On 2008 Feb 25, at 00:19, Daishi Kato wrote:
Hi,
SRFI-18 states,
The mutex primitives specified in this SRFI do not implement
"recursive" mutex semantics; an attempt to lock a mutex that is
locked implies that the current thread must wait even if the mutex
is owned by the current thread
so, I want a macro or procedure to support "recursive" mutex.
Would be glad someone can note on it.
Here's my macro, not sure if it works:
Isn't there a similar code?
(define my-mutex (make-mutex))
(define-macro (my-lock . body)
`(let ([result #f])
(if (eq? (mutex-state my-mutex) (current-thread))
(set! result (begin ,@body))
;;else
(begin
(mutex-lock! my-mutex)
(set! result (begin ,@body))
(mutex-unlock! my-mutex)))
result))
I have actually never used the Chicken threading capabilities, but
with almost
any mutex code it's a safe bet that there's race condition. In this
case, is
it possible that the mutex could become locked between a false eq?
result and
the call of mutex-lock! ?
I think recursive mutex locking almost always needs a conditional lock
operation.
-- v
_______________________________________________
Chicken-users mailing list
[email protected]
http://lists.nongnu.org/mailman/listinfo/chicken-users
