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POIs delete p where p is a pointer to array always a memory leak?
 

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  1. POIs delete p where p is a pointer to array always a memory leak?
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    <p>following a discussion in a software meeting I've set out to find out if deleting a dynamically allocated, primitives array with plain <code>delete</code> will cause a memory leak. </p> <p>I have written this tiny program and compiled it with visual studio 2008 running on windows XP:</p> <pre><code>#include "stdafx.h" #include "Windows.h" const unsigned long BLOCK_SIZE = 1024*100000; int _tmain() { for (unsigned int i =0; i &lt; 1024*1000; i++) { int* p = new int[1024*100000]; for (int j =0;j&lt;BLOCK_SIZE;j++) p[j]= j % 2; Sleep(1000); delete p; } } </code></pre> <p>I than monitored the memory consumption of my application using task manager, surprisingly the memory was allocated and freed correctly, allocated memory did not steadily increase as was expected </p> <p>I've modified my test program to allocate a non primitive type array :</p> <pre><code>#include "stdafx.h" #include "Windows.h" struct aStruct { aStruct() : i(1), j(0) {} int i; char j; } NonePrimitive; const unsigned long BLOCK_SIZE = 1024*100000; int _tmain() { for (unsigned int i =0; i &lt; 1024*100000; i++) { aStruct* p = new aStruct[1024*100000]; Sleep(1000); delete p; } } </code></pre> <p>after running for for 10 minutes there was no meaningful increase in memory </p> <p>I compiled the project with warning level 4 and got no warnings.</p> <p>is it possible that the visual studio run time keep track of the allocated objects types so there is no different between <code>delete</code> and <code>delete[]</code> in that environment ? </p>
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    1. CODuplicate? http://stackoverflow.com/questions/1913343/how-could-pairing-new-with-delete-possibly-lead-to-memory-leak-only
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      1. USPhilip Potter
    2. CO@Philip Potter: Not of that very question - that one is specifically about causing a memory leak. And memory leak is not typical in this case.
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    3. COTry it with an array of `shared_ptr<int>`, each pointing to a different allocated int, and you'll see whether your implementation is making `delete` and `delete[]` equivalent. Always this fascination in C++ with things that people know are wrong, are clearly stated in the standard to be wrong, and yet which appear as if they might sometimes just happen to work ;-)
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