Which version of Racket are you using? I think Ryan pushed some custodian related improvements to the db library recently.
Robby On Friday, December 26, 2014, Dmitry Pavlov <[email protected]> wrote: > Hello, > > Let us say I put this program into DrRacket's Definitions window: > > ----------------------------------------------------------------- > #lang racket > (require db) > > (define path "aaa.db") > > (when (file-exists? path) > (delete-directory/files path)) > > (define conn (sqlite3-connect #:database path #:mode 'create)) > ----------------------------------------------------------------- > > and then press the "Run" button. After that, I play with conn > in the Interactions window. When I have played enough, > I press the "Run" button again. Here is what I get: > > delete-file: cannot delete file > path: [...]\aaa.db > system error: Permission denied; errno=13 > > The reason is that I forgot to (disconnect conn) in the end. > (I get that only on Windows; Linux is OK with removing opened files). > > How do I disconnect automatically? Putting the (disconnect conn) > into the Definitions window is not a solution, as I want to use > conn in the Interactions (also I want to be safe against the > "Stop" button pressed in the middle of the program before the > disconnect happens) > > I tried to use a will executor: > > ----------------------------------------------------------------- > (define an-executor (make-will-executor)) > (void > (thread > (lambda () > (let loop () > (will-execute an-executor) > (loop))))) > > (define (executor-proc v) (printf "I am now garbage\n") (disconnect v)) > (will-register an-executor conn executor-proc) > ----------------------------------------------------------------- > > Surprisingly, it did not work for the database connection (while it > does work for other kinds of objects), and I have no idea why. It > does not work even with I call the GC explicitly: > > ----------------------------------------------------------------- > (set! conn #f) > (collect-garbage) > ----------------------------------------------------------------- > > Is it possible to make the will executor work? > Generally speaking, what is the recommended way to do this kind > of thing? > > > Best regards, > > Dmitry > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users >
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