When called directly or indirectly during a /load, /exit aborts execution of all enclosing macro bodies, and aborts n (default 1) enclosing /load's.
When called outside of a /load, /exit has no effect.
Example: one way to prevent a file from being loaded more than once is to put commands like these at the beginning of the file:
/if (variable) /exit%; /endif /set variable=1...where variable is the name of the file or some other unique name.
See: /load, /return, /break, /loaded