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primarykey
Id
3305917
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0
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0
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2
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CreationDate
2010-07-22T05:07:36.643
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0
LastActivityDate
2010-07-22T05:26:14.820
LastEditDate
2017-05-23T12:34:04.237
LastEditorUserId
-1
OwnerUserId
87234
ParentId
3305876
PostTypeId
2
Score
12
ViewCount
0
LastEditorDisplayName
text
Body
This answer is based off <a href="https://stackoverflow.com/questions/75538/hidden-features-of-c/2176229#2176229">this fun-fact</a>: In a function returning <code>void</code>, you can return any expression of which the type is void. So the simple solution is: <pre><code>virtual T Execute() const { if (comm) // boolean logic change, typo in OP? return comm(); else return static_cast<T>(NULL); } </code></pre> When <code>T = void</code>, the last return statement is equivalent to <code>return;</code>. <hr> However, I feel this is bad design. Is <code>NULL</code> meaningful for every <code>T</code>? I don't think so. I would throw an exception: <pre><code>virtual T Execute() const { if (comm) return comm(); else throw std::runtime_error("No function!") } </code></pre> However, this is done <a href="http://www.boost.org/doc/libs/1_43_0/doc/html/boost/bad_function_call.html" rel="nofollow noreferrer">automatically by Boost</a>, so your code becomes the much cleaner: <pre><code>virtual T Execute() const { return comm(); } </code></pre> You could then add additional functionality, such as: <pre><code>bool empty(void) const { return !comm; // or return comm.empty() if you're the explicit type } </code></pre> So the user can check if it can be called prior to calling it. Of course at this point, unless your class has additional functionality you've left out for the sake of the question, I see no reason not to just use <code>boost::function</code> in the first place.
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1. POUsing template for return value. how to handle void return?
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1. USGManNickG
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1. POUsing template for return value. how to handle void return?
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1. COis that C-style cast I am seeing there?
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2. CO@akira: Gone. :) Just a temporary before I touched it up a bit.
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