title: shared_ptr : "call of an object of a class type without appropriate operator() or conversion function to pointer-to-function type"
body: <pre><code>#include "boost\shared_ptr.hpp"
  
  class A{
  
  public:
  A(){}
  ~A(){}
  
  };
  
  int main()
  {
      boost::shared_ptr&lt;A&gt; ptrA;
      ptrA(new A); 
  
  }
  </code></pre>
  
  <p>I would like to know why this code won't compile? I want to know the difference if I just use </p>
  
  <pre><code>boost::shared_ptr&lt;A&gt; ptrA(new A);?
  </code></pre>