vim sets the width of a line of code

Question

I don’t want to write too long code in one line. I want to automatically wrap the line after writing a certain width. How should I configure this?

textwidth=90 has been set

But it does not take effect in the editor (vim has been restarted).

Answer 1

It feels bad to have automatic line wrapping. I used a vertical bar to set the line width, which is equivalent to a reminder. https://github.com/ruanyl/bigvim/blob/master/vimrc#L106

Answer 2

set columns=40

Answer 3

:set tw?

What does it show?

Answer 4

:help wrap