lambda l) (scheme-object) void "call_lambda" ""
(c-lambda (scheme-object) void
(let ((e 1))
(lambda () (set! e 2)))))
It seems that modifying state outside the lambda causes it to crash
(after looping a few times). This time I get:
*** ERROR IN looper -- Operator is not a PROCEDURE
..which strikes me as a corrupted memory sort of error since I'm not
doing anything with meroon.
Any pointers would be much appreciated.
Phil Dawes wrote:
> Hi Marc, Hi Gambit List,
> I ran into problems using lambda expressions as callbacks when wrapping
> libcsv and I've boiled it down to this testcase. Can anybody tell me why
> this crashes?:
> (c-define (call-lambda l) (scheme-object) void "call_lambda" ""
> (define looper
> (c-lambda (scheme-object) void
> (define (main)
> (looper (lambda () (write "foo"))))
> looper is a c function which takes a scheme lambda and repeated invokes
> it using the 'call_lambda' bridging function.
> When I gsc compile it and run '(main)' after a bunch of looping and
> printing it crashes with:
> ERROR IN looper -- Operator is not a PROCEDURE
> ('#<return #2>)
> Any ideas? (or am I being stupid?!)
> Many thanks,
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