IExternalConnection::AddConnection

Increments an object's count of its strong external connections (links).

HRESULT AddConnection(

DWORD exconn,	//Type of external connection
DWORD dwreserved	//Used by OLE to pass connection information
);

Parameters
exconn

[out] Specifies the type of external connection to the object. The only type of external connection currently supported by this interface is strong, which means that the object must remain alive as long as this external connection exists. Strong external connections are represented by the value EXTCONN_STRONG = 0x0001, which is defined in the enumeration EXTCONN.

dwreserved
Passes information about the connection. This parameter is reserved for use by OLE. Its value can be zero, but not necessarily. Therefore, implementations of AddConnection should not contain blocks of code whose execution depends on whether a zero value is returned.

Return Value
DWORD value

The number of reference counts on the object; used for debugging purposes only.

Comments
An object created by a EXE object application relies on its stub manager to call IExternalConnection::AddConnection whenever a link client activates and therefore creates an external lock on the object. When the link client breaks the connection, the stub manager calls IExternalConnection::ReleaseConnection to release the lock.

Since DLL object applications exist in the same process space as their objects, they do not utilize RPC (remote procedure calls) and therefore do not have stub managers to keep track of external connections. Therefore, DLL object applications that support external links to their objects must implement IExternalConnection so link clients can directly call the interface to inform them when connections are added or released.

The following is a typical implementation for the AddConnection method:

DWORD XX::AddConnection(DWORD extconn, DWORD dwReserved)
{
return extconn&EXTCONN_STRONG ? ++m_cStrong : 0;
}

See Also
IExternalConnection::ReleaseConnection, IRunnableObject::LockRunning, OleLockRunning

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