CoRegisterPSClsid function (combaseapi.h)

Enables a downloaded DLL to register its custom interfaces within its running process so that the marshaling code will be able to marshal those interfaces.


HRESULT CoRegisterPSClsid(
  [in] REFIID   riid,
  [in] REFCLSID rclsid


[in] riid

A pointer to the IID of the interface to be registered.

[in] rclsid

A pointer to the CLSID of the DLL that contains the proxy/stub code for the custom interface specified by riid.

Return value

This function can return the standard return values E_INVALIDARG, E_OUTOFMEMORY, and S_OK.


Typically, the code responsible for marshaling an interface pointer into the current running process reads the HKEY_CLASSES_ROOT\Interfaces section of the registry to obtain the CLSID of the DLL containing the ProxyStub code to be loaded. To obtain the ProxyStub CLSIDs for an existing interface, the code calls the CoGetPSClsid function.

In some cases, however, it may be desirable or necessary for an in-process handler or in-process server to make its custom interfaces available without writing to the registry. A DLL downloaded across a network may not even have permission to access the local registry, and because the code originated on another computer, the user, for security purposes, may want to run it in a restricted environment. Or a DLL may have custom interfaces that it uses to talk to a remote server and may also include the ProxyStub code for those interfaces. In such cases, a DLL needs an alternative way to register its interfaces. CoRegisterPSClsid, used in conjunction with CoRegisterClassObject, provides that alternative.


A DLL would typically call CoRegisterPSClsid as shown in the following code fragment.

HRESULT RegisterMyCustomInterface(DWORD *pdwRegistrationKey)
    HRESULT hr = CoRegisterClassObject(CLSID_MyProxyStubClsid,
        hr = CoRegisterPSClsid(IID_MyCustomInterface, CLSID_MyProxyStubClsid);
    return hr;


Requirement Value
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header combaseapi.h (include Objbase.h)
Library Ole32.lib
DLL Ole32.dll

See also