ptr::~ptr
Destructs a com::ptr.
~ptr();
Remarks
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.
Example
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 {
public:
// construct the internal com::ptr with a null interface
// and use CreateInstance to fill it
XmlDocument(String^ progid) {
m_ptrDoc.CreateInstance(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
private:
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) {
Console::WriteLine(e);
}
finally {
if (NULL != pDoc) {
pDoc->Release();
}
}
}
Requirements
Header file <msclr\com\ptr.h>
Namespace msclr::com