By default Emacs uses tab instead of spaces for indentation, so I changed these 2 variables to change this behavior,

  (setq-default indent-tabs-mode nil)        ;; Disable indent with tabs
  (setq default-tab-width 4)                 ;; Set default indent width

It did change the indent mode from tab to space, but if I press RET, when I am in a programming buffer C++ for example, to enter a new line, I get 2 spaces of indentation instead of 4. How do I set this indentation level to 4 be default globally.

Also when when I am editing a line for example, it auto shift the line back to 2 space of indentation, for some reason, and also re-formats how I wrote the code, for example, I usually write like this,

if (true)
    // 4 spaces for indentation.

If I try to edit or add something, it pushes the lines back to 2 spaces of indentation and also sometimes re-formats the brackets position,

if (true) {
  // 2 spaces for indentation.

I am constantly fighting with this thing, and it gets annoying very quickly sometimes. As far as I know, I did not install any formatting package.

  • I'm guessing this question is a duplicate, but I don't have time to look for it now. Hopefully someone will find it, if so, and then close this as a dup.
    – Drew
    Commented Jun 19, 2021 at 13:38
  • The "sometimes re-formats the brackets position" issue is not a thing that Emacs does by default (to my knowledge). Although you say "As far as I know, I did not install any formatting package." I can only presume that you have unknowingly done exactly this. It's pretty easy to confirm -- just run emacs -Q and confirm the standard behaviour. Assuming it's your own config, you can use the recursive bisection technique to quickly narrow down which piece of your config is responsible.
    – phils
    Commented Nov 16, 2021 at 14:14
  • @phils I think the default c-default-style is set to "gnu" which indents the braces, as stated here - EmacsWiki I have now switched to linux style, but I don't see any difference. At this point I am mostly manually editing brace position every time. I like how doom-emacs has the perfect c-style that I prefer, wish they had a package to set it up.
    – apoorv569
    Commented Nov 17, 2021 at 22:53
  • Indentation can certainly happen automatically, but the "move a bracket from the start of the current line to end of the previous line" issue is not something that I've ever experienced with Emacs, so regardless of the chosen style I don't think that particular kind of reformatting is standard behaviour.
    – phils
    Commented Nov 17, 2021 at 23:40
  • If you are still having problems with the indentation levels, though, that's definitely fixable.
    – phils
    Commented Nov 17, 2021 at 23:41

1 Answer 1


There is no global setting for the indentation width. Instead, each mode has it’s own setting. In c-mode it is called c-basic-offset. In js2-mode it is js2-basic-offset. For lisp-mode there are two: lisp-body-indent and lisp-indent-offset.

You’re probably using c-mode for editing your C++ files, so you should customize the c-basic-offset variable. Run M-x customize-variable then enter the variable name that you would like to change.

  • I'm using c++-mode to edit C++ files. And the value for c-basic-offset is set to set-from-style. So I just change this to 2 or 4, whatever level of spaces I need? There is no c++-basic-offset it seems like.
    – apoorv569
    Commented Jun 19, 2021 at 9:59
  • Oh, right. For c-mode (and therefore for a number of modes derived from it, such as java, awk, csharp, and c++ modes) there is also a more complicated style system that lets you pick where your curly braces go, and other things. You can change the current style by customizing c-default-style; it takes values that are defined in c-style-alist. Use C-h v to look at the help for all of these variables to find out more.
    – db48x
    Commented Jun 19, 2021 at 10:14
  • I think the indentation problem is fixed now I add custom-set-variables '(c-basic-offset 4)) to my init.el file, and it seems to have fixed it. But the formatting problem is still there.
    – apoorv569
    Commented Jun 19, 2021 at 16:07

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