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_com_ptr_t

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Microsoft Specific

A _com_ptr_t object encapsulates a COM interface pointer and is called a “smart” pointer. This template class manages resource allocation and deallocation, via function calls to the IUnknown member functions: QueryInterface, AddRef, and Release.

A smart pointer is usually referenced by the typedef definition provided by the _COM_SMARTPTR_TYPEDEF macro. This macro takes an interface name and the IID, and declares a specialization of _com_ptr_t with the name of the interface plus a suffix of Ptr. For example,

_COM_SMARTPTR_TYPEDEF(IMyInterface, __uuidof(IMyInterface));

declares the _com_ptr_t specialization IMyInterfacePtr.

A set of function templates, not members of this template class, support comparisons with a smart pointer on the right-hand side of the comparison operator.

#include <comdef.h>

Compiler COM Support Class Overview

Construction

_com_ptr_t Constructs a _com_ptr_t object.

Low-level Operations

AddRef Calls the AddRef member function of IUnknown on the encapsulated interface pointer.
Attach Encapsulates a raw interface pointer of this smart pointer’s type.
CreateInstance Creates a new instance of an object given a CLSID or ProgID.
Detach Extracts and returns the encapsulated interface pointer.
GetActiveObject Attaches to an existing instance of an object given a CLSID or ProgID.
GetInterfacePtr Returns the encapsulated interface pointer.
QueryInterface Calls the QueryInterface member function of IUnknown on the encapsulated interface pointer.
Release Calls the Release member function of IUnknown on the encapsulated interface pointer.

Operators

operator = Assigns a new value to an existing _com_ptr_t object.
operators ==, !=, <, >, <=, >= Compare the smart pointer object to another smart pointer, raw interface pointer, or NULL.
Extractors Extract the encapsulated COM interface pointer.

END Microsoft Specific