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    <blockquote> <p>Can I use shared_ptr with malloc and free.</p> </blockquote> <p>Yes.</p> <blockquote> <p>Can anyone point out me sample code base.</p> </blockquote> <p>You need to provide a custom deleter, so that memory is released using <code>free</code> rather than the default <code>delete</code>. This can be a pointer to the <code>free</code> function itself:</p> <pre><code>shared_ptr&lt;void&gt; memory(malloc(1024), free); </code></pre> <p>Remember that <code>malloc</code> and <code>free</code> only deal with raw memory, and you're responsible for correctly creating and destroying any non-trivial objects you might want to keep in that memory.</p> <blockquote> <p>if I create shared_ptr in my application and pass this pointer to another function if they are using malloc or calloc. will it impact any functionality.</p> </blockquote> <p>I don't quite follow the question. You can use this <code>shared_ptr</code> interchangably with "normal" shared pointers, if that's what you're asking. <em>Type erasure</em> ensures that users of the pointers aren't affected by different types of deleter. As with any shared pointer, you have to be a bit careful if you extract the raw pointer with <code>get()</code>; specifically, don't do anything that might <code>free</code> it, since you've irrevocably assigned ownership to the shared pointer.</p> <blockquote> <p>We have call some function which accept double pointer and fill the structure inside their application and use malloc Can we assign those pointer to shared_ptr.</p> </blockquote> <p>I guess you mean something like:</p> <pre><code>double * make_stuff() { double * stuff = static_cast&lt;double*&gt;(malloc(whatever)); put_stuff_in(stuff); return stuff; } shared_ptr&lt;double&gt; shared_stuff(make_stuff(), free); </code></pre> <p>UPDATE: I didn't spot the phrase "double pointer", by which I assume you mean the C-style use of a pointer to emulate a reference to emulate a return value; you can do that too:</p> <pre><code>void make_stuff(double ** stuff); double * stuff = 0; make_stuff(&amp;stuff); shared_ptr&lt;double&gt; shared_stuff(stuff, free); </code></pre> <blockquote> <p>How will handle with realloc and calloc</p> </blockquote> <p>It's fine to initialise the shared pointer with the result of <code>calloc</code>, or anything else that returns memory to be released using <code>free</code>. You can't use <code>realloc</code>, since <code>shared_ptr</code> has taken ownership of the original pointer and won't release it without calling <code>free</code>.</p>
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    1. USMike Seymour
    1. USMike Seymour
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    1. COI think "double pointer" might mean `void allocate(int** p)` which would assign `*p` to new memory. This would be hard to make work with shared pointer I think.
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      1. USRasmus Storjohann
    2. CO@RasmusStorjohann: That's no harder than with any other way of acquiring the pointer. I've updated the answer, in case that was what was meant.
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