in which keymap to set SIGUSR-handler

[Shynur Xie]

Hi, friends.  I'm reading the elisp manual.  In 22.7.12 Miscellaneous
System Events
(<https://gnu.org/s/emacs/manual/html_node/elisp/Misc-Events.html>),
there's a sample code about SIGUSR:

    (keymap-set special-event-map "<sigusr1>" 'sigusr-handler)

In 22.7.13 Event Examples
(<https://gnu.org/s/emacs/manual/html_node/elisp/Event-Examples.html>)
there's another one:

    (keymap-global-set "<signal> <usr1>" 'usr1-handler)

Which one should I use in my init file?  Thanks in advance.