Re: [Chicken-users] Threads and dynamic-wind still problematic

[Tobia Conforto]

Peter Bex wrote:
> Yup, thanks for asking him.  It still sucks, though ;)

This is yet another solution, in case you can't (or don't want to)  
steal the exception handler from the primordial thread.  This one may  
be safer.  But then again, I'm probably missing Marc Feeley's point  
completely, so it might not be safe to use at all :-)

#;1> (use srfi-18)
; loading library srfi-18 ...
#;2> (define (exception-protect thunk)
--->   (define exn-message (condition-property-accessor 'exn 'message))
--->   (lambda ()
--->     (call-with-current-continuation
--->       (lambda (quit)
--->         (with-exception-handler
--->           (lambda (exn)
--->             (print "Error: " (exn-message exn))
--->             (quit))
--->           thunk)))))
#;3> (define (test)
--->   (dynamic-wind
--->     (lambda ()
--->       (print "BEFORE"))
--->     (lambda ()
--->       (error "die!")
--->       (print "OH NOES"))
--->     (lambda ()
--->       (print "AFTER"))))
#;4> (thread-join! (thread-start! (exception-protect test)))
BEFORE
Error: die!
AFTER
#;5>

Tobia