Q:

What are the 0x3F 0xB3 bytes for in /dev/fsevents?

I am experimenting with the filemon source code. I'm debugging why it crashes on iOS 7. I do not have much experience in fsevents but I noticed that in the bytestream it could read off of from /dev/fsevents it follows this pattern:
(fileop info) (args) 0x3F 0xB3 (fileop info) (args)
Where an arg in (args) follow this format:
(arg id) (arg len) (arg value)
What is 0x3F 0xB3 for? I guess it means 0xBEEF? Is it correct to assume it is a sentinel to separate different file operation info in /dev/fsevents?

A:

From this header file:
#define FSE_ARG_DONE     0xb33f   // no more arguments

So, yes, it's used as a sentinel.

