How to check whether a minor mode(.e.g flymake-mode) is on?

Question

I always get error when use flymake-mode. And flymake-mode turn off. So I want to check whether flymake-mode is on. If it is not on, I will turn it on before call flymake-next-error. Thanks.

Accepted Answer

Most minor modes are defined using the `define-minor-mode` macro. For buffer-local modes, that macro creates a buffer-local variable of the same name as the mode itself1. The variable is non-`nil` when the mode is enabled for the current buffer.

Therefore to check whether `flymake-mode` is enabled, you can test the variable `flymake-mode` (noting that this variable might not be defined at all if the mode has not been enabled):

```
(and (boundp 'flymake-mode) flymake-mode)
```

Which, as Thom point out in the comments, can be expressed using the convenient macro:

```
(bound-and-true-p flymake-mode)
```

Which we can use as the condition for an `if` or `when` or `unless` expression:

```
(if (bound-and-true-p flymake-mode)
    (message "flymake-mode is on")
  (message "flymake-mode is off"))
```

1 For global minor modes, the corresponding variable is global; but flymake-mode is buffer-local.

How to check whether a minor mode(.e.g flymake-mode) is on?

Solution

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