what's the plus and minus key symbol in vim

Question

I known the keypad is KPlus and KMinus.

i'm try to use <C--> and <C-+> to define the key map but it didn't work. can you known the origin answer? help me. thanks.

Answer 1

It would appear that what you're after is impossible because Ctrl-- doesn't map to an ASCII character. Here's why, according to this answer:

I am not sure, but it might be because <C-;> does not map to an ASCII character. Only @, A-Z, [, \, ], ^ and _ map to ASCII characters (0 through 31 respectively) when combined with Ctrl.

Answer 2

here is a long talk about the same issue:

In many cases, Ctrl + minus produces the same code as Ctrl + underscore (. You might try mapping that instead. Works here under rxvt-unicode with a U.S. keyboard:

map {rhs}

It's also triggered for Ctrl + slash. So, you can't map these to different {rhs}'s: <C--> = <C-_> = <C-/>

I have tried and for me it works. So you can make it work, but c-_ and c-/ will also be mapped to that. You can give it a try:

:map <C-_> :echo "hello"<CR>