emacsflymake

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


I always get error when use flymake-mode. And flymake-mode turn off.

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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.


Solution

  • 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.