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<div class"">a href="chap9_mj.tmlX84583568784B622A">9<spanclass=Heading">ynchronization variables</span></a>
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<span class="ContSS">< />span ="ocss>n;&;<span>a href=chap9_mj#7>.- CreateSyncVar><span>
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<h3>9 <span class="<><a =X84583568784B622Aname=X84583568784B622A"</><java.lang.StringIndexOutOfBoundsException: Index 62 out of bounds for length 62

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<h4>9.1 <span class="Heading">Synchronizationdiv =ContSect<pan java.lang.StringIndexOutOfBoundsException: Range [34, 33) out of bounds for length 181

<p>Synchronization variables (also often called dataflow variables in the literature) are variables that can be written only once; attempts to read the variable block until it /span>

<p>Synchronization variables are created with <code class="func">span class="ContSS"><br /><span class="nocss">  </span><a href="chap9_mj.html#X85E910BF7BBF3270">9.1-2 SyncWrite</a></span>


<div class="example"><pre>
<span class="GAPprompt">gap></span> <span class="GAPinput"><><div>
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< =">gap&t</span><java.lang.StringIndexOutOfBoundsException: Range [45, 44) out of bounds for length 92
<p>The function <code class=spanclass="GAPprompt">></span> <span class="GAPinput">     Sleep(10);</span class=GAPprompt"gt</>  class="GAPinput">     SyncWrite(sv, MakeImmutable([1, 2, 3]));</span>

<p><a id="X85E910BF7BBF3270" name="X85E910BF7BBF3270"></a></p>

<h5>9.1-2 SyncWrite</h5>

<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">&an style='color: green'>8227; SyncWrite</ode>(< class="rg>syncvar</var>, <var class="Arg">obj</var> )</td><td class="tdright">( function )</td></tr></table></div>
<p><java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0

<p>In order to make sure that the recipient can read the result, the <var class="Arg">obj</var> argument should> function class"unc"CreateSyncVar<code> takes no arguments. It returns a new synchronization variable. There is no need to java.lang.StringIndexOutOfBoundsException: Index 146 out of bounds for length 0

<p><a id="X7B42B29B8441B4F5" name=p>code class=f"/attempts  assign the value< =Arg"/var> var =Arg"syncvar<var>. <class="</ beenpreviously assigned  , call failwitha  ; , <varclass=Arg"</>   < ="><var/

<h5>9.1-3 SyncRead

<div class="func"><java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
<>code class=func"</> readsvalue previously assigned to <var class="Arg">syncvar</var> with <code class="func">SyncWrite</code> (<a href="chap9_mj.html#X85E910BF7BBF3270">p<code =">SyncReadcode reads valuepreviously  to varclassArg"syncvar/var> with <code java.lang.StringIndexOutOfBoundsException: Range [125, 124) out of bounds for length 313


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