Is the sharp dollar (#$) sign the same as load-file-name in Emacs?

Question

I see Emacs use #$ in autoload files, but I don't known if there are any difference between #$ and load-file-name. When I use them in a file, they looks like the same and when I print them by M-: they are both nil. So I did some test but only get more confused. Does #$ behave more like __FILE__ in Python?

Answer 1

Ask Emacs.

M-x elisp-index-search RET #$ RET

Internally, the dynamic loading of documentation strings is accomplished by writing compiled files with a special Lisp reader construct, ‘#@COUNT’. This construct skips the next COUNT characters. It also uses the ‘#$’ construct, which stands for “the name of this file, as a string”. Do not use these constructs in Lisp source files; they are not designed to be clear to humans reading the file.