Where does a hook go in the list?
For a normal hook, hook functions should be designed so that the order in which they are executed does not matter. Any dependence on the order is asking for trouble. However, the order is predictable: normally, function goes at the front of the hook list, so it is executed first (barring another add-hook call).
What happens if a function is already present in Hook?
If function is already present in hook (comparing using equal ), then add-hook does not add it a second time. If function has a non- nil property permanent-local-hook, then kill-all-local-variables (or changing major modes) won’t delete it from the hook variable’s local value.
When to use a depth of 100 in add-hook?
One should never use a depth of 100 (or -100), because one can never be sure that no other function will ever need to come before (or after) us. add-hook can handle the cases where hook is void or its value is a single function; it sets or changes the value to a list of functions.
When to use a thread specific hook procedure?
A thread-specific hook procedure is called only in the context of the associated thread. If an application installs a hook procedure for one of its own threads, the hook procedure can be in either the same module as the rest of the application’s code or in a DLL.
How to add a hook to a function?
The recommended way to add a hook function to a hook is by calling add-hook (see Setting Hooks ). The hook functions may be any of the valid kinds of functions that funcall accepts (see What Is a Function ). Most normal hook variables are initially void; add-hook knows how to deal with this.
When to run mode hook in Emacs Lisp?
Every major mode command is supposed to run a normal hook called the mode hook as one of the last steps of initialization. This makes it easy for a user to customize the behavior of the mode, by overriding the buffer-local variable assignments already made by the mode. Most minor mode functions also run a mode hook at the end.