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<div>Interesting use for select_replace, I think I see. If Old changes in the meantime, it wont succeed as Old wont be found.<br><br>I am aware of select_replace, did not realise you could use it this way. Nifty!</div><div><br></div>
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On Tuesday, November 20, 2018, 9:16:04 a.m. EST, Sverker Eriksson <sverker@erlang.org> wrote:
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<div><div id="yiv5018880429"><div><div><p>You can use ets:select_replace/2 to do an atomic compare-and-swap operation:</p><p><br clear="none"></p>
<div class="yiv5018880429example yiv5018880429hljs"><pre>[Old] = ets:lookup(T, Key),</pre><pre>New = update_object(Old),</pre><pre>Success = (1 =:= ets:select_replace(T, [{Old, [], [{const, New}]}])),
<br clear="none"></pre><pre><br clear="none"></pre><pre>ets:select_replace/2 was introduced in OTP-20.</pre><pre><br clear="none"></pre><pre><br clear="none"></pre><pre>/Sverker</pre><pre> </pre></div></div><div><br clear="none"></div><div class="yiv5018880429yqt4280287477" id="yiv5018880429yqt14614"><div>On mån, 2018-11-19 at 18:44 +0000, Vans S wrote:</div><blockquote type="cite"><div>Currently there is no atomic function to update a ETS value when its not a tuple. For example if one of my ETS values is a map, and I want to put an element into the map, I have no atomic way to do so.<br clear="none"><br clear="none">Is there anyone else that really has a need for a function like :ets.update/3 where arg 1 is ets_table, 2 is key, 3 is fun callback that is called passing the original element and the reply should be the new element?</div><div class="yiv5018880429ydp4921ffaeyahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"></div><pre>_______________________________________________
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