Other Messaging Technologies

MAPI is a powerful and flexible method for gaining access to messaging capability. Unfortunately, MAPI is not directly accessible to Visual Basic applications. Several messaging technologies are accessible to Visual Basic, some of them providing an interface to MAPI and others ignoring MAPI altogether. The following sections briefly describe these technologies and the circumstances under which they should (or shouldn’t) be used.

Common Messaging Calls (CMC)

Common Messaging Calls (CMC) is a platform-independent API for sending and receiving email. CMC was developed by a group that included the X.400 API Association, the organization that sets standards for programming interfaces to X.400. X.400 is a standard for connecting email networks, and for connecting users to email networks. Applications that are written to the CMC standard are easier to port to other platforms that support CMC than are applications that are written to the MAPI specification because CMC is not a Windows-specific API. However, CMC does not provide the rich interfaces that MAPI and CDO do. For example, CMC doesn’t support the concept of folders, so client applications only have access to the user’s Inbox and Outbox. On Windows platforms, CMC is built on top of MAPI, so it benefits from MAPI’s transport and message store transparency. CMC is not discussed further in this book.

Simple MAPI

Like CMC, Simple MAPI is a set of functions for accessing mail system functionality. It predates ...

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