Marshals an interface pointer into the specified stream. Marshalling consists
of writing the appropriate data into the stream so the CoUnmarshalInterface
function can use that data to initialize a proxy object in another process. CoMarshalInterface
can marshal only interfaces derived from IUnknown
| IStream *pStm,
||//Stream used for marshalling
| REFIID riid,
||//Identifies interface being marshalled
| IUnknown *pUnk,
||//Interface pointer being marshalled
| DWORD dwDestContext,
||//Specifies destination process
| void *pvDestContext,
||//Reserved for future use
| DWORD mshlflags
||//Specifies reason for marshalling
Points to the stream to be used during marshalling.
Specifies the IID of the interface pointer being marshaled. This interface
must be derived from the IUnknown
Points to the interface pointer to be marshalled.
Specifies the destination context, which is the process in which the
unmarshalling will be done. The legal values for dwDestContext
are taken from the enumeration MSHCTX
Indicates reserved for future use; must be set to zero by the caller.
Specifies why marshalling is taking place. The legal values for mshlflags
are taken from the MSHLFLAGS
Indicates the interface pointer was marshalled successfully.
Indicates the CoInitialize
function was not called on the current thread before this function was called.
Out of memory.
Indicates one or more arguments are invalid.
Indicates an unexpected error occurred.
Indicates an unspecified error.
See the IStream
interface for information on possible stream access errors.
The main steps that CoMarshalInterface
performs are the following:
- The function checks whether custom marshaling is supported by calling the QueryInterface function on pUnk and asking for an IMarshal interface pointer. If the object does not support custom marshalling, the
function gets an IMarshal interface pointer to the system's standard marshalling implementation.
- Using whichever IMarshal interface pointer it has acquired, the function calls IMarshal::GetUnmarshalClass to get the CLSID of the unmarshaller (the proxy to be created). Then it
writes the CLSID to the stream.
- The function calls IMarshal::MarshalInterface to marshal the interface pointer.
You typically do not need to call this function. OLE calls it from within
interface proxies or stubs that marshal an interface pointer.
The only situation in which you might need to call this function is if you are
performing custom marshalling (that is, writing your own implementation of IMarshal
). Your implementation of IMarshal::MarshalInterface
writes to a stream the data needed to initialize a custom proxy in the
destination context. If your custom proxy will need access to a private object, you
can include an interface pointer to that object as part of the data you write to
the stream. In such situations, if you want to use standard marshalling when
passing the interface pointer, you can call CoMarshalInterface
to do so; this is an example of using standard marshaling within your
implementation of custom marshaling.
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Software for Android Developers
- More information resources
Unix Manual Pages