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POCallling object constructor/destructor with a custom allocator
 

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    <p>I have been looking into custom allocators and I quite often see them using some kind of function to allocate memory. For testing purposes and further educate my self, I tried to make a "simple" example of doing so. However, there is one fundamental thing I am understand on how to do. One of the key differences in <code>malloc</code> vs <code>new</code> is that with new the constructor is called. What if I wanted to write my own allocator that was essentially replacing <code>new</code>, how would I get the constructor to be called when using <code>malloc</code>?</p> <p>I understand that on classes I can overload <code>new</code> and <code>delete</code> for the class, so I suppose a big part of the question is, how is <code>new</code> calling the objects constructor during allocation? Similarly, I am interested in how <code>delete</code> is calling the destructor. </p> <p>I created a sample test code that I was hoping to have the <code>SomeClass</code> constructor called during allocation, but I don't see how.</p> <pre><code>#include &lt;malloc.h&gt; void* SomeAllocationFunction(size_t size) { return malloc(size); } class SomeClass { public: SomeClass() { int con = 1000; } ~SomeClass() { int des = 80; } }; int main(void){ SomeClass* t = (SomeClass*)SomeAllocationFunction(sizeof(SomeClass)); return 0; } </code></pre> <p>(As a note, I know I can just use <code>new</code>. However, for the purposes of learning I am trying to create a custom allocator that does not just call <code>new</code> or <code>placement new</code>).</p>
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