Destructs a com::ptr.



On destruction, the com::ptr releases all references it owns to its COM object. Assuming that there are no other references held to the COM object, the COM object will be deleted and its memory freed.


This example implements a CLR class that uses a com::ptr to wrap its private member IXMLDOMDocument object. In the main function, the two XmlDocument objects' destructors will be called when they go out of the scope of the try block, resulting in the underlying com::ptr destructor being called, releasing all owned references to the COM object.

// comptr_dtor.cpp
// compile with: /clr /link msxml2.lib
#include <msxml2.h>
#include <msclr\com\ptr.h>

#import <msxml3.dll> raw_interfaces_only

using namespace System;
using namespace System::Runtime::InteropServices;
using namespace msclr;

// a ref class that uses a com::ptr to contain an 
// IXMLDOMDocument object
ref class XmlDocument {
   // construct the internal com::ptr with a null interface
   // and use CreateInstance to fill it
   XmlDocument(String^ progid) {

   // construct the internal com::ptr with a COM object
   XmlDocument(IXMLDOMDocument* pDoc) : m_ptrDoc(pDoc) {}

   // note that the destructor will call the com::ptr destructor
   // and automatically release the reference to the COM object

   com::ptr<IXMLDOMDocument> m_ptrDoc;

// use the ref class to handle an XML DOM Document object
int main() {
   IXMLDOMDocument* pDoc = NULL;

   try {
      // create an XML DOM document object
      Marshal::ThrowExceptionForHR(CoCreateInstance(CLSID_DOMDocument30, NULL, 
         CLSCTX_ALL, IID_IXMLDOMDocument, (void**)&pDoc));
      // construct the ref class with the COM object
      XmlDocument doc1(pDoc);

      // or create the class from a progid string
      XmlDocument doc2("Msxml2.DOMDocument.3.0");
   // doc1 and doc2 destructors are called when they go out of scope
   // and the internal com::ptr releases its reference to the COM object
   catch (Exception^ e) {
   finally {
      if (NULL != pDoc) {


Header file <msclr\com\ptr.h>

Namespace msclr::com

See Also




Other Resources

ptr Members