CoRegisterMessageFilter

A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

This function registers with OLE the instance of an EXE application's IMessageFilter interface, which is to be used for handling concurrency issues. DLL object applications cannot register a message filter.

Syntax

HRESULT CoRegisterMessageFilter(
  LPMESSAGEFILTER lpMessageFilter,
  LPMESSAGEFILTER* lplpMessageFilter
);

Parameters

• lpMessageFilter
  [in] Pointer to the IMessageFilter interface on the message filter supplied by the application. Can be NULL, indicating that the current IMessageFilter registration should be revoked.

• lplpMessageFilter
  [out] Address of IMessageFilter* pointer variable that receives the interface pointer to the previously registered message filter.

  If there was no previously registered message filter, the value of *lplpMessageFilter is NULL.

  The value contained in the output variable is rarely NULL, however, containing instead a pointer to the default message filter.

Return Value

• S_OK
  The IMessageFilter instance registered or revoked successfully.

• S_FALSE
  Error registering or revoking IMessageFilter instance.

Remarks

To determine whether the platform supports this function, see Determining Supported COM APIs.

Requirements

See Also

Reference

COM Functions