ServiceTypeConstants

The Win32 service-type values. Read into ServiceManager.Type at configuration time and reported back by the SCM through ServiceState.Type at query time. Determines whether the service runs in its own process, in a shared host process, or is a kernel driver — and, historically, whether it can interact with the desktop.

Constant	Value	Description
tbServiceTypeKernelDriver	1	A kernel-mode driver. Not applicable to twinBASIC services — kernel drivers are written in C and built against the Windows DDK.
tbServiceTypeSystemDriver	2	A file-system kernel driver. Same caveat as above.
tbServiceTypeAdapter	4	Legacy adapter service (network-adapter binding). Not used by modern services.
tbServiceTypeRecognizerDriver	8	A file-system-recognizer driver. Kernel-only.
tbServiceTypeOwnProcess	16	The service runs in its own dedicated EXE process. The typical setting for a one-service EXE.
tbServiceTypeShareProcess	32	The service runs alongside other services in a shared host EXE. Used when one EXE hosts multiple distinct services (ConfigureNew called more than once); the SCM keeps a single process alive that serves all of them.
tbServiceTypeOwnProcessInteractive	272	tbServiceTypeOwnProcess with the interactive bit (SERVICE_INTERACTIVE_PROCESS) set. Not supported on Windows Vista and later — see note below.
tbServiceTypeShareProcessInteractive	288	tbServiceTypeShareProcess with the interactive bit set. Same caveat as above.

Note

Windows Vista and later run services in Session 0, which has no user desktop and no message-loop interaction with logged-in users — the SERVICE_INTERACTIVE_PROCESS flag is silently ignored. The Interactive constants are kept in the enum for compatibility, but services that need user-interface elements should use a separate UI process (launched via the Services package or via inter-process communication) rather than the interactive-service mechanism.

For user-mode twinBASIC services, the only two values that matter in practice are tbServiceTypeOwnProcess and tbServiceTypeShareProcess.