Running multiple instances of the same XPC service (NSXPCConnection)

Question

Is it possible to run multiple instances of the same XPC service using the XPC APIs found in Foundation.framework (NSXPCConnection, etc.)? The docs don't provide much insight on this matter.

EDIT: Did a quick test, and it seems like only one instance of the service is running even though I created two XPC connections. Is there any way to have it run another instance?

Answer 1

A bit late, but the definitive answer to this question is provided in the xpcservice.plist manpage:

ServiceType (default: Application)

The type of the XPC Service specifies how the service is instantiated. The values are:

• Application: Each application will have a unique instance of this service.

• User: There is one instance of the service process created for each user.

• System: There is one instance of the service process for the whole system. System XPC Services are restricted to reside in system frameworks and must be owned by root.

Bottom line: In most cases there is a single instance of an XPC Service and only in the case where different applications can connect to the same service (not even possible when the service is bundled with an app), will there be multiple instances (one-instance-per-app).

Answer 2

I believe XPC services designed for one instance per multiple connections. Probably, it is more convenient to manage named pipes with one running executable. So, the most likely it is impossible to create multiple instances simultaneously.