CComGITPtr Class

This class provides methods for dealing with interface pointers and the global interface table (GIT).

Syntax

template <class T>
class CComGITPtr

Parameters

T
The type of the interface pointer to be stored in the GIT.

Members

Public Constructors

Name Description
CComGITPtr::CComGITPtr The constructor.
CComGITPtr::~CComGITPtr The destructor.

Public Methods

Name Description
CComGITPtr::Attach Call this method to register the interface pointer in the global interface table (GIT).
CComGITPtr::CopyTo Call this method to copy the interface from the global interface table (GIT) to the passed pointer.
CComGITPtr::Detach Call this method to disassociate the interface from the CComGITPtr object.
CComGITPtr::GetCookie Call this method to return the cookie from the CComGITPtr object.
CComGITPtr::Revoke Call this method to remove the interface from the global interface table (GIT).

Public Operators

Name Description
CComGITPtr::operator DWORD Returns the cookie from the CComGITPtr object.
CComGITPtr::operator = Assignment operator.

Public Data Members

Name Description
CComGITPtr::m_dwCookie The cookie.

Remarks

Objects that aggregate the free threaded marshaler and need to use interface pointers obtained from other objects must take extra steps to ensure that the interfaces are correctly marshaled. Typically this involves storing the interface pointers in the GIT and getting the pointer from the GIT each time it is used. The class CComGITPtr is provided to help you use interface pointers stored in the GIT.

Note

The global interface table facility is only available on Windows 95 with DCOM version 1.1 and later, Windows 98, Windows NT 4.0 with Service Pack 3 and later, and Windows 2000.

Requirements

Header: atlbase.h

CComGITPtr::Attach

Call this method to register the interface pointer in the global interface table (GIT).

HRESULT Attach(T* p) throw();

HRESULT Attach(DWORD dwCookie) throw();

Parameters

p
The interface pointer to be added to the GIT.

dwCookie
The cookie used to identify the interface pointer.

Return Value

Returns S_OK on success, or an error HRESULT on failure.

Remarks

In debug builds, an assertion error will occur if the GIT is not valid, or if the cookie is equal to NULL.

CComGITPtr::CComGITPtr

The constructor.

CComGITPtr() throw();
CComGITPtr(T* p);
CComGITPtr(const CComGITPtr& git);
explicit CComGITPtr(DWORD dwCookie) throw();
CComGITPtr(CComGITPtr&& rv);

Parameters

p
[in] An interface pointer to be stored in the global interface table (GIT).

git
[in] A reference to an existing CComGITPtr object.

dwCookie
[in] A cookie used to identify the interface pointer.

rv
[in] The source CComGITPtr object to move data from.

Remarks

Creates a new CComGITPtr object, optionally using an existing CComGITPtr object.

The constructor utilizing rv is a move constructor. The data is moved from the source, rv, and then rv is cleared.

CComGITPtr::~CComGITPtr

The destructor.

~CComGITPtr() throw();

Remarks

Removes the interface from the global interface table (GIT), using CComGITPtr::Revoke.

CComGITPtr::CopyTo

Call this method to copy the interface from the global interface table (GIT) to the passed pointer.

HRESULT CopyTo(T** pp) const throw();

Parameters

pp
The pointer which is to receive the interface.

Return Value

Returns S_OK on success, or an error HRESULT on failure.

Remarks

The interface from the GIT is copied to the passed pointer. The pointer must be released by the caller when it is no longer required.

CComGITPtr::Detach

Call this method to disassociate the interface from the CComGITPtr object.

DWORD Detach() throw();

Return Value

Returns the cookie from the CComGITPtr object.

Remarks

It is up to the caller to remove the interface from the GIT, using CComGITPtr::Revoke.

CComGITPtr::GetCookie

Call this method to return the cookie from the CComGITPtr object.

DWORD GetCookie() const;

Return Value

Returns the cookie.

Remarks

The cookie is a variable used to identify an interface and its location.

CComGITPtr::m_dwCookie

The cookie.

DWORD m_dwCookie;

Remarks

The cookie is a member variable used to identify an interface and its location.

CComGITPtr::operator =

The assignment operator.

CComGITPtr& operator= (T* p);
CComGITPtr& operator= (const CComGITPtr& git);
CComGITPtr& operator= (DWORD dwCookie);
CComGITPtr& operator= (CComGITPtr&& rv);

Parameters

p
[in] A pointer to an interface.

git
[in] A reference to a CComGITPtr object.

dwCookie
[in] A cookie used to identify the interface pointer.

rv
[in] The CComGITPtr to move data from.

Return Value

Returns the updated CComGITPtr object.

Remarks

Assigns a new value to a CComGITPtr object, either from an existing object or from a reference to a global interface table.

CComGITPtr::operator DWORD

Returns the cookie associated with the CComGITPtr object.

operator DWORD() const;

Remarks

The cookie is a variable used to identify an interface and its location.

CComGITPtr::Revoke

Call this method to remove the current interface from the global interface table (GIT).

HRESULT Revoke() throw();

Return Value

Returns S_OK on success, or an error HRESULT on failure.

Remarks

Removes the interface from the GIT.

See Also

Free Threaded Marshaler
Accessing Interfaces Across Apartments
When to Use the Global Interface Table
Class Overview