Take a pointer to the `struct lock_file` initialized
with an earlier call to `hold_lock_file_for_update()`,
close the file descriptor and rename the lockfile to its
- final destination.
+ final destination. Returns 0 upon success, a negative
+ value on failure to close(2) or rename(2).
rollback_lock_file::
with an earlier call to `hold_lock_file_for_update()`,
close the file descriptor and remove the lockfile.
+close_lock_file::
+ Take a pointer to the `struct lock_file` initialized
+ with an earlier call to `hold_lock_file_for_update()`,
+ and close the file descriptor. Returns 0 upon success,
+ a negative value on failure to close(2).
+
Because the structure is used in an `atexit(3)` handler, its
storage has to stay throughout the life of the program. It
cannot be an auto variable allocated on the stack.
and simply `exit(3)` from the program, an `atexit(3)` handler
will close and remove the lockfile.
-You should not close the file descriptor you obtained from
-`hold_lock_file_for_update` function yourself. The `struct
+If you need to close the file descriptor you obtained from
+`hold_lock_file_for_update` function yourself, do so by calling
+`close_lock_file()`. You should never call `close(2)` yourself!
+Otherwise the `struct
lock_file` structure still remembers that the file descriptor
needs to be closed, and a later call to `commit_lock_file()` or
`rollback_lock_file()` will result in duplicate calls to