Re: [Chicken-users] are standard bindings write protected?

[felix]

On 22 Nov 2003 16:49:43 +0100, Joerg F. Wittenberger 
<address@hidden> wrote:

> Hi Felix,
>
> It appears to be actually worse than just that.  The code, compiled in
> module A modifies the globals, code in the module B (depending on A),
> uses it, but gets the original definition instead my modified one.
>
> I also see some suspicious messages relating to other definitions I
> wrote over.  Like here:
>
> Warning: global variable `abort' is never used
> Warning: global variable `signal' is never used
> Warning: global variable `##sys#error' is never used

You are probably compiling in block-mode, or using
the `export' declaration, without exporting the variables mentioned
above.

> `force' is not among them, but it's also used within A, which should
> be reason enpugh.
>
> The interpreter in contrast uses the modified force, but then goes
> into an endless loop within 'UnlockedWait below.  This seems a srfi-18
> problem, isn't it?
>
>
> ;;** future
>
> (define-record-type <future>
> (internal-make-future mutex condition has-result result)
> future?
> (mutex future-mutex)
> (condition future-condition)
> (has-result future-has-result future-has-result-set!)
> (result future-result future-result-set!))
>
>
>
> (define (logerr . args)
> (apply format (current-error-port) args)
> (flush-output (current-error-port)))
>
> (define (debug lbl x) (logerr " D ~a: ~s\n" lbl x) x)
>
> (define (future-force f)
> (if (debug 'HasResult (future-has-result f))
> (future-result f)
> (begin
> (debug 'GotLock (mutex-lock! (future-mutex f)))
> (if (debug 'HasNow (future-has-result f))
> (begin
> (debug 'Unlocked (mutex-unlock! (future-mutex f)))
> (future-result f))
> (begin
> (debug 'UnlockedWait (mutex-unlock! (future-mutex f) (future-condition f)) 
>
>
> )
> (future-result f))))))
>
> (define (make-future thunk name)
> (let ((f (internal-make-future (make-mutex)
> (make-condition-variable)
> #f 'invalid)))
> (thread-start!
> (make-thread
> (lambda ()
> (future-result-set! f (with-exception-guard identity thunk))
                                       ^^^^^
                                       handler

(the error doesn't get shown, the thread terminates, but since
there is no join, the exception doesn't get signalled.


cheers,
felix