This function makes a private copy of the specified proxy.
CoCopyProxy makes a private copy of the specified proxy. Typically, this function is called when a client needs to change the authentication information of its proxy through a call to either CoSetProxyBlanket or IClientSecurity::SetBlanket without changing this information for other clients.
CoSetProxyBlanket affects all the users of an instance of a proxy, so creating a private copy of the proxy through a call to CoCopyProxy and then calling CoSetProxyBlanket (or IClientSecurity::SetBlanket) using the copy eliminates the problem.
This helper function encapsulates the following sequence of common calls (error handling excluded).
pProxy->QueryInterface(IID_IClientSecurity, (void**)&pcs); pcs->CopyProxy(punkProxy, ppunkCopy); pcs->Release();
Local interfaces may not be copied. IUnknown and IClientSecurity are examples of existing local interfaces.
Copies of the same proxy have a special relationship with respect to QueryInterface. Given a proxy, a, of the IA interface of a remote object, suppose a copy of a is created, called b.
In this case, calling QueryInterface from the b proxy for IID_IA will not retrieve the IA interface on b, but the one on a, the original proxy with the default security settings for the IA interface.
To determine whether the platform supports this function, see Determining Supported COM APIs.