Published: July 16, 2012
Sets the status associated with a message (for example, whether that message is marked for deletion).
The IMAPIFolder::SetMessageStatus method sets the message status to the value that is stored in its PR_MSG_STATUS (PidTagMessageStatus) property.
How the message status bits are set, cleared, and used depends completely on your implementation, except that bits 0 through 15 are reserved and must be zero.
A remote transport provider's implementation of this method must follow the semantics described here. There are no special considerations. Clients use this method to set the MSGSTATUS_REMOTE_DOWNLOAD and MSGSTATUS_REMOTE_DELETE bits to indicate that a particular message is to be downloaded or deleted from the remote message store. A remote transport provider does not have to implement the related IMAPIFolder::GetMessageStatus method. Clients must look in the folder's contents table to determine the status of a message.
You can use the PR_MSG_STATUS property of a message to negotiate a message lockout operation with other clients. Designate a bit as the lockout bit. To determine whether the lockout bit was set, examine the previous value for message status in the lpulOldStatus parameter. Use the other bits in the ulNewStatus parameter to track message status without interfering with the lockout bit.