<div dir="ltr"><div><div><div><div>Hello Yann,<br><br></div>Indeed, you are correct. New() will return a smart pointer, but other methods will return a pointer, so you cannot use the keyword "auto" with these other methods.<br></div>The two following links give some insight in why ITK is implemented this way:<br><a href="https://itk.org/Wiki/ITK/Examples/Utilities/ReturnObjectFromFunction">https://itk.org/Wiki/ITK/Examples/Utilities/ReturnObjectFromFunction</a><br><a href="https://itk.org/pipermail/insight-developers/2011-April/018011.html">https://itk.org/pipermail/insight-developers/2011-April/018011.html</a><br><br></div>Hope this helps,<br></div>Francois<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Mar 21, 2017 at 6:45 AM, asertyuio via Insight-users <span dir="ltr"><<a href="mailto:insight-users@itk.org" target="_blank">insight-users@itk.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p style="margin:0px 0px 1.2em!important">Hi Hans,</p>
<p style="margin:0px 0px 1.2em!important">Thanks for your
answer !</p>
<p style="margin:0px 0px 1.2em!important">I was asking that
because when I use auto keyword with a filter output, it seems
like is result in a normal point type, not a smart pointer, so a
code with</p>
<pre style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;font-size:1em;line-height:1.2em;margin:1.2em 0px"><code style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(234,234,234);background-color:rgb(248,248,248);border-radius:3px;display:inline;white-space:pre-wrap;overflow:auto;border-radius:3px;border:1px solid rgb(204,204,204);padding:0.5em 0.7em;display:block!important">auto testOutput = testFilter->GetOutput();
</code></pre>
<p style="margin:0px 0px 1.2em!important">has not the same
behavior as</p>
<pre style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;font-size:1em;line-height:1.2em;margin:1.2em 0px"><code style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(234,234,234);background-color:rgb(248,248,248);border-radius:3px;display:inline;white-space:pre-wrap;overflow:auto;border-radius:3px;border:1px solid rgb(204,204,204);padding:0.5em 0.7em;display:block!important"> FilterOutputType::Pointer testOutput = testFilter->GetOutput();
</code></pre>
<p style="margin:0px 0px 1.2em!important"><code style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(234,234,234);background-color:rgb(248,248,248);border-radius:3px;display:inline">testOutput</code>
is a smart pointer in the second case, and a normal pointer in
the first one.</p>
<p style="margin:0px 0px 1.2em!important">I was wondering if
it could interfere with the smart pointer role (for example
causing memory leak, or wrong reference count).</p>
<p style="margin:0px 0px 1.2em!important">After a deeper look,
<code style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(234,234,234);background-color:rgb(248,248,248);border-radius:3px;display:inline">New()</code>
return a smart pointer (so with auto =, no problem) and <code style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(234,234,234);background-color:rgb(248,248,248);border-radius:3px;display:inline">GetOutput()</code>
a pointer. So the second code snipset just creates another
instance of a smart pointer.</p>
<p style="margin:0px 0px 1.2em!important">I hope what was my
question is now clearer !<br>
Yann</p><span class="">
<p style="margin:0px 0px 1.2em!important">Le 21/03/2017 à
01:43, Johnson, Hans J a écrit :</p>
<p style="margin:0px 0px 1.2em!important"></p>
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<p></p>
<blockquote type="cite">
<pre>Yann,
It will work only if you are compiling with C++11, and you have no intention of sharing your code with others who may not use C++11 syntax.
ITK proper currently maintains backwards compatibility with older versions of C++.
Hans
</pre>
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