Security
The Component Object Model (COM) effectively creates reusable functions that can be linked together quickly to build applications or utilize Windows-family OS services. Unlike source-level reuse (ATL), which relies on language specifics, COM modules are structured purely through binaries generated by compilers; their structure is determined solely by binaries so programs from any language can access and work with them efficiently. GUIDs (Globally Unique Identifiers) are used as GUID identifiers, making working with these modules effortless, as GUIDs are just 128-bit numbers that any programming language can utilize directly.
COM is also used to facilitate interaction between client and server code, for instance, looking up CLSIDs in the registry, getting a pointer to the COM server, and loading that server into memory automatically.
