Searching for space in LaTeX mode

Question

In Emacs 25.3 (but not 22.3, for example), the search string " " (space) in LaTeX mode is matched by the carriage return character as well as the space character. I can understand why Emacs has been programmed this way: a single carriage return in LaTeX will give a space in the compiled document. However, I'd like to turn this behaviour off in the Emacs search, so that a search for " " returns only spaces. How can I do this?

I've tried looking for answers through Google and through a direct search on SE ("emacs latex mode search") but couldn't find an answer. Grateful for any help.

Answer 1

Try hitting M-s SPC while in isearch to toggle whitespace matching before you type in the space character to search. Also, you might want to check the variable 'search-whitespace-regexp' and its documentation. In my case, it was set to the default value and so searching for " " did not find carriage return, but when set to "[ \t\r\n]+", it does – unless toggled off with M-s SPC.

I found this in the documentation of isearch itself, hit C-h m while in isearch to get there.