point in the chain. Use discard_cleanups to remove cleanups
from the chain back to a given point, not doing them.
- If the argument is pointer to allocated memory, then you need to
+ If the argument is pointer to allocated memory, then you need
to additionally set the 'free_arg' member to a function that will
free that memory. This function will be called both when the cleanup
is executed and when it's discarded. */