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POIssues with C++ 'new' operator?
 

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  1. POIssues with C++ 'new' operator?
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    <p>I've recently come across <a href="http://www.scs.stanford.edu/~dm/home/papers/c++-new.html" rel="nofollow noreferrer">this rant</a>.</p> <p>I don't quite understand a few of the points mentioned in the article:</p> <ul> <li>The author mentions the small annoyance of <code>delete</code> vs <code>delete[]</code>, but seems to argue that it is actually necessary (for the compiler), without ever offering a solution. Did I miss something?</li> <li><p>In the section 'Specialized allocators', in function <code>f()</code>, it seems the problems can be solved with replacing the allocations with: (omitting alignment)</p> <pre><code>// if you're going to the trouble to implement an entire Arena for memory, // making an arena_ptr won't be much work. basically the same as an auto_ptr, // except that it knows which arena to deallocate from when destructed. arena_ptr&lt;char&gt; string(a); string.allocate(80); // or: arena_ptr&lt;char&gt; string; string.allocate(a, 80); arena_ptr&lt;int&gt; intp(a); intp.allocate(); // or: arena_ptr&lt;int&gt; intp; intp.allocate(a); arena_ptr&lt;foo&gt; fp(a); fp.allocate(); // or: arena_ptr&lt;foo&gt;; fp.allocate(a); // use templates in 'arena.allocate(...)' to determine that foo has // a constructor which needs to be called. do something similar // for destructors in '~arena_ptr()'. </code></pre></li> <li><p>In 'Dangers of overloading ::operator new[]', the author tries to do a <code>new(p) obj[10]</code>. Why not this instead (far less ambiguous):</p> <pre><code>obj *p = (obj *)special_malloc(sizeof(obj[10])); for(int i = 0; i &lt; 10; ++i, ++p) new(p) obj; </code></pre></li> <li><p>'Debugging memory allocation in C++'. Can't argue here.</p></li> </ul> <p>The entire article seems to revolve around classes with <em>significant</em> <em>constructors</em> and <em>destructors</em> located in a <em>custom memory management scheme</em>. While that could be useful, and I can't argue with it, it's pretty limited in commonality.</p> <p>Basically, we have placement new and per-class allocators -- what problems can't be solved with these approaches?</p> <p>Also, in case I'm just thick-skulled and crazy, in <strong>your</strong> ideal C++, what would replace <code>operator new</code>? Invent syntax as necessary -- what would be <strong>ideal</strong>, simply to help me understand these problems better.</p>
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