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    <p>I notice that in test-define.rkt you have this line</p> <pre><code>(set! test3 (add1 test)) </code></pre> <p>Should <code>test3</code> be <code>test</code> ?</p> <p>This might explain why you saw that two zeros (test never changed).</p> <p>EDIT 2</p> <p>For convenience I put your two modules in the same file and changed the contract of test:</p> <pre><code>#lang racket (module test-define racket (provide test) ; (provide (contract-out [test integer?])) (provide get-test) (provide (contract-out [add-test! (-&gt; void)])) (define test 0) (define (add-test!) (set! test (add1 test))) (define (get-test) test)) (module ack racket (require (submod ".." test-define)) (printf "~a~%" test) (add-test!) (printf "~a~%" test)) (require (submod "." ack)) </code></pre> <p>Now I see the 0 1 vs 0 0 output as you do.</p> <p>Hmmm. Why?</p> <p>Well. If we change the provide forms to use no contracts at all, the output is 0 1.</p> <p>Adding a contract shouldn't change this behaviour (I think). Maybe a bug?</p> <p><a href="http://pre.racket-lang.org/docs/html/guide/contracts-gotchas.html?q=contract&amp;q=ignore" rel="nofollow">http://pre.racket-lang.org/docs/html/guide/contracts-gotchas.html?q=contract&amp;q=ignore</a></p> <p>Says:</p> <blockquote> <p>The contract library assumes that variables exported via contract-out are not assigned to, but does not enforce it. Accordingly, if you try to set! those variables, you may be surprised. ...snip... Moral: This is a bug that we will address in a future release.</p> </blockquote>
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    1. COthank you for your answer, this is my first stackoverflow answer!But this is my type mistake, I fix it already.This problem confuse me, is some basic theory of racket's module or contract i don't gasp?
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    2. COI can not run your ack.rkt as it is above. A definition of `get-test` is missing.
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    3. COI'm very sorry, I mistype again. it should be:(printf "~a~%" test) and my racket version is 5.2.1. Thanks for your respones, I expected your answer.
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